Reviews by Aetherhole

Satin — a type of favorite weave that produces a characteristically glossy, smooth, or lustrous material.

Aptly named, the Quill Acoustics Satin exhibits the same defining characteristics of the fabric. When you dig deeper into the characteristics and define the word “lustrous,” the description of the Quill Satin becomes even more apropos. Lustrous means, “reflecting light evenly and efficiently without glitter or sparkle.” It truly is smooth and lustrous, both in appearance and sonically, but I will dive deeper into that as I break down my thoughts here. First though, I want to mention that this set was bought by me, Quill Acoustics nor Musicteck asked for or are involved in any way with this review. I was first made aware of this set by a friend who had heard it and talked about its musicality and instrument portrayal, which had seemed like it would be right up my alley. Also before I delve into the sound, let me outline the specifications of this and other tangibles about the product.



Packaging & Accessories



Let me get this out of the way, I have mixed feelings with the packaging of this IEM. I will get some complaints and quibbles out of the way first here. When it comes to the overall packaging, I think the design aspect works. Still, I feel at odds with it. The box loosely resembles a book, and while I like a simple package, I feel if the aesthetics of a book was what they were after, this could have been leaned into even a bit more. Maybe that isn’t what they were going after, but with the paper they chose for the insert, as well as the included unique accessory, which I’ll talk about in a second, it seems like a plausible direction they were going. The next complaint I have is with the gloss-paper belt that wraps it, that has the Quill name/logo. It was haphazardly put on mine, so words didn’t sit squarely or flush on the surface/side and partially wrapped around the box (pictured above). Just for fun I rotated it a bit so it works and looks more clean, aside from some obvious light creases from the original way it was put (pictures below).





Then you open the box and are greeted with a nice stock paper that takes on a weathered, aged page, which outlines the specifications of the IEM itself. It’s a great inclusion, but then you start reading it and find there are grammar mistakes aplenty, easily spotted and strewn throughout the page.



Putting the spec paper aside, you get a nicely laid out presentation of the leather case, the IEMs themselves, a plastic case housing the various ear tips, including a S, M, & L set of Eletech Baroque tips (very nice), along with another set of slightly opaque white tips, too. You also get a little black cylinder-looking thing, which houses what looks like a hybrid fountain tip pen and cleaning brush, which makes me think of the slight book theme the packaging was going with. I think the pen portion might actually be usable if you add ink to the inkwell, but I will not be trying this at all. I think the inclusion of this unique piece is nice, but ultimately a little bit gimmicky as it also doesn’t feel super high quality either. Another qualm with the presentation and packaging is also the fabric that they decided to wrap around the foam lining. The pattern itself is pleasing, in fact, I like fancy the design, but a somewhat obvious missed opportunity here is to make it a more simple and decidedly more SATIN fabric. The included fabric is not smooth to the touch as one would expect.



Okay, last gripe on the packaging before I move on — I feel that the overall packaging size could have been reduced. I think it’s a bit bulky and if it were reduced in size by 15-25%, it would have worked a little bit better. Or, even just cutting the thickness down by a third would’ve gone a long way. This is my opinion and others may feel different. Honestly, I’m being more critical of things here on things that ultimately don’t matter too much, but presentation is the precursor to the experience. Why do I mention all this and nitpick this? Because, spoiler alert, I think so, so highly of the IEM that I want a package that matches the IEM.



With that out of the way, I really, really like the feel of the included brown leather case. It’s sturdy and feels really nice to touch. I love the simplicity of the case with stitching around the top and the logo front and center. The case itself exudes the experience of a premium product. I also mentioned the inclusion of the ET Baroque tips, I am really glad those are included because they have fast become my favorite tips for many IEMs. Also, the included cable, a bespoke PW Audio cable, is also a nice touch. Generally, PW Audio is pretty understated in their presentation and the include cable is no different. Fabric weave, metal chin cinch, metal Y-splitter, and metal connectors for all terminations — all in black. Feels very nice and has just the right amount of heft and weight for my tastes.



Tech Specs and the IEM

Now the main focus of this review, the Quill Satin. Here are the specifications, taken from the paper included (with some grammar corrections).

10 Drivers in a Quadbrid Configuration (1x 10mm Custom Titanium-PU Hybrid “QForce” Dynamic Driver, 7x BAs from Sonion and Knowles, 1x 7.2mm House Designed “Silken” Planar Magnetic Driver, and 1 Full Range PZT Bone Conduction Driver)

• 7-way Passive Crossover
• Frequency Response: 20Hz-45kHz
• Sensitivity 102dB @1mW
• Impedance 36ohms@1kHz
• Trio-Pass Multi-layering Phase System for natural timbre and precision phase accuracy
• Micron-grade bass filters (patent technology) for ultra-clean yet impactful bass response
• Hybrid sound tunnel materials (patent pending). Different hybrid materials are used for different frequencies in order to get the optimum timbre.
• Silky texture full-color additive 3D printed shell.
• Top-grade inner wiring and soldering made in Japan.
• Custom-tuned PWAudio InQ OCC cable, 0.78mm 2-pin connector.

Some general thoughts on the IEM aesthetics and feel itself. This IEM is large. I’ve posted pictures of it next to the Hercules Moses, just for reference. There are contours to make it more ergonomic to the human ear, however not everyone’s ear shape are the same. The nozzles are also on the larger size. I don’t have calipers to measure their size, but this is another aspect that maybe of concern to some. The size and shell shape might be a deal-breaker for some, but I’ve found even if it is bigger than some, it doesn’t put pressure on the inside of my ear. Finding the right tip is going to be important. Additionally, the shell all around is very smooth and rounded around every edge so it may still be comfortable. The 2-pin insert is flush with the outer shell. I do prefer recessed 2-pin connectors, but it’s not a deal breaker. Despite its large size, the resin shell weight is quite reasonable. Each shell measures 7 grams on my kitchen scale.



Just for my personal ears, this fits extremely nicely. In fact, it is one of the best matched size and shaped IEMs for my ears from any universal IEM to date. With the included medium Baroque tips, I can wear these in my ears for hours upon hours on end. There are no pressure points on any part of my ear, which is astonishing. Despite my larger ears, I often find issue with the fit of IEMs in my ears. For example, the Canpur CP622B put pressure on several spots in my ear, despite being slightly smaller. Other smaller IEMs, like the Fir or 64Audio iems have issue staying in my ear because they are too small. Then there are other larger IEMs that cause fitment issues for some, like the AK&EE Novus, which I had no problems with. Same goes with the Forté Ears Macbeth and Mefisto (release imminent), both slightly larger shells, but fit very comfortably in my ears. Getting a good fit and seal are monumental for IEMs and Satin aces this for me aplomb. Now onto the sound.

Treble

I don’t usually start with treble when sharing thoughts, but the treble is going to be a divisive topic when it comes to Satin. I am sensitive to treble, but I’m not adverse to it if done well. Satin has extension, but what it doesn’t have is an excess of lower treble energy that we often find around the ear gain region. There’s a bit of a pull back in this area, which makes Satin’s sonic characteristic in the treble pretty unique sounding, to me. I’m including a graph that Leo recently shared in the Satin thread.



As you can see with the graph, areas where you expect to see more energy, the 4k to 8k region is a little bit less energetic than right before and right after those regions. You can also see that it does lift in the lower air frequencies. To me, this solves one of the biggest areas of sensitivities. However, that’s not to say it doesn’t take you a bit by surprise when you first hear it. To me, this actually gives the treble characteristic a sense of note weight. What it doesn’t do is give an overly shiny or shimmery sparkle that we generally come to expect.

I think this day and age we are given sparkle, we are given shimmer, but I think oftentimes we are given it full bore. Instead, Satin does this tastefully. There’s still a good sense of air and space. It also harkens back to what I said at the beginning, the IEM embodies the characteristic of the term “Lustrous” or ”reflecting light evenly and efficiently without glitter or sparkle.” This is where I think the division will come for people. The expectation of overt shimmer and sparkle is going to leave some people disappointed, at least at first. However, giving an opportunity to adjust, all the detail and treble is still there. It’s not veiled; it’s there. To my ears it’s still plentiful, and it takes on more of that body-filled characteristic. It’s more realistic-sounding. Chimes, triangles, crashes, rides, toms, along with the upper harmonics of horns and harps are ever present, but without shrill or piercing nature.

There’s a few tracks/albums I use to test overemphasis of treble, especially in the lower treble area, and Satin nary blinked as it delivered each to my utter satisfaction. Radiohead’s song “Creep” is notoriously sibilant. Metallica’s live album “S&M” also has a lot of treble energy that can be fatiguing after a while on other sets. Both “Creep” and the entire “S&M” album were listenable in their entirety.



Midrange

I was chatting with some friends when I first got the set that the midrange is unlike anything I’ve heard before. I think after some time more time, that statement still holds true. The midrange on the Satin is focused. I would even call this set a midrange forward set, which I typically avoid, mostly because I think it can often sound thin or shouty, or both. The specific area of midrange where I can have sensitivity is handled beautifully, which is the upper midrange. There’s a good amount of energy in the Satin. Typically this part of the frequency range resonates a lot for me. Thankfully, I don’t quite get that from the Satin. This is an especially important area though because I think this is where a lot of the magic can happen, too. The upper regions of drum hits especially come from this energy and I get a good amount of that. In fact, the thing that I keep saying to myself is how lively and real drum kits sound. The initial thwacks and attacks sound and feel tangible.

It doesn’t stop with drum kits either. I’d be remiss if I didn’t mention guitar presentation on this set while in the same breath as drums. Leo of Musicteck fame is a drummer, and the other counterpart in Quill Satin’s company, John, is a musician and a guitarist (among other things). So of course, when tuning these, the two instruments they are going to hear and likely focus on are drums and guitars. I’m sure getting them to sound right to their ears was important. Guitar string plucks, resonate and you can sometimes feel it happen. The vibrations of the strings and the amplification whether from the body of an acoustic guitar or through external amplification are actually noticeable to my ears. Listening to rock and metal music, like Syncatto, Metallica, Gojira, Bernth, Polyphia, Guns N’ Roses, Led Zeppelin, Queen, Muse, Avenged Sevenfold and so many more, I just could not stop from feeling pulled into the music because of how Satin handles the mids.

I’ve mentioned elsewhere, I am a vocalist and a working musician (though I wouldn’t classify myself as a professional). Vocal and instrument timbre can make or break a set for me. Why I gravitate to this set is because of the timbral characteristic of the midrange. Instruments and vocals are almost at the forefront and it’s utterly engaging here. Tangible is a word that I could easily use to describe everything within the midrange. Listening to orchestral music, chamber music, vocal music, there’s a sheer grip and textural feeling I perceive.



Note weight once again plays a large part in the perception of tangibility and texture. Vocals have body, though aren’t overly hefty. There’s not any thinness here either. It’s an appropriate level of maturity in the vocals. Listening to female vocals is marvelous, like from Dominique Fils Aime, Adele, Tracy Chapman, Diana Krall, Billie Eilish with their decidedly rich alto timbre, then to the glorious sopranos, including Cecilia Bartoli, Kate Lott, Wallis Guinta, Maria Callas, Renee Fleming. Male vocals are weighty without being overly husky or bloated either.

Listening to some of my male chamber singers, like Chanticleer, floating counter-tenors to the rich low basses all resonate beautifully. Solo singers like the operatic tenor, Lawrence Brownlee, or Juan Diego Florez, command presence as their vocals ring through in sheer magnificent, so much so, I kept getting lost as I would close my eyes listening to their vocals. A modern pop bass vocalist I reference often is Geoff Castellucci. He sings in a pop acapella group called, VoicePlay, but also has released solo works and one being my favorite covers of the Simon and Garfunkel song, “The Sound of Silence.” With a lower midrange focus, this can tend to be bloated and bled into by the bass region, but his voice is resoundingly rich with lots of presence without feeling overly chesty. However, this particular song does reach depths into the nether depths, too, so it seems appropriate to transition to the bass aspect of the Quill Satin.

Normally, I don’t tend to be drawn to mid-centric IEMs, but this IEM strikes a chord differently. Generally, mid-centric headphones and IEMs are too shouty for my taste, where I don’t find Satin to be at all. Mids are strong and commanding, but without ever becoming so mid-forward that everything else takes a back seat.



Bass

Glorious. Texturally strong, but also lots of bass. Don’t be fooled by the frequency graph. It’s not as bass dominant as one would think. Quill Satin is not an overly bass heavy set, but it is still commanding and palpable. The upper bass is thick, going along with the lower midrange that I mentioned with Geoff Castelluci’s voice, there’s a warmth and richness. It’s appropriately balanced to the rest of the frequency range above it. Midbass is ever present and punches and slams with authority. It’s not a midbass focused set, though, as there’s not a lot of midbass bloom, which is a good thing. Bass guitars sound weighty and aggressive. There’s a couple bass guitar artists that I like, The Omnific and Marcus Miller that sound glorious on Satin. Marcus Miller’s song, “Hylife” is one that has a lot of plucks, articulation, and bass punch throughout that can get lost in the busy passages, especially behind the percussion, pianos, and trumpet, but it is all layered so well. With midbass bloom coherency into the rest of the bass would suffer, especially in that track. I mentioned Satin’s bass is texturally strong. I hear and feel texture as bass notes hit and that’s also partly due to subbass extension.

The subbass though, oh the subbass. If you refer back to the frequency response graph shared above, you see a continuous rise all the way to (and past) 20Hz. There are a few torture test tracks that I use, once is a recent discovery from a head-fi member, which is “Basscomputermix” by Techmaster P.E.B., there are instances where the track goes subsonic and can primiarly be felt in your head, where any bass roll-off would make those frequencies just sound like the bass disappears. The 1:49 minute mark and the 6:52 minute mark are a couple of those instances. It’s not lost on Satin at all and the bass seems to just keep going and going. There’s other songs like Reid Willis’ “Dog Baits Man” or “Limit to your Love” by James Blake that also pressurize your head. Equally impressive is “Fading Sun” by Terje Isungset. What’s interesting is that the bass isn’t overwhelming and maintains balance and constant composure. On some IEMs it can be almost just a one note vacuum in your head. Satin keeps it balanced and keeps it taut. It feels and sounds well balanced and you can still make out the subtleties within this richly layered track.



Detail, Soundstage, & Holography

This set has a lot of detail and comes even moreso in the form of textural detail versus sparkle and shimmer. The set doesn’t exude treble detail, but the detail is still there. It’s not lost, rather it’s just not as prominent as one might be used to from other sets. I’d highly suggest for listeners to allow for mental adjustments when beginning to Satin. Midrange and bass detail and texture is fantastic though. It’s a bit superfluous to say, but I am hearing/noticing details (maybe even feeling) that I’ve not heard in any IEM before and moreso in the midrange and bass.

