Plussound Sonora

I love to sniff graphs. I browse squig.link and head fi for new and exciting graphs just to see if there’s something I want to purchase. One day I hope I’ll find a sleeper hit like the Audiosense DT200, which was 5 years ahead of it’s time, or the 64audio N8 which is far and away the best CIEM I have owned. On a typical day, I would have sniffed the Plussound Sonora graph and gave it a hard pass. The bass looks bloated and the treble looks absolutely terrifying but, having the opportunity to test, it has taught me a lot about what tasteful coloration means and more importantly what coloration of neutral I like.




All of my listening has been done using CD rips and Tidal played through Roon. This unit was supplied to me through a tour being run by Sebastian. Thank you for including me. All thoughts in this review are my own and I was not compensated for any part of this.

First and foremost, I think I would be remiss to not mention an absolute deal breaker for me with the Sonora. This is the worst fitting IEM I have ever tried. That is unfortunately not hyperbole. The angels protrude into my ear at the worst spots. The shape prevents it from fully entering into the concha, leaving my canal to bear the weight of this absolute behemoth. The shell itself is textured oddly making it “itchy.” If I move around too much it starts to rub, irritating my skin. I have never had issues fitting large IEMs before. Elysian Annihilator 2023, STORM, Canpur 622b, Multiverse Mentor and the newly hyped Moses are all totally acceptable, but this thing, it scares me.



If you’re still reading this, that means I haven’t scared you away! So let's talk about the sound. I would call the Sonora a bright W shape. The coloration is tastefully done, but this is not neutral in any form. The treble is boosted, the vocals are boosted and the bass is boosted. It reminds me a lot of polarized sunglasses or impressionist paintings. They look like what they’re supposed to look like, but have an artistic flare that is immediately not “normal.”

One of my first and most immediate let downs was the bass. This was the first moment the graph failed me. I had expected something lush and warm, but the overall balancing of the air and the bass seems to be in favor of the air. The low end thump isn’t the most slammy and dynamic and the mid bass / lower mids is lacking a bit of that texture that I expect from any IEM at this price point. My test for subbass is “How you Like that” by BLACKPiNK and “Neon Medusa” by the Midnight. I was able to get more slam from my N8 and STORM while I remember significantly more texture from my Annihilator. Honestly, I get more slam from my Dunu Mirai which is a significantly cheaper entry into hifi.

The Sonora is a 2DD+4BA+2EST setup, and while I don’t really buy into driver memes, I would say I typically have found most 2DD woofer setups lacking. The decay feels almost like old school BAs, lacking impact and texture. When I was testing my more typical library for bass texture, I was similarly disappointed. The bass from Snarky Puppy, Dave Matthews Band, and the Grateful Dead was lacking in what I typically expect from a TOTL set at this price. 5/10

I actually love the mids on this set. They aren’t natural and they aren’t normal sounding, but I love them. Bluegrass string plucking is aggressive and textured, piano strokes are forward and exciting and vocals are lush and inviting. The more I listen, the more I am hesitant to take them off. Every song gets me further and further into that musical bliss that I really don’t feel that often anymore.



My test tracks for mids are “Turmoil and Tinfoil” by Billy Strings “What Would you Say” by Dave Matthews Band “Shofunken” by Snarky Puppy and “bye” by Ariana Grande. Each of these songs represents my broader library and help me evaluate if an IEM is more of a specialist or generalist. I thought this would be an IEM that would be a bass cannon, reserved only for those that love EDM, electronic music or just way too much bass. I actually think the mids are what make this IEM special. I had started testing it with retrowave and was disappointed, but switched it to my more typical listening and I was blown away. BIlly’s flatpicking, Dave’s cowboy strumming and David Grisman’s mandolin shredding are just TOTL worthy to my ears. 8/10

Treble from track to track was up and down. The big issue with this IEM overall is the amount of air above 7500hz. This creates a sense of intense splashiness on my old poorly mixed jazz records or the pop/rock records that I also love. I use Dave Matthews Band as a typical test of treble. Their mix typically pushes Carter’s playing to the front and he relies heavily upon high treble percussion like chimes, bells and such. Between DMB and my old hank Mobley records, I found the treble to be a bit too splashy, but not totally egregious. I think the Sonora is a flavor that people might like, but I think the amount of upper treble is just a bit too much for me. 5/10

My theory about the treble and bass response is that the bass is so boosted and the treble is so boosted that they actually balance each other modestly. The amount of air really prevents this IEM from slamming because the treble is so distracting. The bass is so thick that it holds the overbearing treble back and controls it just a hair. I think Plussound created a balancing act that has surprised me. On paper, this is an IEM that I should hate, but yet find myself really gravitating towards.