Soundstage-wise, Satin isn’t the biggest. It’s still relatively large to my ears and can get bigger with different cable or source pairings. With the note-weight characteristic across the frequency response, I think it makes the Satin perceptually a little bit more narrow. However, with the note separation and air extension, I still find there’s a good sense of space and layering. For example some orchestral tracks can sound appropriately large. As I listened to the “Trinity” track off of the Oppenheimer movie soundtrack, I still hear depth with the strings closer than the horn section and it still sounds grandiose. “This is Berk” from the How To Train Your Dragon soundtrack is another good example of expansiveness. Separation and layering between the string section, horns, and the woodwinds is easily discernible. In a different realm of the musical spectrum, “When I’m in the Mood” by Infected Mushroom has track layers upon layers that are both close and extending far out. This is one track that layers can easily get lost with thicker, boomier bass, too.

There’s also a sense of height from the soundstage that I get from the Satin. The track “Digital Ripples” by Ludwig Forsell has instances where sound cues appear above my head. There are other sounds that move through the sound space and you can easily follow each of them. Another good couple of tracks are Yosi Horikawa’s “Bubbles” and “Fluid” track. The bouncing and the zipping of sounds is expansive and weighty, but without the reliance of overemphasized treble and thin mids to portray distant sounds. An additional factor that I think contributes to the intriguing soundstage is something I’ve not even touched on yet, which is the bone conduction driver.



Bone Conduction Driver

Satin uses a full range PZT BCD. As with other aspects of the IEM, the BCD implementation is balanced and very tastefully done. I read that Quill wanted to use the BCD to enhance the cohesion of the different drivers used and I think they managed to do that in spades. It manages the balance of being effective while not being intrusive. There are other sets, like the KB Ears KB02, the ZEmpire ZE51B, or Flipears Aegis and Legion, that are aggressive, aggressive BCDs that it’s plainly obvious the driver is working. That is both a good and bad thing, personally. I think they can be a bit jarring and sometimes a bit gimmicky. Don’t get me wrong, though, I do like and own a couple of those sets, still, as they have their place. To my ears the BCD on Satin works for both enhancing the tactility and enhancing the frequency response. The overall sound just has a tactility that is physical and engaging. The coherency across the frequency range is remarkable. Treble seems to have the same weight as the bass and the bass has the same weight as the midrange. One aspect does not seem to take a backseat to another.

This experience with the BCD, will rely a lot on the fit you are able to get with the Satin. As mentioned, the shells of these fit so well, so much of the IEM surface makes contact with my ears. If these IEMs stick out of your ear or don’t make contact as much with your ears, I’m sure the effects of the bone conduction will be lessened as well.



Scalability & Other Notes

Quill Acoustics Satin scales with more power and with different sources. I tried multiple different sources, including my HiBy x Evangelion R4, Shanling M8T, Mola Mola Tambaqui (4-pin XLR out with adapter), and then on my full desktop rig with the MMT DAC and Riviera AIC-10 amp. Each one sounded unique and different. Even switching between the different modes on the Shanling M8T, from solid state to the two different tube modes, the character of the Satin changes with each. On the full desktop rig, the experience is just awe-inspiring. Satin takes on this full and even meatier presentation that never felt like too much. Dynamics expand and holography improves. The amount of bass authority and punch from the desktop rig was addicting. In comparison, other IEMs, like the Hercules Moses didn’t fare as well off of the Riviera. It was just too much, with too much bloom that bled into the midrange. Again, for my preferences, Riviera never felt like too much with Satin. Satin is not a decidedly sensitive of IEMs, so powering it off of my full desktop rig, there wasn’t a concern with noise or hiss.

I also want to add something that I look for in an IEM that is important for me, though it’s mostly not a concern or consideration for most others. How does it sound when I am walking? Why does this matter and why is this a thing? Every weekday I start my work day by taking a 30-35 minute walk around my neighborhood and I use my IEMs to accompany me during this time. The problem while walking is that the thumps and bumps as you walk, suck up the bass and the overall body of the sound you perceive. So how does the Satin fare on this one-off test of mine? Wonderfully. There’s still enough body and weight to the sound to make it sound balanced. Bass is still felt and heard, and easily so. I figured I’d mention this unique situation because maybe there are others that will be using it on the go, too.

Another bonus for me is that there’s not much sound leakage while I listen. This isn’t a huge concern, but part of the appeal to IEMs is that my family doesn’t have to hear what I am listening to at all. It’s pretty well sealed off. Other sets I’ve had will still leak sound out when listening much more than Satin does.

Cable Pairings

I did have an opportunity to spend time listening to the stock cable quite a bit, but also spent a lot of time trying the Effect Audio Centurion cable that a friend graciously loaned me. I also got to try a whole smattering of different cables with it, too, including the following:

I will say this about cable pairings, this is going to depend significantly on the individual on what they want to enhance on the Satin. Each of the cables I tried were Eletech’s Ode to Laura, The Fifth Ode, Sonnet of Adam, and Ambition cables. I also got to try two cables that are unreleased, which both also had good results, too. Personally, I found the stock PWAudio cable pleasing and generally liked the general characteristics, but also other copper-focused cables to also be favorable to my preference for these. For example the one I spent the most time with, Centurion, leaned out the midbass and midrange a little bit. It provided more dynamic bass impact as well as a sharper focused treble, as well. It wasn’t brighter, though, but it also added some extra air emphasis. Other cables that were not copper focused that I liked were ET Ambition and to a lesser degree Sonnet of Adam.

Again, the stock cable is good sonically, so it’s not exactly something that one should feel compelled to replace. However, one quibble is that the cable is a little bit microphonic, too. When walking with it, I can occasionally hear it. It’s not super prominent, unlike the stock cable from the FF x HBB Deuce that I can hear constantly (I really loathe that cable), but I think the fabric is the primary culprit for the PWAudio InQ cable.



Wrapping Up

Okay, what’s been said that’s not already been said? I’m honestly not sure, since this was a lengthier review. I had a lot to say and if it is already readily apparent, I am enamored by the Quill Satin. I’ve been impressed by other IEMs, but there’s always something, even just one aspect sonically that ends up making it not right for me. With Satin, I am really, really having a hard time finding fault with it. The longer I spent with it, the more incessantly I kept looking, yet not able to find something bothersome to me. It carries a decidedly “W” shaped sound signature that I normally shy away from, mostly due to shoutiness in the midrange. Bass response? Right where I want it. Midrange? It’s a mid-focused set, which I seem to be completely enamored with. Treble? Energetic enough for my taste. Timbral characteristic? Beautiful and engaging. Fit and finish? Like a glove (though, not like OJ Simpson’s glove, for those older folks out there), darn near perfect match for my ears. Aesthetically, it also looks great to my eyes. While it doesn’t make the top of my list for best-looking IEMs, it’s still high up there. Does it pass my morning walk routine? With flying colors. So anything to complain about? Yep.

No set is perfect, but where the imperfections lie are areas that really don’t matter in the grand scheme of things. The included InQ cable is slightly microphonic. The packaging presentation could be better. The included unique accessory, the Pen/cleaning tool is a bit of a wash. Still, as you noticed, I still gave this review a 5.0 Star Review. I don’t think my complaints are enough to ding the IEM because the IEMs themselves are glorious.



All in all, Quill Satin has won me and my heart over. So much so, that I wanted to share my enthusiasm with others, hence the review. I think this set needs to get more visibility. The price is competitive for top of the line sound. Especially in this day and age where top of the line sound comes at a hefty, hefty price, many well over $5,000 USD+. Is it a buy for everyone? It won’t be, I can say that with certainty. Treble heads will want to look elsewhere. Those needing the absolute largest soundstages maybe disappointed. Bass-heads, hmm… this may actually fit the bill, but there are still other sets with more midbass “fun” than Satin. I’m more of a bass-head, but I still want cohesion and detail. Quill Satin provides all of that. However, if you are looking for a rich, yet detailed, and highly musical set, it is an easy recommendation from me; at the very least a recommendation to try when you get a chance. Leo and John Guo, what a marvelous IEM.

KB Ear reached out to me requesting that I check out their product, the KB02. So I willingly accepted, with the caveat that I get to share my honest thoughts, positive and/or negative.

It’s always fascinating when technologies from top of the line products start to trickle down and manifest in more affordable options. I was curious how the KB02 would handle the bone conduction aspect. BCDs seem to be a more recent craze, but I have to admit, I typically like BCD drivers in the IEMs I try. Forté Ears Macbeth, Canpur CP622B, Empire Ears Raven, Astell&Kern x Empire Ears Novus, Unique Melody Multiverse Mentor, Cayin Amber Pearl, each have increase in performance with the usage of the BCDs, at least to my ears. Each of those are multi-kilobuck IEMs, though. Now, when a $39 USD IEM touts having BCD in it, I was both eager and skeptical. I will talk more about its implementation in a little bit.

Let me start by saying, any comparisons that I possibly could compare the KB02 against are not equal or possibly fair comparisons. I may include thoughts and references to some mentioned above because it’s what I have on hand or what I have experience with, but by and large I will avoid doing much comparison and base thoughts and impressions off its own merits.



Build and Aesthetics

Starting with the driver make up, I already talked about the bone conduction driver, which is actually an elastic-type, and a beryllium dynamic driver. This is housed in a lightweight resin shell. The nozzles themselves are metal. The faceplates come in three different options, a blue-style, an orange-style, and a purple-style design faceplate. KB Ears sent me the purple and I quite like the overall look of the faceplate. Simple, yet elegant.

The build of the IEM itself isn’t anything to write home about. When you hold it in your hand or tap it, it feels a bit hollow. That said, it feels sturdy enough to not feel fragile. It is well shaped, too. It’s a medium-sized shell that fits very well in my ear and doesn’t create hotspots or put pressure on my ears at all. It’s also important to note that in order for the bone conduction to work, the more shell to skin/ear contact you get, the better. So wearing these deeper certainly helps maximize the bone conduction.



What’s Included

The cable provided inside the package is a standard affair cable, terminated in 2-pin for the IEMs and 3.5mm to the amp/dac/source. It’s relatively thin and provides relatively minimal microphonics. This is actually important to me because I daily use my IEMs on my morning walks before I start my work. If there are microphonics, or rather excessive microphonics, it is a big mark against the IEM and cable. A recent example of that is the FatFreq x HBB Deuce’s blood cable… horrible microphonics. I can barely use it walking, I can barely use it for my zoom meetings because I can hear the cable rubbing on my shirt, rubbing on my desk, swinging freely… I hear it all.

Additionally in the package, KB Ears provides not one, not two, but THREE sets of different ear tips to use. Really nice. Options are nice, especially at the entry level. I tried a few of them and I think they are fine overall, however for the majority of the review I ended up just using my favorite and go-to eartips, the HifiGo Divinus Velvet eartips. They provide me the best fit and seal.



Also for reference, I listened to the KB02 on a number of different sources just to throughly put it through its paces. Here’s the different configurations:

• iBasso DX340
• HiBy x Evangelion R4
• Questyle M15 tethered to my iPhone
• Macbook Air
• Apple Dongle tethered to iPhone/iPad
• Cayin Soul 170HA with the Mola Mola Tambaqui DAC
• Mola Mola Tambaqui headphone out directly

It’s interesting trying such an affordable IEM off of gear that really doesn’t make sense to pair with, but it was fun to see the maximum capabilities were for the IEM. So, while I tried it on all of those configurations, the obvious question comes to mind, “do the KB02 scale with higher quality sources or chains?” My quick answer… yes, to a degree, though it’s not infinitely scaling. Now onto how these sound.



Sound

I didn’t know what to expect and I also let this set burn-in for a week before I started really evaluating it. I did give it a try a little bit when I first opened it just out of sheer curiosity. I’d say it’s relatively neutrally warm tuned, with a bit of bass lift. It’s touted as a bassy set, but I’ll curb that expectation a bit simply because I’ve listened to some bass-heavy or bass-monster sets and this isn’t quite there. However, neutral with a bass emphasis does better describe it. Timbrally though, I think there’s a bit of metallic sheen to the sound and that’s more noticeable in the treble. I’ll elaborate a bit more on this in the treble section next. It’s not quite natural sounding, unfortunately, which could be partially due to the tuning, but also partially due to the beryllium driver implementation. The bone conduction does also actually factor in the overall timbre, as well, but I’m getting a tiny bit ahead myself.

Treble

Speaking a bit more on the treble, by and large it’s pretty well balanced. It rolls off the higher treble frequencies, so you won’t get a ton of airiness. However, there is a larger peak that presents itself in the treble before the air frequencies. It’s not super spicy, but it sticks out. Where it falls is more noticeable somewhere in the upper frequencies or harmonics of sounds, like cymbal crashes. It’s not overly sharp though, thankfully, it is just more noticeable and does make it sound a little less natural. It does give the treble and overall sound a bit of that sparkle, but I think with the roll off of the air frequencies, it feels just a touch disjointed. I think that this peak/spike does lead to that metallic sheen that I hear from the treble. According to the FR graph that KB Ear shows on their webpage, it occurs around the 11-12kHz region.

Midrange

KB02’s midrange is a bit forward to my ears. It’s overly forward, but there’s a midrange emphasis that does give this set more energy than I’d prefer. The plosive sibilant areas of the vocal region that play between the upper midrange and the lower treble is kept pretty well in check, but the frequencies leading up to the 3K region are pretty emphasized making voices come off a little shouty at times. Tonality in the midrange is pretty good, voices and instruments do not sound thin or overly thick either. Vocals especially feel like they have a nice amount of body, without feeling throaty. There’s a little bit of resonant decay in the lower register of the vocals that I experience and I suspect that is due to the bone conduction. I think overall though, if the midrange was brought down just a little bit, maybe 3dB, it would actually help, one with the touch of shoutiness, but two, with the balance to the bass.



Bass

As mentioned prior, this set is touted to be a bassy set, but I think it’s not quite that. When I think of bassy sets, Nightjar Duality, FatFreq x HBB Deuce, FatFreq Scarlet Mini, FatFreq Grand Maestro all come to mind. This doesn’t compete with those bassy sets, though realistically, it shouldn’t, especially given the price. The bass is not thick and strong, but it’s just slightly more bass-emphasized. Each of those has a distinct emphasis on subbass, which I don’t quite get from this set. It’s just a little bit light on the pressurizing effect you get from the 25Hz-35Hz range that those sets above achieve. However, bass is pretty well defined and not boomy and the bass rise is quite tastefully done, in fact. Mid bass is punchy, but it is just a little bit more pillowy and lacks just a little bit of swiftness. Overall it just lacks a little bit of snap and attack, but the overall tonality of the bass is good. Upper bass is natural sounding. I think the assistance of the bone conduction helps in the bass department, though.

Bone Conduction

So, here’s where I’d like to spend a little bit more time because I think the implementation is multifaceted. The elastic bone conduction implementation is fascinating, cool, effective, if not a bit gimmicky at times. Let me elaborate a little bit on this though.

As I mentioned in the bass section, the BC assists the bass get more tactility, however, the bone conduction doesn’t seem to be isolated to the bass region as I do feel resonating effects from the BC in the midrange, especially in the lower midrange. I had said that there was a bit of resonance decay that I experienced in the lower midrange. What I hear and feel is the elastic BC still vibrating. This is easily noticeable if you pause a song, you’ll hear a very brief sound that sounds like a rubber band instantly being made taut. Kind of sounds like, “thook.” You can also feel the vibrations of the midrange sometimes in the shells themselves, too.

When I spoke about the shell feeling a bit hollow if you tap on it, you can also feel the elasticity of the BC when you do that, too. It makes sense, but you certainly can feel the shells vibrate when you have music going. This is where I think it feels a little bit gimmicky. Yes, it’s effective in the sense that the BC is supposed to vibrate your cartilage, but the amount of vibration is not subtle. If you’ve ever dealt with tactile transducers in theaters or home theaters, the same concept applies. There are implementations that are done tastefully that truly heighten the experience, effectively disappear, and there are transducers that are novel, but ultimately gimmicky and ever-present. Some seemingly just shake and one intensity. The BC in relation to that, isn’t the latter example, thankfully. The elastic BC teeters somewhere in the middle of the transducer range, though. It’s cool and a cost effective way to experience BC to a large degree, but it’s pretty noticeable it’s there and working.

So, is it ultimately a bad thing? No. After spending a few weeks going back and forth between this and other sets, I will say that it’s BC, while noticeably there pretty often, didn’t detract from my listening experience. Your mileage may vary on that, but the elastic bone conduction does its job.



Soundstage

The KB02 soundstage has got more lateral width than forward depth. Bone conduction can also heighten the experience of soundstage and here’s where I find it a bit of a double edged sword. Yes, it does actually help the expansiveness of the soundstage sometimes, but then other times it doesn’t and the overall sound is a bit closed in. That’s probably partially due to the tuning, more specifically in the midrange. However, there isn’t a large amount of depth and holography, though it’s sufficient and likely better than you might expect.

Detail and Resolution

This set is not going to wow anyone with its ability to resolve. The usage of beryllium for the driver I think helps take it a long way, but it’s still a bit smoothed over, partially due to the single dynamic driver and possibly additionally by the elastic bone conductor. There are times you can almost feel/hear the BC after the articulated notes should have dissipated.



Conclusion

I refrained making a whole lot of comparisons to other IEMs, but as I conclude my review I want to make this direct comparative statement — tonally/timbrally, I prefer the KB02 to the FFxHBB Deuce. Subbass and bass overall is still done better qualitatively and quantitatively by the Deuce, but midrange and treble, I feel the KB02 better suits my taste. Now, it’s not perfect as I’ve outlined above with the treble and the midrange, but by and large, it is pretty easy to listen to this IEM.

What does it do right? Makes bone conduction accessible and in a very affordable package. Vocals for the most part sound good. The amount of tips included is quite impressive. The price itself is highly appealing. Now, at the time of writing this review, you can even find these on Amazon for $35 with an $8 coupon. That makes these IEMs $27 dollars! Is it worth it? YES. That’s just silly.

What can be improved? Timbre could be better. Honestly, one might say, what more can you ask for in a $40 (or presently $27) IEM? I find myself thinking that, but then I also look at the landscape of IEMs. Competition is overwhelming, even in this price bracket. So maybe it’s not too much to ask for a little less metallic timbre. It’s an area of improvement, though It’s not a make or break situation here because it’s an affordable option. A slight complaint, though understandable sacrifice, is the lack of 4.4mm terminated cable. The only one is a 3.5mm single-ended cable, which is fine, but something worth noting.

So why did I give it 3.5 stars. All in all, though, I think this is a praiseworthy set. It’s fascinating and despite some of the things I pointed out, doesn’t do anything egregiously wrong, rather I think it does a lot of things right, including the price. What sets the set apart is the ability to experience bone conduction in a different way. Truth be told, I’ve already encouraged a few of my friends to give this set a try.

Immanis – The Journey

Imagine having a headphone that has electrostatic speed and articulation, macro dynamics of dynamic drivers, and bass extension of planar magnetics. That is how I’ve described RAAL 1995’s Immanis many times before. It’s accurate and, it not only exhibits those characteristics, the Immanis rivals the best each of those driver types have to offer. So, what’s the catch? There must be trade-offs, because there always are. There are, but that statement comes with an asterisk… price, no doubt is one. It’s tuning, is going to be the aspect of this headphone is the most off-putting. I will detail that more later in this review. However, for those who don’t have problems with its tuning, Immanis is going to likely be one of the very best offerings you’re likely to come across. I clearly fall in the latter category. Preemptively speaking, you will have to forgive the overall enthusiasm, excitement, and positivity; it’s not often a headphone comes along that revolutionizes the already saturated market. There’s a lot more to say about the Immanis that cannot be summed up into one sentence, though.



My introduction to the Immanis began in June 2024. Danny McKinney of RAAL/Requisite one of the many attendees to a local head-fi gathering. Danny brought the Immanis, Magna, and Feliks Envy, and SAEQ Armageddon for people to demo. I had heard some about the new offerings from RAAL, but my previous experience with the ribbons such as the SR-1a/b or CA-1a/b didn’t leave me overwhelmingly enthusiastic. Don’t get me wrong, they were great, and I valued them for what they were, but were sonically just not my cup of tea. So, when we were at the meetup, I didn’t get around to listening to the Magna and Immanis until much later in the meet. It wasn’t until nearly an hour before the meet was supposed to end that I did, partially because I was expecting to not like it. In fact, I was bracing and hoping NOT to like it. Boy was I wrong. I first listened on Danny’s Envy with both Sophia Electric and WE tubes. A couple brief moments later, I blurted out, “holy hell…” thinking where’d that bass come from? After listening a little bit, I asked Danny if I could try it on my system that I brought. I brought the Holo May, Woo WA23 Luna. I listened to a couple tracks and then pulled a friend over and had him listen. We were enamored. What a great pairing that was. I took the Immanis around to a couple of other systems to get brief impressions, including Cavalli Liquid Glass and Zahl HM-1. I didn’t want to monopolize the Immanis much more, so I returned it to Danny and his listening station. I was more than impressed, but I wanted to spend more time with it.



A friend who already had his on order prior to the meet up said he was going to be getting his in a week or so and he would bring it over to try more on my system at home (same system I brought to the meetup). I gladly jumped on that offer. We were able to listen a bit on my system, but he also borrowed a DNA Stellaris, so we listened on that, paired with his Chord Dave/MScaler. I was again impressed, so much so, the very next day, I reached out to Danny to put my name down to get one here. For the sake of saving the readers from too much exposition, I will just mention that I was able to listen to the Immanis on several additional occasions after first outreach to Danny, including extensively listening to it on numerous systems at CanJam SoCal 2024. So, fast forwarding to nearly four months later, which included an unforeseen delay that pushed it back nearly a whole month, it arrived safe and sound.



Leading up to the arrival, I was a bit worried when I pulled it out of the case, it would be underwhelming. Danny had explained that the ribbons were tuned/tightened so that they would settle/break-in to the full frequency response after about 100 hours. My worry was unfounded, it sounded full and weighty and had powerful bass from the get-go. It made me eager knowing that it would only get deeper. So, I let it break-in continue, but I did listen consistently while it was burning-in.



Aesthetics, Build, & Comfort

I really liked the looks of the headphone the first time I’d seen pictures of them. Admittedly, I am not a huge fan of gold color ways in general, I did concede that it really looked striking and it’s even more striking in person. I was quickly told by my friend that you can get it in silver instead of gold, which immediately piqued my interest. When he came over with his silver Immanis and I got to see it in person, I was sold. I really dug the silver grill and the silver headband. Well wait, but most of the pictures are all the gold Immanis. What happened? Long story short, because of the unforeseen delay and the acquisition of the Cayin Soul 170HA amplifier, I decided I wanted to match the gold of the Cayin with the Immanis. Alex was extremely courteous and obliged my request to switch, so now I have the gold color way. Realistically, the gold is understated, not gaudy, and exudes classiness.



The cups of the Immanis feature a wooden finish, assuming it’s a faux wood of sorts, but it does not look or feel cheap like the Hifiman faux-wood cup offerings. While it’s not a direct color match to the side panel of the Cayin Soul, which is more of a reddish hue, they still look nice together. The pads are hybrid suede, perforated leather with a pronounced angle. They are stiff, but comfortably sit on the sides your head. The inner cup size is massive, cavernous even. I have tall ears which often end up touching either the top or bottom (or both) of the cups of most headphones. My ears don’t touch the inside of the pads at all.



The headphones themselves are quite heavy, too, at 610 grams, but weight distribution really doesn’t make these uncomfortable to wear. Adjusting accordingly to fit your own head, it becomes even more comfortable. Right out of the case, the clamp of the headphone was tighter than I remember. It put a little pressure on the sides of my cheek and temple area, but after a day, I adjusted the metal tension band to lessen the clamp. I also really love the way the metal tension band flairs out and bends from flat to perpendicular to frame the cups. The leather padded headband looks fantastic with the name “RAAL 1995” embossed on top. The gold-colored stitching on the underside is an extremely nice touch and the texture and feel of the padding and suede are wonderful.



The Star-8 silver cable feels sturdy, yet malleable enough to coil and uncoil. The cable between the headphones and the Y-splitter is a little bit more rigid, but I really like that it is. I never feel the cable on my neck, which is not something you think about until it doesn’t. The actual connectors on the cups themselves are quite solid and snug, so inserting and pulling the 3.5mm plugs out requires intent. This is a welcome change to the 3.5mm connectors that are on the Hifiman Susvara, which pull out a little too easy, but additionally wiggling them could even make audio very briefly cut out.

Also included is a cloth stamped with the RAAL 1995 logo in the corner, metallic screw-type stopper for the RCD interface should you opt not to use it as a headphone stand as I am, and a hex wrench to tighten/loosen the earcup adjustment mechanism.

RCD Interface

To drive ribbons properly from regular amplifiers, the RCD Interface is required. RCD stands for Ribbon Current Drive. It houses a toroidal transformer designed to convert the voltage from the amplifier to the current signal necessary to drive the ribbons. This is effectively the same as the RAAL|Requisite TI-1b brick. The new RCD interface, however, does not have the 16 Ohm and 32 Ohm options readily available and you must choose between them (or an 8 Ohm option) upon ordering. The other difference is the RCD interface is now cylindrical, and it has the option to also work as a headphone stand. Clever and, honestly, convenient! That said, I ended up swapping out the headphone stand extension for the included screw cap for the interface so I could tuck it away.



It is very well built and solid feeling all around. The cylinder is anodized on the outside. On the top is a matching wood finish. On the bottom of the unit it is a cork material, which adds padding and protects surfaces it is placed on. The headphone stand portion is made of metal and finished in the same leather on top as the headband of the headphone with the same wood finish on the underside.



RAAL 1995 Suitcase

Most cases that headphones come in are functional and maybe have a flair of style. Some are just industrial looking going more functionality, like pelican or pelican-style cases. Some are more display pieces and not transportable, like a wooden box like some of the ZMF cases. Some are questionably supposed to be display pieces, Hifiman’s Susvara or Susvara Unveiled boxes immediately come to mind. Slightly underwhelming as such, though. Then there are some cases that are functional, transportable, and have flair and a more premium quality to them. Meze Empyrean I, II, and Elite come to mind for those. The Immanis comes in such a case but takes it to the next level. Internals of the case are well cutout and house the headphone and the RCD Interface and lined with a satin material, not uncommon or unlike what Hifiman does with the Susvara, but it feels less haphazardly done here. There’s also space for the two cables (amp to RCD cable and then the RCD to headphone cable).



The outside, however, extremely premium looking and feeling. It’s finish in a silver metallic finish that, if you catch the light right is subtly rainbowy. The hinges and closing snaps each are high quality. Embossed on the outside of the case is the RAAL 1995 logo. The carrying handle, even, is not just one that simply flops over. No, handle design has tension springs that when you let go, it slowly falls back into place. Quite classy overall and something that I only see on premium luggage and suitcases. RAAL could have easily opted for lesser quality components here, but I am sure glad they didn’t. It just additionally shows the attention and care that went into making the entire experience feel substantial.

Enough With Aesthetics. How Does It Sound?

How does it sound? Unlike any headphone I’ve heard. Tonality is unlike other headphones, for better or for worse. Immanis is a divisive headphone because of its tuning. There are other headphones that are tuned untraditionally that have the same split in opinions, like the Abyss 1266TC or the Heddphone 1 and 2. I admire headphones that deviate from traditional tunings, but in most those cases, I don’t find the tuning at all to my preference. Immanis tuning works extremely well for my personal preferences, my ears, and my HRTF. Areas where I am sensitive to peaks, both in the treble and the midrange are absent of issues. However, I know that there are some peaks in the midrange and treble that may bother others. To my ears, it is just supremely smooth sounding and not all fatiguing. Let me get a little granular in the various aspects, though.

*Note for reference, my extensive evaluation was done on my desktop system: DMP-A6 Streamer -> Holo Audio May KTE -> Cayin Soul 170HA -> RAAL 1995 Immanis.

Soundstage & Holography

I’m starting with soundstage and holography because Immanis is huge sounding. Live recordings like orchestras or concerts sound appropriately big. Recordings in churches or very live-sounding venues also give appropriate spacing and reverberation and feel like you are in the middle of that hall. Stepping into studio recordings, I do feel like the space does get a little smaller still. Vocals and instruments closely mic’ed feel closer and even to the point of feeling intimate. The unique thing about Immanis’ presentation though, is it doesn’t ever feel so intimate that vocals or instruments feel so much in your head, like traditional headphones do. Intimate vocals feel appropriately close, as if they were within inches or feet of you. Additionally, having both aspects all at once is really cool. An album that showcases this duality is “Sessions from the 17th Ward” by Amber Rubarth. Amber’s vocals are center stage and close, while the guitar, fiddle, percussions, and cello have very distinct positions in the soundstage, with each feeling slightly different in distance from the listener.