I think one of the reasons I like it so much is due to the stage that it creates. The stage width is quite large for an IEM. On “What would you Say” Stefan is placed in front of me, while Dave is to the left and Leroi is to the right. John Popper flies in with the harmonica and it gives me chills. On Donny Hathaway’s “I believe it to my soul” the horns are solidly on my left and the bass guitar is clear and centered. The vocals are lush and not too forward. The stage width helps really enhance the separation of each instrument ensuring that every piece of the mix is clearly defined and distinguishable. I would say that Plussound really nailed the subjective qualities in terms of staging and definition. 8.5/10


My heart wants to recommend this Sonora, but my brain is telling me it’s not a good idea. If you like treble, and are ok with terrible fitting IEMs, I would say Sonora should absolutely be a consideration. If you have tiny ears, or love to graph sniff, I would steer clear. On paper, this IEM shouldn’t work. It should be bright and bloated with no mids, but to my ears I don’t hear that. I get a wonderfully colored sound that really helps my library shine. However, the treble is still very aggressive and the bass is just ok for an IEM at this price point. I would probably say that someone that likes this IEM would like the Annihilator 23 more for sound and get an improved fit to boot. At lower budgets, I think I would rather take the Dunu Mirai or 64 Audio Nio over this for better bass dynamics and top quality fit.

The mids on the Sonora are addictive to me, but I think some of the other faults are a bit too glaring to be a true recommendation at $3500. I will give it a 3.5 out of 5, but I would probably give it a 4.5 if the fit was more normal. Feel free to drop any questions if you have any!

thaslaya's star rating system:
☆☆☆☆☆ - Fantastic!
☆☆☆☆ - Recommended
☆☆☆ - There are buyers but not for me
☆☆ - Can't see the appeal
☆ - Product is a failure

Disclaimer:
This product was provided by Plussound for a tour through Head-fi. I recieve no compensation and all thoughts and opinions are my own. A special thanks to Plussound and Sebastian Chiu for organizing the tour!

Non-affiliate link for those interested:
https://www.plussoundaudio.com/earphones/sonora.html

Gear used:
●Samsung Galaxy s25 Ultra
●HiBy R3 II
●Various DAC/amps

Source:
●Listening was done using Amazon Music HD/Ultra HD and local FLAC files.

Introduction:
Plussound, based in Los Angeles, California, was founded in back in 2012. Many may think of them as just a cable manufacturer, but they released their first IEM, the Allegro, in 2023. They have recently released two additional high-end models, the Sonora and Volta. Both have tribrid driver configurations; the Sonora features two dynamic, four balanced armature, and two electrostatic drivers. The Volta has a similar configuration, but with two fewer balanced armature drivers. These high-end models also have high-end price tags to match: the Sonora is available for $2999 and the Volta for $2499. Let's break down and compare these two latest TOTL models from Plussound and see how they perform.