I feel part of how large it sounds is just how open it feels while on your head. Yes, you physically feel the earcups and the weight of the headphone on your head, but your ears really don’t “feel enclosed.” I think that’s partly because there is a portion within the earcups, in front of the ribbons that is completely open, which you can see straight through. This allows ventilation primarily for the ribbon’s sake, so you’re not creating pressure when putting on or taking off the headphones, which could over-exert the ribbons. Because of that space, you can hear your surroundings as if headphones weren’t on your head, even more than any other traditional headphone.



Instrument separation and layering is extremely convincing, too, especially with the right gear. Positioning sound cues and instruments around the sound stage is easy to do and getting a sense of three-dimensional depth is equally easy. Immanis also stages vertically, too. An example is the song, “Digital Ripples” by Ludvig Forssell that give you that height immersion. Of the headphones and systems I’ve heard so far, Immanis does size, depth, and positioning best. I’m told the Shangri-La Sr. is even better, but the very brief experience I had with it, I really couldn’t get a gauge that.

I will also say that the Immanis can sound/feel flatter, depending on the source chain. For example, for kicks and giggles I tried it off the iBasso DX320MAX Ti using a 4-pin XLR to 4.4mm adapter. While the iBasso DAP can run the headphone to decent volumes, soundstage was pulled in. Honestly, it was just more surprising that the iBasso does as good job at running the Immanis that I think it fills a gap allowing me to enjoy it in transportable fashion! Bass was slightly lighter, compared to the Cayin Soul, though surprisingly not devoid. Speaking of bass…

It's All About the Bass

As I mentioned in my first impressions paragraph, bass was one of the first things that I noticed with Immanis. I wasn’t exactly sure what to expect, given previous experience with the SR-1a/b and CA-1a. Additionally, people also have raved about other headphones having great bass, e.g. Stax SR-X9000. I eagerly listened to the X9000 for the first time in CanJam So Cal 2023, but when I listened for bass, my first thought was, “where is it?!” So, color me thoroughly impressed when I heard the bass on Immanis. Upon first listen, I owned the Susvara OG and the Atrium Open, both of which are known for their bass characteristics. I wasn’t expecting the overall experience to exceed my experience with those, but it certainly did.

As I’ve now gotten a lot more time with the Immanis in my home, I can say without a doubt that this is some of the bass reproduction I’ve heard to date from a headphone. Sure, a couple headphones slam harder, like the Abyss 1266TC or even a very well driven Atrium Open or Closed, but I think that the bass on the Immanis strikes a balance of everything. Its bass can be classified as a “Jack-of-all-trades” and a master in most (areas).

I’ve not heard bass be as authoritative and well-controlled as I have on this headphone. Again, my previous reference headphone, Susvara, is extremely good in bass speed. However, the lift in amount of articulation and kick, even in the busiest passages, is astounding. The recovery and attack of double kick drums had me repeating sequences in songs numerous times just to hear it again and again. Being able to even delineate bass instruments and drums during some of these passages so many other instruments and vocals going on is remarkable. For example, I listened to the entirety of Michael Giacchino’s “Incredibles 2” OST, just because each track had something new to listen for. So many great tracks on that album where you get bass articulation, along with so much more, but everything sounds impeccably balanced. Punch, weight, speed, depth, it has it all. The track, “Devtechno!” has some fun weighty bass that showcases just the balance of all the aspects of the bass. Even the acapella songs at the end of the album are engaging to pay attention to, for bass reproduction.



I’d be remiss to not articulate just how deep the Immanis can play. Nowadays I find myself listening to a lot more music that requires the ability to play deep, deep sub-bass. Hans Zimmer’s soundtracks often have a good mixture of sub bass, but hip-hop, rap, EDM, electronic, all have made more of a presence in my regular rotation. Tracks like, “Limit to Your Love” by James Blake, “Me and Your Mama” by Childish Gambino, “Redrum” by 21 Savage, “Kill Jill” by Big Boy, “It Goes in Waves” by Inzo are great examples of heavy, deep bass. Immanis isn’t the last authority when it comes to the ability to pressurize your noggin, but it truly doesn’t leave me wanting much more from a headphone.

Another benefit to the driver technology is that it does not rely on the seal to maintain bass depth and integrity. The icing on the proverbial cake here is the bass texture. It seems no matter the frequency in the bass, you still get texture and clarity. A great track that features rich, rich bass-guitar texture and prominence is “Half-Life” by Peter Weniger. It seems to always retain its bass composure. The summation of all of this is remarkable, really.

Treble

I don’t end up talking about treble as much as other aspects of a headphone, but its importance is as equally weighted as all other sonic aspects, especially with consideration to the bass. They often are the bookends to my sonic experience and the truth of it is, treble can make or break that overall experience. If treble is too sparkly, it can feel like the energy is just lobotomizing my skull. If a headphone is rolled off in the treble, the sound often feels muffled and claustrophobic. The Sennheiser HD600 series exhibits this trait to my ears. With Immanis, I find the treble to be quite smooth and natural. It does sound quite neutral to my ears. To my ears, I find it similar in energy to the Susvara OG. I know others will hear it differently, though.

When I first heard it along with the Magna, I found neither to be piercing, but Magna to my ears was a little bit peakier and uneven. Not largely so, but Immanis just sounded more consistent throughout the treble frequencies. Tracks that have a lot of treble energy, like “Hit the Lights” by Bensley, retain its clarity without getting excessively edgy. It always stays on the correct side of sharp here.

One thing I often am listening for is tonality and timbre of the upper registers of drum kits. One of the quickest ways to turn me off from a headphone is weird drums reproduction. Hi-hats, crash, and cymbals need to have the right energy to not come off too forward or too recessed. A track that I often use to test this is “Chocolate Chip Trip” by Tool, where Danny Carey’s skills are the focal point. I also really like using songs from the band 311. The tone of the drums is quite unique and can equally show irregularities in the treble energy. The cymbal energy can either retain excess splash on brighter headphones or feel devoid, but the balance on the Immanis is squarely in between and sounds quite right to my ears.

I’ve mentioned texture already, but the application of texture in the treble region is yet another a standout feature to this headphone. Despite having treble detail and articulation of an electrostatic headphone, it doesn’t exhibit the weightlessness and wispy nature those headphones typically do. Even the treble frequencies have a tangible characteristic. There’s also plenty of air frequencies that add to the spatial presentation. A track that I listened to that took me by surprise was “Together Again” by Janet Jackson. At the beginning of the track there’s a couple of harp glissandos along with some sparkly textures layered on top. The first time I heard this, I could practically feel the strings of the harp as they were plucked. The harp notes themselves traveled back and forth from ear to ear with the shimmer of the sparkle just chimed and floated out of nowhere.



Midrange

This is where the headphone becomes the most divisive, its midrange. It’s a bit recessed and it does affect how the sound presents itself. Some are going to find it quite distant sounding, which I understand the criticism. While it can feel/sound recessed comparatively to other headphones, Immanis is leaning heavily into that difference. Despite the recession, I find the overall tonality of the midrange still quite pleasing. Vocals and instruments still sound and feel correct to my ears. I also don’t entirely subscribe to the notion that its midrange presentation makes everything sound far away. That is one of my biggest complaints about the Sennheiser HD800, Immanis doesn’t do that. I think a bit of adjustment, or even brain burn-in, might be necessary to fully appreciate the difference.

There’s more nuance to the midrange and its presentation. It can sound large, it can sound far away, however, it can sound quite intimate… appropriately so. For example, Sarah McLachlan’s “Angel” and “Adia” can sound like she is right in front of you. Other instances where vocals can sound a bit further away, “High and Dry” by Radiohead. Chamber groups can sound further still, positioned equidistant around the listener, like many tracks by the vocal chamber group Voces8. Pushing things further back, larger choral works and orchestras can sound expansive and like they’re on the other side of the theater. Again, I think this is different than we are accustomed to experiencing, especially on headphones and it’ll be up to the user to determine whether it’s something they can grow accustomed to or not.

Even with the tuning and distance perception differences, I did make mention that I do think vocals and instruments sound correct to my ears. This is extremely important to me. Tonality and weight to voices sound balanced to my ears. Male vocals feel naturally weighted, not overly hefty nor thin. A modern male acapella group, Home Free, has a rich bassist and a light agile tenor that I’ve used to test vocal weight. Home Free’s covers of “Man of Constant Sorrow” and “Ring of Fire (feat. Avi Kaplan)” are great examples that showcase the different vocal timbres, deep, rich vocal bass and lighter tenors adding top end harmony. Home Free is more studio recorded, so for more live-recorded male vocals, I turn to Chanticleer. Many wonderful examples from that group for extensive male vocal ranges often recorded in livelier, more natural acoustics. I also really liking using tracks and albums from the vocal group Voces8 and Voctave, covering both extreme vocal ranges for both males and females.

Guitars and string instruments are engaging on Immanis. A friend introduced me to some fantastic guitar-focused rock groups, like Night Verses or Syncatto that have been on regular rotation during my listening sessions. A couple tracks are “8 Gates of Pleasure” and “No Moon” by Night Verses. The electric guitar and its unique character and distortion is tangible even with heavy drums being played. On the more classical string instruments side, there was a track that was featured in the movie “Arrival” with Amy Adams that I enjoy listening to. The track is called “Richter: On the Nature of Daylight” that struck an emotional connection I’ve only previously experienced while watching that movie. Part of that emotional engagement is the connection to the movie, sure, but part of it certainly came from the texture of the bow strings moving across the strings that I could feel as I closed my eyes. The entire “Oppenheimer” soundtrack by Hans Zimmer is also a great showcase for string-focused listening.

Other instruments, including pianos have just the right amount of presence and correct timbre. Horns, such as when trumpets blare have just the right amount of forwardness. Using the track, “Copland: Fanfare for the Common Man” off the Classic at the Pops album by Erich Kunzel & Cincinnati Pops Orchestra showcases this beautifully. Other mid-forward transducers tend to have a bit too much shout and forwardness for my taste. For a piano track that I like listening using, “Piano Concerto No. 2, Allegro, Opus 102” off the Fantasia 2000 film soundtrack showcase Immanis’ ability to articulate the frantic piano soloist and its timbre, while being backed by the Chicago Symphony Orchestra. At moment you can focus on the piano and swap focus to individual instruments in the orchestra and back with no problems. There’s just no smear or muddiness.

The midrange is fascinating to me, partly because I can get that emotional engagement, but also get the wide range of intimate to large presentation. The bonus to me with Immanis’ midrange characteristic is just how long I can listen to it at a time. Because of the recession I don’t get shout, and I don’t get thin vocals or instruments, yet retain tonally correct mids.



Detail & Articulation & Timbre

Another big draw for me to this headphone is its resolving capabilities. Even in the busiest passages detail separation and layering sound effortless by Immanis. Its ability to exude near-instantaneous onsets and decays allow more detail and texture to come through. One of my favorite tracks to test articulation is Daft Punk’s “Giorgio by Moroder.” The natural progression of the song escalates with more and more sample layers that it can become a muddy mess. The numerous times I’ve heard this track on Immanis, I catch myself paying close attention to all the intricacies of the track. It’s not just that it sounds effortless because it certainly does, it’s also that I can hear these intricacies in different layers, near and far away.

Busy passages also don’t hinder instrument timbre either. There are several tracks that I’ve been introduced to that showcase this fantastically. I’ll start by mentioning “Adam & Eve” by Cameron Graves. Jazz at it’s most aggressive. Hearing the various instruments in this track has never been easier. “Aurora” by Syncatto & Bernth, “Playing God” by Polyphia, & “Mediterranean Sundance / Rio Ancho (Live at Warfield Theater, San Francisco, CA – December 5, 1980)” by Al Di Meola, John McLaughlin, Paco de Lucia are some amazing tracks for detail, speed, and articulation, without supplanting the timbral integrity of the various instruments (Thanks to those of you who introduced me to those tracks, you know who you are!). The technicalities of this headphone are quite engaging really, and I really have enjoyed experiencing the timbre differences of every instruments. Subtleties and nuances are ever present. There have been many times I’ve found myself playing back a passage just making sure I heard an audial cue in the music that I’d never heard before. It is just so detailed through the entire frequency range.



Supplemental Thoughts

The areas I’ve clearly gushed about are not going to be for everyone. The technical prowess is going to be a bit distracting to some. The tuning, especially in the midrange, will be off-putting to some. Same goes for its bass and treble reproduction. Its soundstage presentation will also not be everyone’s cup of tea. Sound leakage is among the most from a headphone I’ve encountered, both inwards and outwards, which is another thing to consider. The drawback though is this can add to the sense that the presentation is too spacious to some.

One of the biggest benefits of this is ventilation and airflow. Not requiring a seal for bass extension allows this free airflow. I’ve had a handful of 8+ hour listening sessions, nearly nonstop, with the Immanis and my ears barely got warm. This was even during some of the hotter-than-usual Southern California Fall days running my tube amp, effectively turning my office into a relative oven.

Prior to Immanis, my reference headphone was the Hifiman Susvara. Its technical capabilities found of a happy balance that was everything I wanted— articulate, deep rich bass, neutrally tuned with no excessive peaks in the upper range. It also seemingly scaled infinitely. All the appealing aspects of the Susvara that made that headphone my daily driver Immanis takes even further. Drivability-wise, I’m told that it only needs about 1.5W of power, but I’d say that they are not the easiest headphones to drive. From my experience, I had to turn my volume pots to about the same position as I would with the Susvara OG. That said, Immanis is a different beast in drivability. In some ways it’s easier to get to sound good, but it scales infinitely just like the Susvara does. Where I think it differs even more than Susvara, is it is even more source chain revealing and changes even more with different sources.

If you are additionally looking for a more intimate headphone experience, Susvara OG is still a fantastic choice. I think Susvara OG is also a great complimentary headphone to the Immanis. The Susvara Unveiled is also a great alternative, if you are looking for an alternative or complimentary headphone.



Wrapping Up

Immanis in Latin means immense, enormous, huge, vast, monstrous. I could not think of a more aptly named product, because it truly embodies its name. Immanis’ release earlier this year has made enormous waves. It’s not too often I get as excited about a product as I have with the Immanis. And I do still. It’s now been two months since Immanis has arrived here and I am just as eager to put it on and begin listening as I was the first day it arrived.

Immanis’ technical capabilities are among the best on the market. It just about out-resolves everything I’ve heard but does so without sounding thin or losing out bass performance. It’s not a perfect headphone, as I detailed earlier, the midrange is going to be divisive and spatial presentation, too. Though, for me it hits all the right notes. Especially in this hobby, you’ll be hard-pressed to find something that sounds and feels as complete, but Immanis certainly is that product for me.