Build, fit, ergonomics:
Both the Sonora and Volta come in nearly identical packaging with nearly identical accessories. The boxes are small but quite heavy due to everything included inside. Upon opening the box, you are greeted by a very nice leather case with a plastic piece on top that says "Designed and hand-assembled in Los Angeles, CA, USA". Inside the case is an organizer that displays both the IEMs and the cable. The build quality of the shells is very nice. They are made of anodized aluminum alloy, and both sets have identical dimensions. The shells are a bit on the larger side, but they feel very solidly built and, due to the aluminum, are not that heavy. The shape and design are somewhat industrial but with a sleek finish, and the texture is a nice addition. The aesthetics are the only thing that varies, but even then, only very slightly. If the colors weren't so starkly different, you might think the faceplates have the exact same design, but they are subtly different. The Sonora have a gold and maroon colorway that reminds me a lot of Iron Man, and the Volta are gray/silver, which makes me think more of War Machine. Although the shape is a bit different, the fit is very comfortable. The insertion depth is about average, and the nozzles measure 6.2 mm at the widest point, where there is a lip to help hold tips. Both models utilize a very slightly recessed 2-pin connection, and there is a long vent located nearby that helps alleviate any pressure. The included cable is the PlusSound Copper XL cable, which retails separately for $750. This pure copper cable is chunky but has excellent ergonomics and a nice weight balance. The Y-split also has a pop of color that matches the shells of each model, which is a great touch. I would expect nothing less than a stellar inclusion from PlusSound, as they are a cable manufacturer first and foremost. However, my only minor nitpick is that the cable's color is not a great match for the Sonora. I would also like to see an option to purchase the IEMs at a discounted price without such an expensive cable inclusion. I think more companies should offer this option for audiophiles with an already extensive cable collection. There are nine total pairs of tips, including three silicone, three Comply foam, and three silicone foam hybrid tips. I tried the stock tips but ultimately preferred the JVC Spiral Dot tips. The case is excellent and comes in matching colors to each model. It is made of soft leather, and the IEM holder can be removed to allow for more storage space. It is not a very pocketable case, but it does feel like a premium inclusion. The rest of the accessory package includes a cable tie, cleaning cloth, cleaning tool, small black leather bag for the shells, larger black leather bag, metal warranty card, and metal tip holder. Overall, the accessories are fantastic and absolutely what I would hope to see at this price point.

Sound impressions:
The Sonora has an energetic, V-shaped overall tuning with an elevated bass shelf, a decently accentuated upper midrange, and a bright, airy treble. The note weight is just above average and strikes a good balance, allowing bass notes to sound full without weighing down the treble. The Sonora is not necessarily hard to drive and can reach loud volumes from a simple dongle, but ESTs generally benefit from extra power, and this one is no exception. The detail retrieval is very strong and definitely one of the better aspects of its technical performance. I never fear missing any nuances or subtleties in tracks, but I also don't feel like details are being forced upon me. The soundstage is full and spherical, with a generous sense of width and depth. The timbre does have a slight sheen at times that I associate with EST drivers. It's not the worst by any means, but it's also not the most natural-sounding at times. The imaging is strong, with a great sense of accuracy and precision, but perhaps slightly better left-to-right than with distance. The Sonora's dynamics are great, and the fun tuning holds up very well regardless of volume level. The layering is also well done, and even though the notes are well separated, it still retains a sense of coherency that is quite impressive. Overall, the Sonora is very strong in just about every technical category, and I feel that it performs up to the standard for a TOTL experience.

The Sonora and Volta can be quite source-sensitive, so I recommend trying as many pairings as possible to find a synergy that suits your preferences. As I am quite treble-sensitive, I found that the Sonora pairs great with the Muse Hifi M5 Ultra tube amp. It helps to add some warmth without sacrificing detail. The HiBy R3 II is also a great choice for a more controlled top end. The DUNU DTC480 is a solid choice to preserve the overall energetic tuning but with a little less treble peakiness.

●Lows - The Sonora has a good balance of mid and sub-bass, but I would welcome more bass quantity overall to help offset the treble. I would like to see the sub-bass further extended and the mid-bass lacks a little impact and oomph for me. The texture is very clean, and the resolution is solid, though not the absolute best I've heard. The rumble and reverberation are great, but I think the decay is just a hair too quick and would prefer it to be slower. The bass is agile, with double kick drums easily discerned, and it never has trouble with complicated bass lines. There is a slight bleed into the midrange, though it's not too detracting. Overall, the Sonora's bass performs well, and while it's not the bass-forward style of tuning that I like, I do find it quite enjoyable. Personally, I'd welcome more quantity, but the quality is very good.

●Mids - Due to the V-shaped tuning, the Sonora's midrange has a scooped lower half and a slightly emphasized pinna gain. Vocals are somewhat forward and accentuated; however, female vocals are able to shine through more, while males are a bit recessed in comparison. Instruments in the lower midrange, like cello and lower brass, do lack a bit of weight and presence for my taste. The vocal and instrument timbre is quite natural and organic, but there can be that occasional sheen I mentioned earlier. Overall, the Sonora's midrange is not quite my style. I would like to see the upper midrange a bit more accentuated to really let the vocals come through. I'd also welcome a more musical and emotive presentation, which I feel the Sonora lacks. That being said, those who prioritize balance, clarity, and detail are likely be very satisfied.