It has become my daily driver headphone because I’ve not found a genre that this doesn’t do well. I truly have a hard time taking these headphones off my head once they are on. Hours go by while I am listening. Individual headphones might outclass it in specific genres, but as an amalgamation, I don’t find myself wanting anything else. For me and my ears, I don’t feel like I am giving anything up. This headphone has character, top to bottom. So much so, this has become my only headphone, having parted ways with my other headphones. I am just that enamored by them. At this point, I’ve decided that I am no longer looking for a complimentary/supplemental open back headphone. Granted, I’m not one to rotate through headphones much and a bit of a minimalist when it comes to gear, so take that for what you will. I may add a closed-back to the mix just to change things up, but I am in no hurry, and it has to be the right one (Alex, I’m looking at you to make a closed-back version happen!).

There are still going to be plenty that this doesn’t quite fit the same large space it does for me. There are also plenty of people who won’t be as enamored by its tuning. Absolutely valid positions and opinions because we all hear things differently and need different things. However, those who know me here know that I’ve said this since I first experienced this headphone, everyone interested in it, should hear Immanis to determine whether its sonic signature is their cup of tea or not. As I close this review, I’m sure there’s no doubt how much I like this headphone, but my hope from this rather lengthy review, it articulates just what about it that I am hearing and why I enjoy it as much as I do.


(reusing this picture when I first listened to the Immanis on the Cayin Soul at CanJam So Cal)

Flagship headphone gear has really been taken up a notch or two in the last couple of years. The concept of continuous escalation certainly applies. I’d argue that it’s not enough, nor is it just about making functional and good sounding gear, it’s now become about making them more and more beautiful, maybe even required even. They almost have to because the market keeps getting more and more saturated. Lately, it seems like companies are positioning themselves to create flagships that are bold and create a statement. Cayin’s release of the Soul 170HA is aiming to do just that and I adamantly believe they succeeded.

If you’ve ever spent much time in the Cayin Soul 170HA forum thread, it will not come as a surprise that I love this flagship amplifier. When I first heard it at CanJam So Cal 2024, I instantly was enamored and knew I had to listen to it numerous times within those two days just to confirm what I was hearing. Level-setting a little bit— I did not go to CanJam So Cal looking for a new tube amp, in fact, I was more specifically looking for a solid state amp that would be able to compliment my Woo Audio WA23 Luna. Cayin had announced the Soul 170HA a little bit before CanJam, so it was indeed on my radar to check out. On paper, it looked like a very interesting proposition with the flexibility that it offered. Plus, it looked good and that always scores bonus points and unabashedly a requirement in my book. So, if I love the amplifier, what can I say about it and why even do a review? It ought to get more exposure and I am hopeful that talking about it will do that. Even though I love it, I have a lot to say about it and not all of it is good. Before I get into all of that, lets just go through some of the details of the amplifier first.



The Cayin Soul is an amplifier that is made to drive various transducers. Its primary function seems to be based around driving headphones, where the front houses a ¼ inch output, a 4-pin XLR output, and a 4.4mm output, designed with IEM use in mind. However, it also has speaker taps on the back. For this review, I will not be evaluating the speaker capability of the amplifier. I may in the future, but presently, I do not use speakers in my office setup. The Cayin Soul 170HA has a couple of toggle switches on the front, one that switches between the three headphone outputs, 1/4inch, 4.4mm, 4-pin XLR. The other toggle switch is the impedance switch, Low (8-64 Ohm), Medium (65-250 Ohm), and High (251-600 Ohm), to cover your various headphone impedance. The amplifier is single-ended by design, so the XLR inputs and outputs are more for convenience purposes.

On the top front of the unit, there’s a VU meter illuminated in orange that wonderfully matches the glow of the tubes that flank the VU meter and other toggle switches. The switches are an RCA/XLR input selector, speaker/headphone output selector, triode/ultra linear mode selector, and finally a dynamic/soft selector. The first two are straight forward, but the other two are the more fascinating switches. I won’t go into too much detail about it, but you can read about those in Cayin’s own literature. Though, I will just say that the TR/UL mode switch gets a lot of use.

The basic gist of this switch is switching the KT170 tube to connect directly to the anode in triode mode, where the ultra linear mode taps the KT170 tubes to the output transformers, which provides higher voltage. What this does to the sound, I will take this verbatim from Cayin’s website: Triode mode “Tendering, smooth and elegant, holography with sharp image, suitable for vocals, string music, and mid-range focused genre” and Ultralinear mode “Open, bold, with great momentum, soundstage will open up, suitable for orchestral, OST, and music with a wide dynamic range. I would say that the general descriptions are pretty accurate and I will go back and forth between the two modes, depending on the headphones that I am using, the music I am listening to, and even what mood I am particularly feeling. It makes a pretty significant change to the sound presentation of the amplifier. The dynamic and soft toggle switch is much less significant and more subtle than anything. From Cayin’s literature: Dynamic is “Dense, fast and authoritative, prominent dynamic with contrast. Forceful and exciting quality.” Whereas Soft is “Relaxing, delicate and peaceful, reveal low-level details. Engaging and involving quality.” I’ll be honest, this toggle gets used much less. While I hear differences, especially in the midrange detail and energy, it’s not night and day.

Power output-wise, the Soul 170HA is a monster and capable of driving every headphone that I’ve tried on it and with ease. Thanks to the KT170 power tubes, the rated power output breakdown is as follows: 4-pin XLR outputs 12-18WPC, ¼ inch outputs 7-17WPC, and the 4.4mm outputs 2-4WPC. The 4.4mm works extremely well for IEMs or if you want to use a 4.4mm for your over ears. I will say that the noise floor isn’t completely quiet. Sensitive IEMs that I used, like Forté Ears’ Macbeth did exhibit a bit of hiss and tube noise. Putting the amp into triode mode does lower the noise floor, but realistically if you are looking for a black background for IEM usage, the Soul 170HA wouldn’t be my first choice. Using the Astell&Kern x Empire Ears Novus IEM, there was very, very little noise. That said, the amount of authority and power that this amp drives the IEMs to is extremely impressive. Once your listening to music, it’s almost a moot point anyway.



How Does It Sound

Sonic characteristics of the Soul 170HA, I would classify as a warm, neutral tuned without sacrifice of details. It’s a weighty presentation, but it’s not gooey or wet sounding. Especially in ultralinear mode, it’s highly detailed, has a big sound stage, has a rich midrange, and a hefty, authoritative bass that digs deep into the sub-bass region. You can further color the sound with a flick of a switch or two, namely switching from ultralinear mode to triode mode. With triode mode, the midrange becomes a little bit more prominent and musical sounding, adding a little bit more holography and just a bit more of what you would expect from a tube amplifier. Triode is proper tubey goodness while not getting too soupy. Dynamic range is lessened, but it’s far from lacking even detail or bass authority.

You can additionally customize its sonic characteristics with different tube options, too. Options to swap the GZ34 rectifier tubes or the 6SN7 driver tubes give you a lot of flexibility to shape the sound to your own personal preference. Unfortunately, the power tubes are not rollable, so good or bad, you are stuck with the Tung-Sol KT170s (for now). I spent a couple weeks listening to the amplifier in stock configuration with the JJ GZ34 and JJ 6SN7 tubes, but my current set consists of Mullard GZ34 and Apos Ray 6SN7 Reserve tubes.

For headphones that I’ve evaluated on the Cayin Soul 170HA, most of my listening impressions are on the RAAL 1995 Immanis, ZMF Atrium Open, and Meze Empyrean II. IEMs that I’ve listened to here at home include the Forte Ears Macbeth, Astell&Kern x Empire Ear Novus, FatFreq x HBB Deuce, and 64Audio A12t. Additionally, at CanJam So Cal, I also listened to the following on this Amplifier: Modhouse Tungsten DS, Caldera Closed, Atrium Closed, Susvara OG, and Susvara Unveiled. Mind you, any listening done at CanJam with those headphones was not extensive and I won’t be able to comment too much about them individually. I will just say that the Cayin Soul was able to drive them all pretty effortlessly and sounded great with each of them.

Treble

Soul 170HA has a little bit of treble roll off. It’s a warmer sound, but it’s not really dark or veiled. I still get a good amount of sparkle and air in the presentation. High frequency detail is still present and easily placeable, especially in ultralinear mode. Leading edges in attack are sharper in this mode. It certainly takes some of the edge off of some of the bite that some tracks might have. Tracks like “Hit the Lights” by Bensley or “Mirapolis” by Rone & Johannes Brecht. Despite its warmer tonality the amp is quite capable in overall resolution that it doesn’t feel smoothed over. This is certainly the case when I listen to the ZMF Atrium on the Cayin. Putting the amp into UL mode and medium or high impedence and the Atrium are just about as energetic as I’ve ever heard them in the treble. It’s not fatiguing, but there’s a lot of air and it’s the biggest I’ve heard them sound.

Putting the amp into triode mode rounds the treble even more, reducing the dynamism and edge a little bit further. It gives the amp a more euphoric signature in the treble. You do sacrifice a little bit of precision with a little bit more of a rounded tone in the treble, but air is still present. The lateral width of the soundstage and the sparkle does shrink a little bit in triode mode. I think this is actually helpful specifically for a headphone like the Meze Empyrean II. I find that headphone has a lot of lateral width, but forward depth is not as big. The triode mode makes the oblong soundstage of that headphone more circular. I also think there’s a little bit more lower treble energy in the Empy II that benefits pretty significantly from the sonic characteristic of the Cayin.

With the RAAL Immanis, I end up favoring using the ultralinear mode more, though not exclusively. There is a certain magic that I find with his pairing in the upper frequencies. Treble sparkles and is highly resolving of micro details and air. The Immanis sounds quite expansive. Upper harmonics and overtones prevail while listening through the Immanis. In live recordings especially, the size of some of the halls, notes and sound echoing through space is more tangible than I’ve experienced before with this pairing. Conversely, studio recordings have a reduced sense of the additional overtones and harmonics and sound unsurprisingly smaller and more “room-treated.” No other headphone pairing with the Cayin was able to present that size perception better.

I really like the treble character of this amp. It’s one of the many appealing aspects of the amp. It is never fatiguing to my ears. Detail is present, but the treble still exhibits weight and texture. Despite the coloration, it is still surprisingly revealing. I do feel like I got a bit of treble energy extension and detail with the Ray 6SN7 Reserve, too. Overall, though this amplifier isn’t going to be for those who are looking for neutrality, incisiveness, and a colorless presentation.



Midrange

Flexibility is the name of the game in the midrange. I think the midrange is really lovely on the Soul, though it’s bested by other tube amps, like the Woo Audio WA23 Luna. That amp I think has one of the best midranges in the market. The Cayin in triode mode though, has a lushness and euphoric nature that the midrange takes on. The tonality brings it closer to the WA23 and I think with the right tube combination, it can close the gap even further. Holography certainly is improved with triode mode, too. The shift in tonality just brings a bit more attention to the midrange. It doesn’t simply push mids forward making them intimate. No, in fact, they just get deeper in the sound stage in triode mode. This has been a really good choice for my chamber music, both vocal and instrumental. The piece, “On the Nature of Daylight” by Max Richter is a great example of this. The cellos sound lush and tangible. My a capella music, too, like Home Free’s cover of Johnny Cash’s “Ring of Fire.” The all-male group has some really lovely harmonies that in triode just sound a little bit sweeter.

Where I end up preferring ultralinear mode’s midrange is on big orchestral pieces or big band albums and songs. MIchael Buble’s early albums, “Call Me Irresponsible” & “It’s Time” retain its grandiose scale and I feel that instrument separation is better. The larger soundstage in ultralinear mode just help place more space between everything. Michael’s vocals are very squarely in the middle, but the band’s instruments surround him, both on the sides and behind him. Hans Zimmer’s score on “The Dark Knight Rises” album also has the same effect.

An aspect that I really like about the Soul’s midrange is its inherent body. It’s not thick per-se, where thick mids quite often can feel overly hefty. Especially in vocals it can just sound excessively throaty. The note weight just feels very well balanced. It’s well textured and also not overly emphasized. I find both male and female vocals just sound engaging on the Cayin Soul. With the right headphones, mids are also very well articulated, exhibiting very, very good instrument separation. Vocals and various instruments retain each of their individual character and never feel congested.

Bass

Powerful. Controlled. Articulate. Remarkable. I don’t profess myself to be a bass head, but I still need good bass to have a well-rounded, engaging listen. The Cayin Soul provides that better than any other tube amp I’ve tried. Envy was close, but a little bit thicker in the bass presentation and the sub-bass is just a little bit less prominent. That’s when comparing ultralinear mode to the Envy. I think the triode mode actually brings it more in line with what I remember from the Envy’s bass, a little bit more rounded and a bit less sub bass energy.

With the ZMF Atrium Open, I have never heard the headphone become more aggressive in the bass than I have with the Cayin. Ultralinear mode and high impedence, the Atrium comes alive and energetic. There’s a level of punch that and slam that the Atriums took on that I’ve not previously experienced. Every track that I’ve tried simply just attacks and hard. It’s not pillowy or bloomy, in fact, I find it more articulate, while more dynamic. It’s quite something and makes me interested in seeing what the Atrium Closed and the Caldera Closed are capable of on the Soul. I’ve heard some say that it can be too much of a good thing, but I’m here to say otherwise. Granted, you can tone down the energy with a flick of one or two switches, putting it in triode mode and/or lowering the impedence switch down. It’s still impressive even with these settings.

With IEMs through the 4.4mm connection, bass is equally improved through the Soul. It is more powerful and more prominent than any portable solution that I’ve heard to date. A&K x EE Novus growls aggressively with control and authority while reaching sub frequencies that will massage your brain. I’ve never felt the inside of my skull vibrate so prominently. The very same is the case with the FatFreq Deuce. These two sets would please the bassiests of bass heads on the Cayin Soul.

Bass on the Immanis, I’ll lead with this… this is one of the reasons why I was so excited about the Cayin when I first heard it at CanJam in the Bloom Audio room. I vividly remember the bass that I had gotten with the WA23 paired with the Immanis and the Cayin did all of what the WA23 did with the bass, but just became punchier, harder hitting, and was more textured, which was what surprised me most. As I tried tracks like, “Give Life Back to Music” by Daft Punk, it was immediately apparent that the Cayin elevated the bass experience. Again, it wasn’t really that the bass became thicker and more bloomy, rather it just articulated more and had more weight. It didn’t just have more weight, but the control it has with the Immanis at the same time.

With the Meze Empyrean II, I also found the bass to be the best I’ve heard them sound. Meze has a mid-bass boost and the Cayin doesn’t overly emphasize it further, making it bloomy. The Empyrean II are rolled out a decent amount in the sub-bass region and the Cayin I felt brought a little bit of that back. It’s not a significant change or automatically make it a linear headphone in the bass, but it did give it a little bit more energy down low.



Soundstage

I touched on this earlier, but wanted to revisit this on its own. As I said earlier, depending on the mode you choose, you get larger-sized sound stage (ultralinear) or you get a slightly narrower image, but you gain forward depth (triode). Overall, I find that both modes have their use cases, but realistically, the soundstage is fairly large in its stock configuration. Adding the Apos Ray 6SN7 Reserves did expand the soundstage a decent amount, too. So depending on the tubes you roll, you can get even bigger stage (or smaller, if you choose). However, the Atriums certainly sounded the largest that I’ve experienced on the Soul. As I mentioned with the Meze Empyrean II, I preferred the triode mode for it’s reduced lateral width, which even out the soundstage more. On the Immanis, again I ended up preferring ultralinear. I do think there are going to be other amps that stage even larger, especially with the right tubes, but I suppose this is one of the downsides, relatively speaking, of the amplifier.

Miscellaneous Bits & Quirks

The Soul 170HA comes with a remote control for volume. I always appreciate remotes when they are included and miss them when they aren’t. The Soul’s remote is solidly built out of metal, with three buttons, mute, volume up & down. No battery is included and the type of battery required is a single CR2032 disc type. The volume adjustments with the remote are just a tiny bit larger in increments than I’d prefer, but that’s a minor gripe that’s negated largely because of the convenience of simply having a remote. The IR sensor is also cleverly built into the center of the volume potentiometer, too.

I also have to point out the weight of the units. The combined weight of the amplifier and the separate power unit is about 80lbs. Stacked up together they also take up a decent amount of cubic real estate. Speaking of the separate power supply unit, there are actually two umbilical chords with Lemo-style connectors. One provides higher voltage while the other provides lower voltage, which I believe coincides with the 4.4mm output, I could be wrong. Pretty interesting design choice to separate them.

Both the amplifier and power supply unit generate heat. Both are pretty warm to the touch, but not hot. The component that seems to emit the most heat are the KT170 tubes. The driver and rectifier tubes also are hot, but seem slightly less so, compared to the power tubes. However, the overall unit runs a bit cooler than my previous amplifier, the WA23 Luna. Realistically, this will heat up your room just like almost every other tube amplifier.

Another relative gripe to note, on more sensitive headphones and IEMs, I can pick up wireless/cell digitized noises, as well. It’s not just the hum or hiss from the tubes, either. So that’s something to note as a bit of a quirk. I also had to add isolation feet to the amplifier as well. Since it sits directly on my table top, vibrations and bumps would transfer through to the chassis and tubes and heard headphones (when no music or it was playing quietly).

I also am mildly disappointed that there is no preamp capability with this amplifier. The WA23 Luna I had prior did and while it wasn’t something that was used often, having the option was certainly really nice, especially as I searched and possibly still search for a solid state. However, I’m a realistic and know how versatile this amplifier already is, I know there’s gotta be some limitations. It’s really hard to imagine how much more they could make it do. So I digress.



Wrapping Up

At the beginning of this review, I claimed they succeeded in making a product that is bold and creates a statement. If you happened across my review of the WA23 Luna, you know that I professed that amplifier a statement piece. To borrow the term once again, the Cayin Soul 170HA is yet another wonderful statement piece. It’s eye-catching, it’s bold, and it’s a conversation starter. With the Cayin Soul, however, it is a bit more recognizable and traditional as a piece of audio equipment, versus the WA23 Luna. It’s no less striking and no less unique, though. It doesn’t just look good, it doesn’t just sound good, it also feels good, too. Everything has a premium feel, from the remote, the switches, the connectors, the chassis, including the wooden panels, VU meter, volume potentiometer, and even the faraday-like cage that protect the tubes.

The sound itself is powerful, refined, engaging, and without fatigue. Subjectively, every headphone and IEM that I’ve put on the amplifier has sounded better than I’ve ever heard them before. This is not a neutral amplifier, leaning a bit more on warmer side, but it still highly resolving across the frequency range. There’s also texture aplenty. It’s not the be-all-end-all in sheer sound grandeur, but you do have a lot of flexibility to cater the sound more to your liking. I do hope that eventually we will be able ot roll KT170 tubes, but for now there’s still lots of choices with the 6SN7 and GZ34 tubes. The amplifier still gets massive kudo points for its flexibility and versatility.

The Cayin Soul 170HA has been wtih me now for over a month now and I am just as eager to listen as I was when I brought it back from Can Jam (a big shoutout to Andrew DiMarcangelo and the entire Bloom Audio team). Again, I was not looking for an amplifier to replace the WA23 Luna, but Cayin certainly had something to say in this regard. It will not be everyone’s first choice, some will prefer the WA23 over it, others will still gravitate towards the Feliks Envy. However, for this guy, personally, I’m sure I leave you with no doubt where I stand. Regardless, this statement piece deserves to be talked about and considered if you are looking for a top end tube amp. As I wrap this review, I sit here listening to it still. Today alone I’ve probably clocked about nine hours of listening on the amp (one of the benefits of working from home). I can tell you, I am eager to continue the same trend tomorrow and the next day, and so forth.

(Here’s a picture of me enjoying the Cayin Soul amplifier for the very first time in the Bloom Audio room)

Forte Ears Macbeth

I think that everyone can relate to the dichotomous relationship that I have with IEMs. I can love one thing about an IEM, but not love, feel indifferent, or even despise another aspect or multiple aspects. I can even love lots of things, but have issues with just one. Sometimes… truthfully, often… those IEMs leave my possession rather quickly. I am a minimalist by nature, so I don’t want nor do I feel the need to keep something if it’s not getting used much. If something bothers me, I am less inclined to use it. That said, I’m also a realist, so I also know that life is all about compromises. I know that there is nothing that is perfect, nor is there going to be anything that I love every aspect of. This is congruent with my experience thus far with Macbeth. I’m sure many people share that sentiment, but how close does Macbeth get to perfection? Pretty close, but more on that down below. I think what I ultimately am secretly looking for is an all-rounder. With IEM’s, especially top of the line IEM’s, I am on the hunt for one that has the least compromises and the question I contemplate, “could the Macbeth be such an IEM?“ It certainly is in the running. Regardless, Riccardo, Forte Ears, AND Macbeth deserves additional visibility, emphatic enthusiasm, and accolade, hence my eagerness to write this review.



Let me give a bit of background. Macbeth was only a tiny blip on my radar prior to heading to So Cal Can Jam ‘24. I certainly was curious to hear them, but there were others that were on the top of my list to listen to. Among those IEMs that were must-listen were the Subtonic Storm, PMG Audio APX SE, Astell & Kern / Empire Ears Novus, Cayin Amber Pearl, Oriolus Trailii / Ti, FatFreq Grand Maestro Anniversary Edition, and Unique Melody Multiverse Mentor. There were others that were on my list, but I didn’t “Star,” meaning that if I didn’t listen, I wouldn’t really care… Macbeth was one of them. However, it was getting a lot of talk on the Watercooler thread that I couldn’t entirely ignore. They still weren’t super high on my list, but it kept creeping higher up.

Then, the day before Can Jam came and I went to lunch with a lot of the Watercooler folks. Riccardo Yeh, Forte Ears founder, was among our party. As Macbeth was still not extremely high on my list, so as an ignorant individual, I had no idea who he was at the time, until after we were all done eating and Riccardo brought two Macbeth over to the table I was seated at, so a couple of people could listen to them. A couple of them listened and while we were not seated long, but their initial listening impressions were quite positive. I didn’t listen then and figured I’d listen the next day at Can Jam.

It was not until late on the first day that did I finally make my way over to Forte Ear’s booth and sit down for a listen. I was instantly incredibly impressed. I listened to small sections from about 8-9 different songs I am familiar with and I said a few words of praise and things that really stood out to me, praised Riccardo on a marvelous listen, thanked him for his time, I set Macbeth down and left the booth. As I finished out the day, the question would come up asking what I had heard and what was good, I’d rattle off things that stood out, but Macbeth seemed to be in every single one of those conversations. It was one of two things I could not stop talking about. Even long after the first day closed, I was still talking and thinking about the IEM. The next morning, my friend and I got breakfast and could not stop reeling about what we were hearing at the show and Macbeth was, again, one of those. We got to Can Jam and were there at the entrance early just standing around when we started having the conversation with Warren Chi and the Macbeth, unsurprisingly, came up again. We went in a little bit before the show to chat with Riccardo and have a proper listen to Macbeth, both on the stock cable, and with the upgraded Ambition cable. Warren warned, once you hear it with the Ambition cable, you can’t unhear it. This is 100% true. He also made a singular track recommendation called, “Adam and Eve” by Cameron Graves to listen to, which I took heed to. I will talk more about that song later in the review, but suffice it to say, it is an extremely good track to use to test. Incredible. Just incredible. I just couldn’t believe how good this IEM was. Hell of a way to start the 2nd day of Can Jam. Once again, I could not stop talking about it through out the entirety of the day. This time, my tune changed a bit and it had become the “Standout of the Show” or “Star of the Show” for me.



The night after the show, my friends and I continued gushing about it. The next day, I had to reach out to get one here. Andrew at Musicteck obliged my inquiry and about a week later, it arrived at my home. I let the set burn-in for close to a week, listening off and on, but truthfully, I don’t think this set needs a whole lot of burn-in time, especially since there’s not a dynamic driver.. Let’s talk about the different aspects of this IEM.

*Just for additional reference, I listened to Macbeth off of several different source chains — Astell & Kern SP3000T, iBasso DX320MAX Ti, HiBy x Evangelion Limited R4, Questyle M15 connected to both my iPad and my iPhone, and also my desktop rig, Holo May KTE + Cayin Soul 170HA.

Bass

Bass on this is spectacular. It is articulate, it is punchy, it is very well textured. Songs with a heavy bass and sub-bass prominence, still retain texture. Midbass kick is well articulated while retaining lots of note-weight. Additionally, wIth the mid-bass it strikes a good balance of heft without bleeding into the lower midrange. One track that can easily show bloat into the midrange is the cover of “The Sound of Silence” by Geoff Castellucci. He is a bassy singer and the way the track is mixed, puts even more emphasis on on the low end. On some IEMs his voice can sound overly bloated and congested. That’s not the case with the Macbeth. This is not an overly bassy IEM, but it’s presentation in the bass region is still quite prominent and certainly is not bass-light. Sub-bass depth is quite an impressive. The song “Lies and Deception” by Infected Mushroom starts out with some really fun sub-bass “whomp, whomp, whomp, whomp.” It’s not a boomy bass line, rather it’s sub-bass focused. This can sound too pressurized and lose out on detail and texture, but on Macbeth it strikes an exquisite balance while achieving ear vibrations without muddying the bass texture. It’s not the last word in bass authority, but is still really, really good.

Just for kicks and giggles I do like to throw the Macbeth on the Cayin Soul 170HA to listen that way. Bass becomes heavier and more bloomy, but it is a whole heck of a lot of fun. It brings macro dynamics to Macbeth that is just undeniably fun. Bass-heavy tracks kick like a mule on steroids that bring a silly grin to my face. Songs like “Kill Jill” by Big Boi, “redrum” by 21 Savage, or “It Goes In Waves” by Inzo, Blookah, and Align are tracks that I just have a ton of fun with in these instances. Hans Zimmer’s “Why So Serious” from The Dark Knight movie soundtrack is another common sub-bass torture test that is good to showcase Macbeth’s bass strength.



Midrange

I will lead with this — Midrange on Macbeth is some of the best I’ve heard on any IEM. Tonality, texture, timbre, articulation… all of it is marvelous. My previous midrange favorite was the Canpur CP622B and I don’t think that IEM is far off from Macbeth, but I think Macbeth edges it out. I think tonal quality and texture the two IEMs trade blows, but where I find Macbeth pulls ahead is in midrange holography. It is easy to pinpoint placement for vocals and instrument position within the sound stage. String instrument timbre is great. Bowing and piccicato on strings both have a good weight to the sound. Horns and the brass instruments also have a great balance in their blare without feeling too shouty and thin. With headphones with excessively recessed mids tend to make the strings and horns sound thinner than they ought to. “Tchaikovsky: Symphony No. 5” by Pittsburg Symphony Orchestra showcases both the brass and string timbre. Pianos also sound beautiful across the entirety of the keyboard. Warren’s recommendation of “Adam and Eve” by Cameron Graves highlight many, many of the strengths of the midrange. There are instances, especially during the piano solo rift where some of the notes could potentially be too pingy, but it doesn’t happen. Each note in each of the octaves seem quite evenly emphasized. The saxophone solo that follows is equally mesmerizing and engaging. The sax has such a sweet, rich timbre as it takes center stage. There is so much to like with this track, from impactful bass to detailed, articulate treble, but again I think for me the midrange really is the showstopper in this track.

Vocals also are some of the grandest I’ve heard on an IEM. I use several tracks from chamber groups like Voces8, Chanticleer, and a more pop-style a capella group, Voctave as a baseline. The emphasis on individual ranges, from bassists, tenors, altos, to sopranos, is well balanced. There maybe a tiny little bit of a recession that creates a broader sound stage, but I do think it strikes a really, really nice balance without creating a distant-sounding nor an excessively intimate presentation. I also don’t experience any shoutiness especially in the typical vocal range, which I am particularly sensitive to.

However, as much as I love the midrange and stand by my position that is one the best I’ve heard, I will say that I’ve come across a quibble with it still. There are a couple of instances, for example in the song “Creep” by Radiohead, there is a bite to the treble that is quite strong. Sibilant tones are very peaky in this particular track and this doesn’t manifest in most other song I’ve listened to. Generally, I do find this track to have more energy in the plosive consonant areas, but this has not ever been excessively peaky in any other IEM or headphone I’ve listened to this track with, just with Macbeth. Granted it’s nearing a frequency area where I tend to be sensitive to, 5-6kHz, but falls just outside of that bound. It’s a strange peak that only manifests itself in a few songs, as other vocal-centric songs don’t have over-emphasis in the plosive consonant range. Additionally, the rest of the midrange, all except this one upper-mid treble sharpness, and maybe BECAUSE of this in some regard, still are some of the best that I’ve ever experienced on an IEM.

With how much I like the midrange, as a whole, on both the Macbeth and the CP622B, I have to assume the biggest contributing factor to be the mid-focused bone conduction drivers. It seems to be the same configuration as the Canpur, in this regard, which makes sense, since I enjoyed hte mids on the CP622B so much prior.