●Highs - The treble is a little energetic and has a brighter tilt with a decent amount of sparkle, air, and extension. Unfortunately, it can come across a bit dry and nearly sterile for me. By that, I mean it lacks musicality and is inherently more detail-oriented, which some may prefer. It's almost like perusing a dictionary: full of detail but not the most interesting read. When paired with a brighter source, the Sonora's top end can exhibit quite a bit of sibilance and fatigue. It's much more tolerable for me when paired with a warm or analog-style source. Cymbals and hi-hats can still sound somewhat splashy to my ear, but snares and claps retain their crispness and bite, though they are less piercing. While the Sonora's treble is not to my particular taste, that's not to say that it cannot still be enjoyable with certain tracks and genres. While it does get fatiguing fairly quickly for me, the amount of detail and clarity here is impressive.

Comparison: Unfortunately, there's no graphs for these two uploaded to Squiglink at this time.

● Plussound Volta ($2500) - As stated earlier, the unboxing, accessories, and build quality are basically the same between the two, so there is no need to compare them here. The only real differences are the driver configuration (the Sonora has two additional BAs) and color. I personally prefer the milder gray/silver aesthetic of the Volta, but I am sure some will fall for the red and gold Sonora. When it comes to tuning, the Sonora is easily the bassier of the two, with an upper midrange accentuation and more brightness in the treble. The Volta is much more balanced in comparison, with less bass emphasis and pinna gain, but still with a decently accentuated treble. In the bass, the Sonora has a fuller low end with better extension, more rumble, and more mid-bass, whereas the Volta has a bit more forceful punch and attack, and a generally cleaner-sounding bass. As for the midrange, the Sonora has more forward and accentuated female vocals, but male vocals are a bit recessed in comparison. The Volta, however, is smoother and more even-keeled in the entire midrange, and vocals exhibit more emotion, if not as forward-presenting as on the Sonora. The Volta also has a bit more lower-midrange emphasis for classical and orchestral arrangements. The treble is where these two diverge most, and where the starkest contrast lies. The Sonora is inherently brighter, with much more energy, sparkle, and air. But it also has some sibilance, especially with breathy vocals, cymbals, and hi-hats in particular. The Volta still has a certain crispness and a slightly bright-leaning treble, but it is less incisive and ethereal in its presentation. As expected, these two are pretty even in terms of technical performance, but the Sonora definitely wins in dynamics, while the Volta has a more natural timbre to my ear. In summation, both sets have their strengths and offer different sound signatures, but ultimately my tuning preference leans more toward the Volta. It has a somewhat laid-back and easy-listening style, especially when paired with tubes, which is much more enjoyable to me than the Sonora's energetic and fatiguing treble response.
My pick: Volta

In conclusion:
For only their second and third IEM releases ever, Plussound came out swinging with a one-two combination in the Sonora and Volta. Both models sport impressive build quality, a fantastic accessory package, comfortable fit, and unique aesthetics and tuning. The Volta synergizes well with singer-songwriter, classical, and orchestral music, or simply for a more relaxed listening session due to its better overall balance. For more upbeat genres like pop, rock, and R&B, or a more exciting presentation, the Sonora really brings the energy and fun. The source also plays a big role. The Sonora, being the brighter of the two, definitely has some treble notes that are a bit bothersome for me. However, when paired with a warmer source, like tubes, that treble energy is reigned in enough for me to better enjoy the fun-natured tuning. If I were forced to pick only one, I'd say the Volta edges out the Sonora, mostly due to its more emotive vocal presentation. I would definitely recommend demoing both if possible before making a blind purchase, since they excel with different genres. I also discovered that both the Sonora and Volta benefit from the use of an impedance adapter and take well to EQ for those who want to customize the tuning further. Plussound might be known as a cable company first and foremost, but they sure know how to make really solid IEMs as well. Unfortunately, the high cost will be a barrier for many. I'd really like to see what the company could do with a more budget-friendly mid-fi release in the future.