Treble

Treble is outstanding. It’s crystalline in clarity. I found the treble to be exuberantly detailed without harshness or graininess ever. Overall, the treble resembles Elysian Annihilator clarity with a touch of treble energy rolloff. As I recall, Annihilator had more excitement that could be more fatiguing in the long run. If some found the Elysian Annihilator’s treble fun but a touch too much, I think this might be a set that really needs to be looked at. On the Macbeth, there’s a lot of airiness and the general treble tone is really, really good. Hi-hats and crash cymbals have just enough energy for my ears. “Chocolate Chip Trip” by Tool is one example where it showcases a drum kit’s treble timbre quite well. It’s a really nice balance between the bass kick from the kick drum and the splashes from the cymbals. The articulation is top notch. Air extension is wonderful on this IEM and it further enhances to its wonderfully expansive spatial presentation. There is a really good balance of sparkle and sizzle to the rest of the frequency tonality.

Also, it’s worth noting that on the wrong sources, the treble energy can be a bit excessive. Treble on something like the HiBy x Evangelion R4 was too strident on some tracks. The Questyle M15 was also one that I would point to as possibly a little bit on the harsher, edgier side. The Astell & Kern SP3000T and iBasso DX320 Max Ti were both just fine, as was my desktop system with the Cayin Soul 170HA.



Soundstage & Holography

I’ll lead by saying this, soundstage and holography is one of the biggest strengths of the Macbeth. It will be dependent on the source you are using again, but what I found that even on the least expansive source, the HiBy R4, Macbeth still sounds large. The depth and accuracy that I hear from the Macbeth is top notch. I can’t say for sure it is the most open-sounding IEM, but there are many times the image appears thrown beyond the bounds of the IEM itself. It’s also one few of the IEMs and headphones that I can easily place slight movement of singers and instrument players. Depth and layering is also handled aplomb. Separation between soloists and instruments or backup vocalists is easily delineated. On the track, “Both Sides Now” by Chanticleer, it features a tenor soloist with the rest of the men’s chamber group singing harmonies surrounding him. Additionally, you also get a good sonic image of the size of the hall they recorded in with its expansive reverberation. Another song from a chamber group Voces8 and their track, “Lauridisen: O Magnum Mysterium” allows you to hear placement of each of the eight singers with precision, but the trailing tones echo through the cavernous hall so gorgeously.

Large orchestral works are exquisite on the Macbeth. The album “Britten: War Requiem” by the London Symphony Orchestra was one that I listened to in its entirety and was just constantly floored at the Macbeth’s handling of it. Typically this is something I would just opt to listen to my headphones. Whether that’s classical or modern orchestra works, such as movie soundtracks from the likes of Hans Zimmer or Ludwig Goransson, the Macbeth shines. Ludwig Goransson’s soundtrack from “Tenet” tests the limits from top to bottom of an IEM and Macbeth handles it in all its dynamic glory. Macbeth has the frequency range to support the synthesized ultra low frequencies those modern composers like to use to support the grandiose soundstage necessary for the instrument ensemble.

Back to the track “Adam & Eve” by Cameron Graves, the sound stage elements in this track are also quite impressive. You get a good sense of where each of the instruments in the band are coming from along with stage depth. Hearing subtle background noises, even as at the beginning of track while the piano soloist riffs and vamps, including adjustment and setup noises come from very specific and placeable points in the sonic image. It’s quite something (and thanks again for the track recommendation, Warren)!



Aesthetics & Comfort

Macbeth’s shells are medium/large in size and are smooth polished 3D resin shells. The faceplates are rhodium plated and hand painted. I must say that from initial pictures I was not all that impressed with the appearance of them, but once I got to see them in person, they really struck me as beautiful and bold. Even before listening, seeing them quickly changed my opinion of their appearance. The attention to detail on the faceplate is remarkable. The blood red background is not simply a solid color, there is metallic, glittery texture to it. The different colored jewels in the crown are subtly accented. Several swords flank the crown. The words Macbeth (left) and Forte Ears (right) are inscribed on opposing shells in tiny print at the base of each crown.



The 3D resin, while it’s a material that is easily found on some of the cheapest IEMs and can be considered cheap, I think is still a good choice for the shell because it makes the overall feel and weight of the Macbeth among the most comfortable I’ve had in my ears.

I would be remiss if I did not make mention of the packaging for the Macbeth. Everything about this IEM has been well thought out, which includes the package. With so much attention to detail on the box and with each of the included accessories, the culmination of it all just screams, “theatrical!” and “opulent!”



It’s all well and good to look spectacular, but my biggest concern with IEMs comes down to comfort. If I can’t wear an IEM for more than an hour, let alone for a couple+ hours, the IEM does not belong in my collection. Thankfully, Macbeth is really comfortable. This statement comes in three parts, the shell size, the nozzle sizes, and the stock cable all put no pressure on any part of my ear. The shell sits comfortably and doesn’t have any weird bumps that put unnecessary pressure on my ears. The Macbeth don’t need deep insertion, and even with them not deeply inserted, they don’t stick out obtrusively. Realistically, I’ve gone several hours with them in my ears and took them out with zero ear aches or sensitivity. The included cable wraps nicely and is light enough to effectively be forgotten as I wear them.

Eartips-wise, the included ear tips, the Eletech Baroque are some of the most comfortable IEM tips I’ve used. I do think they also are a great pairing with the Macbeth. I ended up just slightly favoring the Divinus Velvet Wide Bore tips. I just find that it thickens up the bass just a bit more which gives me the extra heft I end up preferring.



It’s Not All Roses

As I said in the beginning, nothing is without its faults and the Macbeth is no different. So, what do I not love about the Macbeth? Bass, while quite incredible, is not the hardest hitting IEM in the market, the Velvet Wide Bore help with heft, but dynamics, slam, and attack could be just a little bit better. Macrodynamics are also not the be-all-end-all. Low end texture and articulation is great, but I feel like the timbrally characteristic could be a touch better. This is a minor quibble, but it’s worth mentioning. In fact, I don’t think this is a fault of the BA bass, in fact, it’s one of the most incredible implementations of balanced armatures for bass; rather I think it’s a tuning choice with the bass shelf. Again, for emphasis, it’s one of the least-BA-sounding implementations I’ve come across and rivals some of the best dynamic drivers.

The midrange, while presentationally it is mostly tuned beautifully, but there are a couple instances where it can be pretty sibilant as I outlined prior. Still, I think those are track specific instances and by and large it is a wonderful, good balance and tonality in the midrange. Timbrally the midrange is still some of the best I’ve heard.

I also don’t love that I’ve heard the Macbeth on the Eletech Ambition cable, which takes everything that I loved and gushed about here and expanded upon them almost exponentially. It’s not a necessary addition, but it is quite something to hear just how much better the Macbeth can sound. I also wonder if it would further exacerbate the primary area where I feel could use a bit more refinement, which is the treble.



Wrapping Up

So, does Macbeth work for me, personally, as an all a rounder? This is going to be a tough one to answer and I can’t say definitively. It does almost everything so right, but (there’s that word) I still just wonder how impactful the upper mid-range sibilance is going to be for me in the long run. I really don’t want to diminish the fact that Macbeth does just about everything else supremely well, so I’ll just keep evaluating whether that compromise going to be small or large in the grand scheme of things.

Macbeth is a unique proposition combining the likes of some of the most talked about IEMs presently on the market — it offers exquisite Elysian Annihilator style treble, Canpur CP622B-esque midrange, while besting either of those sets in it’s bass. It is remarkable and absolutely deserves a place among the top of the line IEMs on the market to date. My take is that it has probably the best midranges I’ve heard on an IEM thus far, despite that one odd peak; there is an expansive and engaging character in here. Bass is remarkably done and the proprietary tech/tuning Riccardo developed leaves little room for improvement. By and large the treble is wonderful and among the most resolving sets out there. Riccardo has a flair for theatricality and the Macbeth makes a grand, grand opening act for Forte Ears. This makes me eager, if not a bit leery and skeptical, of what is in store from Forte Ears. Will the Macbeth be Forte Ears ”magnum opus“ or will it just be a bold first act that leads to greater subsequent acts? Either way, it’s a fantastic set that needs to be heard as I think this could very well be many people’s choice as an all-rounder. Bravissimo, Riccardo. Bravissimo.

Statement Piece - A stunning statement piece can create drama or be a focal point. The point of it is to capture interest and stand out in your space.

The Woo Audio WA23 Luna is a statement piece, through and through. It draws attention. Its design elements stir up discussion. One can’t help but see the WA23 and immediately give pause. Its looks are unique; moreover, one of the most fascinating design elements is its duality. The color scheme of a solid black chassis and gold accent trim is exuberant yet refined. It’s both subtle and bold. It’s anything but a subtle piece of audio gear, but its design practically screams stealth. It’s so grandiose without being gaudy. It’s classy looking. It is one of the most tastefully designed pieces of gear ever to hit the market. For a piece of audio equipment, that’s well and good, but if it doesn’t function or perform well, then it’s all for naught. Thankfully, the WA23 doesn’t just create a stir with its aesthetics, it has the functional performance to back up its artistic design.

Typically, I lean heavily towards solid state amplifiers. I want dynamic range. I want punch. I want detail. All those things are easily found in solid state amplifiers without hardly any sacrifices. Moreover, all those things can be found without breaking the bank. Solid states that can drive difficult-to-drive transducers are in abundance and at affordable price points. The headphone amplifier world in previous years has been akin to questions like, “can it drive the Susvara?” In more recent years, it’s been refined to, “how well will it drive the Susvara?” Finding a solid state to be able to achieve that was a rarity, a crowning achievement, even. Forget about getting a tube amplifier that could drive such difficult headphones, back a few years ago. Nowadays, solid states that can drive the illustrious Susvara, among other difficult headphones, are a plenty. Tube amplifiers have made monstrous headway, and we now have some top-tier ones, like the Feliks Audio Envy, Cayin HA-300B mk2, Woo Audio WA33 SE and the EE, to name a few. And now also the WA23.



The WA23 Luna is certainly enough to drive the Susvara and to volumes louder than I am comfortable listening to, and it can do so beautifully, to boot. However, an important note: this will depend on how much signal voltage you are sending to the WA23. Gain staging is important here and if you’re DAC is feeding a standard 2v signal, it probably will not be enough to drive Susvara to a sufficient volume, or other hard-to-drive headphones. The Holo Audio May does just fine with the 5.8v XLR output. I have the WA23 set to low gain with the volume dial set between 12-2 o’clock, depending on the tracks. For extended listening periods, this is where I am most comfortable. I can push it to about 3 o’clock, but for longer sessions this is too much. For more leisurely listening, I might nudge it closer to 11 o’clock on the volume knob.

I’ve heard a lot of amplifiers in various capacities, but the headphone amplifier I’ve had the most extensive time with is the Ferrum Oor prior, so most impressions or thought comparisons are based off that.

I have tested pre-amping chains with the Oor and the WA23. Using the Oor as a pre-amp to the WA23, I did not particularly like what the Oor did to the sound. You really don’t gain much from this set up. With the WA23 as a pre-amp certainly adds some of the coloration and characteristics to the Oor, but ultimately, I did not find that the WA23 & Oor combination was a good fit. Most of my reasoning with this is because the WA23 outperforms the Oor in just about every aspect, which I’ll explain more in my impressions of the WA23. I could possibly see very specific use cases where it could be useful, but all in all, having the Oor in the chain did not improve the listening experience at all. The WA23 is just a better amplifier all together. I certainly will be playing with the WA23 as a pre-amp more when it’s finally my turn to have the Zähl HM1 in house, but a while off now.



So, how does the WA23 sound then? These words come immediately to mind— Beautiful, lush, authoritative, engaging, and effortless. Buckle up though, I’ve got a lot more to say.

When I first began listening, the first thought I had was, “wow, that is quite powerful.” My initial concern that the WA23 wouldn’t be sufficient enough for the Susvara was put to rest in the first 10 seconds of my first listening track. The first test track I used was Daft Punk’s “Give Life Back to Music.” The opening sequence of this song gives a good sense of how much impact it can have. As the song continued, the complexity of the jam-packed layering, really show the resolving capabilities of the amp. That was a fun introductory experience for this amp. I had every intention of switching tracks after the first track finished, but as the next song began to play, I remembered there were things that I wanted to hear there. Track after track played and before I knew it, I ended up listening to the entire Random Access Memories album. One of my favorite tracks on this album, however, is, “Giorgio by Moroder.” Starting at the 6:23 mark, there’s intricate details stacked in drums, synth, guitars, melodic line, and vinyl scratching. Attacks and decays of the various sound elements during this portion are a whole lot of fun. No matter how busy this sequence got, the sound was clean and effortless. The layering remained deep while well defined. The WA23 resolved all the details succinctly and, surprisingly, with more texture and body than I was used to. At the 7:45 mark there is a series of drum hits are blazingly fast, which can appear a bit muddied by all the added track layering, but the prominence here of the drum passage with accompanying thumps and cymbal splashes were never lost, once again, really displaying the effortlessness of the WA23. I will quickly add another favorite track of mine from the same album, “Motherboard.” Various instruments, like strings, flutes, and acoustic guitars, are interspersed with synth and drums that give so much body and life to the song that similarly impressed me.

Shifting gears away from Daft Punk, another track I listened to is Tool’s “Chocolate Chip Trip” from the Fear Inoculum album. This track, while less melodic than the tracks mentioned above, has several elements that flexes this amp’s strengths. At the beginning of this track there are wind chimes that are played in a bit of random sequences. They seem to hit and linger, ringing in a manner that exudes realism. I believe this perceived realism is due to the 2nd order harmonics from the tubes. The tiny bit of overtone series the tubes add, sweeten the sound of these chimes in a way I’ve not heard on any solid-state amp I’ve tried. Additionally, the various chimes come from different directions and distances in the sound stages. Another aspect of this song I really enjoy is the focus on Danny Carey and his drum kit. The splashes, slaps, hits, and kicks are distinctly tactile. There’s industrial sounds and synth that float back and forth through the left and right channels. The bouncing back and forth is persistent throughout, but amongst all the busy passages, it can get lost. Especially with the kick drums and crash cymbals, the panning and succinctness can often get lost. Not so on the WA23.

A track I’ve recently discovered that has made it into my regular testing/listening rotation is “Antecedent” by The Omnific. This progressive rock band is comprised of two bass guitarists and a drummer, a bass-head’s delight, for sure. There’s depth and heft inherent, but there’s also a ton of speed to the sound, as well. Also, the bass guitars have some effects pedals that are just really cool sounding. The note separation, especially in the lower registers, often blend together on lesser capable electronics or transducers. The combination of the rich timbre and transient agility of the WA23 pair marvelously with this track. The space between notes and drum attacks is palpable. Each strum and pluck of the metal bass guitar strings are almost felt as much as they are heard. No matter how quick, each onset is tangibly audible, and reverberate as such. The rest of the album, Escapades, is just as engaging and if “Antecedent” is right up your alley, listen to the rest of the album, too.

I’ve described a couple of parts of the sound reproduction of this amp already, gushing about the details and transient response, but one reoccurring standout aspect you might have picked up on certainly has to be the tonality, texture, and tactility of drums. The topic of tonality and tactility being at the forefront, lead to one of the most important aspects of my music enjoyment that I want to talk about next — Vocals.



I’m a classically trained vocalist. I sing semi-professionally in various forms, including mens chamber groups, large chorales, and church choirs, quartets, and solos. I say this only to illustrate that vocal representation is something I pay a lot of attention to. Classical, opera, choral, a capella music are types of music I thoroughly enjoy. Not limited to just those, though, vocals intrigue me in every genre, but I do have a soft spot for live music and live-recorded music. A go-to track that I use often comes from a vocal group called Voces8. From their album Eventide, the track,” The Seal Lullaby,” composed by Eric Whitacre, has the eight singers spread distinctly around the listener. Each of the singers' positions in the sound space are discernible, with each of the vocal parts coming from very specific directions. Each of their vocal timbres are well represented on the WA23. The harmonies and overtones that linger in the hall reverberate sublimely. The octet is also accompanied by a harp, which sounds heavenly and so, so sweet. It’s a beautiful song made even more beautiful by this amp. Other tracks on this album also have other instruments, like a saxophone in the track, “Quanta Qualia” that sounds elegantly smooth.

Keeping with the acapella theme, a mens chamber group that I love listening to is Chanticleer. Their rendition of Franz Biebl’s “Ave Maria” from their A Chanticleer Christmas album is one of my absolute favorites, partially because I’ve heard the group perform it live and because I’ve performed this song many times myself in the mens ensemble I sing with. It features four part mens harmony and also a separate mens trio, so seven separate parts. At the beginning of the song, the main group sings the chant in unison on the left half of the stage, but as they finish, on the right, you can hear a couple of quiet footsteps from dress shoes as the trio steps into place. These footsteps are pinpoint accurate where you can hear them on the right side at about the 2 o’clock position, but the reverberation of the steps of the hall just echoes as the trio begins to sing. It is quite marvelous. Each individual vocal part is noticeable as it is sung, but then just float away into the cavernous hall they recorded in. I’ve listened to this track probably a thousand times and the realism I get when listening on the WA23 is as close to the live performance experience as I’ve ever gotten, emotion and all.

I also must make mention of Geoff Castellucci’s cover of “Sound of Silence.” This bass vocalist has rich, deep vocals and a timbre that I really is impressive by itself. He layers his own harmonies with his own voice, so the timbre match is especially pleasing. However, notably, the sub-bass presence in this track is quite extreme. The depths will properly pressurize your headspace, testing the limits of the amplifier and transducer. The WA23 effectively took this track and said, “here, hold my beer…” keeping up with the demands and added texture and proper nuanced details across the board. However, just as impressive is the more intimate moments where I could more tangibly hear the press and lift of his hands on the piano keys at the beginning. Geoff’s plosive consonants, “t” and “s” and the softer “d” and “b” sounds also each had a touch more air and texture.

I will also quickly mention, I really enjoy listening to Billie Eilish on the WA23. Her intimate vocals really are markedly more engaging on this amp. And the macro dynamics of this amplifier really lend itself to this. I really like the track, “bury a friend.” Intimate vocals, authoritative bass, deep sub-bass, and plenty of opportunity for each element of the track to get lost in congestion, but the WA23 handles it aplomb.



What about Classical? One of my favorite albums lately has been “Tchaikovsky & Schulhoff: Orchestral Works” performed by the Pittsburg Symphony Orchestra & Manfred Honeck. Violins, violas, cellos, and double basses have real sonority. Yes, the strings sound wonderful, but the brass and horns really take the cake for me on this one. Trumpets can typically sound blaring to me, but with the WA23, there is trumpet prominence with no biting forwardness. The brass instruments all sound rich and pleasing, as do the woodwinds. The timpani and drums once again also have a good sense of tone, impact, and bounce to them. It is a really, really good listen.

While there are great instances to show off the treble response in the tracks that I have outlined already, one track that I want to mention specifically that brought a smile to my face was Janet Jackson’s “Together Again,“ from her album The Velvet Rope. The beginning 50 seconds feature a heavenly harp that glissandos a few times, panning across the sound stage. There are also some distant chimes that sound ethereal and angelic. Janet begins singing and the whole sequence just has this beautifully airy quality to it.

I have also listened to a good amount of hard rock and metal from various bands, like Metallica, Dream Theater, Korn, System of a Down, Avenged Sevenfold (their track “Nobody” was a real enjoyment on this amp), which can be intense and have a lot of bite and grit. For longer listening periods that normally would be fatiguing, I did not experience that with the WA23, in fact, I found myself more engaged as I was listening. A few things contribute to that— one: the drum kits, specifically the crash and hi-hats can be a bit much for extended periods of times but aren’t as edgy here. Two: guitars, both acoustic and electric, really have a more musical quality on this amp. Three: Drums have more tactility and punch on this amp and just simply sound better.



I truly cannot decide what aspect of the WA23‘s sound signature that I like more, it is all just so good. I have listened to hundreds of tracks and on countless albums, sometimes multiple times. Many times coming to the end of a track or album, and I think I’ve nailed down a favorite aspect, then I move onto another set of tracks or a different genre, I change my mind. I’ve written examples of elements of how it sounds and if you couldn’t tell, I am utterly enamored by it. Bass digs deep, its impactful, its textured, its full-bodied and lacking bloated, its realistic. Midrange range is rich, lush, and engaging, without being too thick and soupy. Treble is sparkly, immensely detailed, and free of harshness, all while retaining a very sweet quality to it. Let me be clear, though, I use words like lush and rich, but this amp is not dark. It does not sound muffled, rounded, or closed in at all. Transient response is superbly fast. Sound stage ranges from massive, when the song calls for it, to intimate when it needs to be. Holography is supreme with a remarkable level of depth and precision in layering within the sound stage.

I have a difficult time finding fault in the WA23 Luna. It’s not a perfect amplifier, as I mentioned earlier, but it doesn’t really do anything wrong outright. Other amplifiers outclass it in individual sound elements, but it’s not going to be huge margins there. The WA23 is just so well-rounded. I’m reaching when finding anything remotely negative to say about it. If I say, it runs hot or that it’s quite heavy, does that count? Well it does and it is, but that ought to be expected. Oh, I could mention as a negative, this could not be used with any of my IEMs. My 64Audio A12t and Thieaudio Monarch Mk III both had a pretty noisy, buzzing background plugged into it. I suppose, the aesthetics, while incredibly unique, will not be for everyone, either. There is no faraday cage to protect the tubes, if you are worried about that. Also, yes, this could be a deal-breaker to some, but the WA23 is a single-ended design and that may not appeal to everyone, though even with that, for convenience, there are XLR inputs and outputs that can be used.

There aren’t many pieces of equipment that have me giddy in anticipation to use, but the WA23 has me eager to press the understated golden power toggle. I simply get lost in the music with this amp; hours will go by while I listen. It’s been over six weeks since the WA23 arrived and not a day has gone by, whilst home, that I’ve not listened to this amp. It’s superbly nuanced yet grandiose in its dynamism, harkening back to what I stated at the beginning regarding the duality of this amp. I also stated that I lean heavily towards solid states, but the WA23 has me questioning all of that. Even with stock tubes, this thing is remarkable. Others might prefer a more clinical or neutral sounding amp, even within the tube realm, the Feliks Envy or Woo WA33 will likely fit the bill for those folks. Others might prefer an amp that will lean even more lush and romantic. Yes, there are other amps I’ve heard that have better individual characteristics, being more detailed or resolving, having a larger soundstage, having more lush, rich quality, or having better macro dynamics, but this amp stays right up there among the very best of each of them, all whilst staying uniquely well-rounded. It does it all, while being more musically engaging.

The Woo Audio WA23 Luna is a statement piece. And it is a work of art.

I was contacted by Burson Audio with an opportunity to sample the V6 Classic OpAmps. I jumped at the opportunity to give the Classics a try and compare them to the V6 Vivid OpAmps that come stock in the Burson Conductor 3X Reference I have been using.

Full disclosure: Burson Audio sent me these samples and in return I have only been asked to provide honest feedback regarding my findings.



I received the OpAmps a few days after first being approached and immediately installed them into the C3XR. For clarification, I’ve only been provided a single pair Classic OpAmps and the C3XR has place for two pair, for a total of four OpAmps. There are a pair of OpAmps for the L/P Stage and a pair of OpAmps for the I/V Stage on the circuit board. I have done listening with the pair of Classics in both stages, the L/P and the I/V. In my multiple listening sessions I swapped between the two stages to see what differences I was able to experience. I did find a little bit difference, which I will touch on in a little bit.



First, comparing the V6 Classics versus the standard V6 Vivids, I first tried the V6 Classics in the L/P stage and my initial reaction was there was a bit more sweetness to the sound. Acoustic guitar strums sound a little bit lively and tangible. There was a little bit more energy and coloration making it appear more palpable. Vocals also have a little bit more richness and body. Both male and female vocalists just had a little bit more lushness to their timbre. Sound stage on the Classics seem to have shrunk a bit though; the sound it produces is just a little bit more intimate. Instrument and detail separation within the sound stage appear to have less physical space between them. Vocals are more forward in presentation and they sound a little more in my head instead of out in front of me.



There appears to be less airiness to the sound. The trebles seem slightly more tapered and don’t quite have the same sparkle but there is still a beautiful richness that extends into the trebles. There may be slightly less energy in the treble range than on the Vivids, which make the Classics a little less revealing in nature. It probably is better described as a little bit less analytical in its sonic approach. Voices have a little bit less of a breathy quality to them, adding to that vocal lushness I had mentioned. Midrange overall sounds fuller and creates a little bit more of a warm sound. With both the reduction of the treble and the fuller bodied mids it provides a bit more of a relaxed, kick-back and listen approach.

Bass response seem just a touch weightier as well. The sound has just a bit more impact in the mid-bass region, but that impact doesn’t seem to extend to the lowest frequencies. There’s not less sub-bass compared to the Vivids, rather the mid-bass sounds slightly elevated. Kick drums have a stronger presence than on the Vivids.



While the Classics seem to have an “easier listening experience” feel to them, with warmth and richness, it comes at the expense of the speed in the sound. Articulation definitely is not as fast as the Vivids; however, this is not to the point of sounding smeared together. Transients throughout the frequency range seem just a little bit more rounded and smoother sounding. Attacks while they seem weightier don’t have as quick of an attack or onset and take ever so slightly longer to decay from.



Swapping the pair of Classic OpAmps in the I/V Stage and having Vivid OpAmps in the L/P Stage position, I would say mostly things are more similar than different to my findings stated above, however there were a couple things that I did note as sounding different. The first thing I had written in my notes was a little bit more weight and presence in the bass. The sound stage size felt about the same size in width and depth, but I did note that the sound seems a touch more ambiguous. What that means, delineation within the sound stage seemed a little bit blurrier. Main vocals sounded a little broader and less centralized, as if it was filling a little bit more of my headspace. Detail retrieval and articulation seemed about the same with the Classics in the I/V Stage versus the L/P Stage.



While I’ve taken time to pinpoint the differences that I experienced between the stock Vivid OpAmps from the C3XR and the Classic OpAmps that Burson graciously sent over to me, I will be candid and say that the differences are not as monumental as, say, changing amplifiers entirely. These OpAmps provide subtle changes that don’t drastically alter the original characteristic of the amps they are installed in. That being said, as I’ve aged my listening experience and what I look for in my sound characteristics has shifted. I used to truly value lushness and that relaxed, laid-back listening experience, which would have put the V6 Classic OpAmps right in my wheelhouse. Nowadays it seems that sound stage, precision, articulation, neutrality outweigh my earlier preferences in sound. That said, there’s no real wrong way to listen and I think Burson in their expertise knew that when making and offering both the Vivid OpAmps and the Classic OpAmps. Each have their strengths and their weaknesses, but having flexibility to OpAmp roll make trying to figure out just what suits your listening preference an easy and relatively inexpensive option. So while, I will likely stick to the Vivids for my listen experience, I certainly will whole-heartedly recommend you try the Classic OpAmps to see what it can do for your listening experience.

For referential purposes the equipment that I used was my iMac with Tidal fed via USB to the Burson Conductory 3X Reference. For headphones, I used both the Hifiman Arya and Hifiman Susvara. And here’s a list the songs that I listened to throughout my listening session:

Apocalyptica
Inquisition Symphony - One
Chanticleer
Sound in Spirit - Como Pod’ a groriosa, Night Spirit Song
Hans Zimmer
Batman Begins - Molossus
Dune - Dream Of Arrakis, Herald of the Change
Inception - Dreams Are Collapsing, Time
Interstellar – Mountains, No Time for Caution
Tool
10,000 Days – Jambi, 10,000 Days, The Pot
Michael Buble
Call Me Irresponsible - The Best Is Yet to Come, It Had Better Be Tonight, Everything
Ludwig Goransson
Tenet – Priya, 747, Sator, Trucks In Place, Inversion, Algorithm
Imogen Heap
Speak For Yourself - Hide and Seek, Have You Got It in You?
Frou Frou
Details - Let Go, Maddening Shroud, Shh, The Dumbing Down of Love
Will Smith
Big Willie Style - Gettin’ Jiggy Wit It, Just The Two of Us
Mormon Tabernacle Choir
Sound of Glory - Battle Hymn of the Republic
Voctave
Corner of Broadway and Main Street Vol 1 & 2 - Disney Love Medley, Bring Him Home, You Will Be Found, Remember Me, Prince of Egypt Medley
Metallica
Symphony & Metallica - Enter Sandman, One, No Leaf Clover, Master of Puppets
Billie Eilish
When We All Fall Asleep, Where Do We Go? - Bad Guy, Bury a Friend, ilomilo
Nora Jones
Come Away With Me - Come Away With Me, Nightingale , Don’t Know Why, The Nearness of You
Jack Johnson
In Between Dreams - Better Together, Sitting, Waiting, Wishing, Crying Shame
Lorde
The Love Club - Royals