FiR Audio M5

General Information

The M5 TOTL by FiR Audio, a new market entrant manufacturing tubeless universal and custom IEMs

Latest reviews

Pros: Good balance between the bass, mids and highs. Treble isn't too present, even though it's produced mainly by an EST. Comfort and look
Cons: Price, bass (not the most impressive for a DD)
I had the chance to demo this IEM for about 2 weeks by participating in a loan tour, organized by a member of the community. I would like to thank him for the opportunity !

As a disclaimer, the sources used with the FiR Audio M5 are the iFi Micro Black Label and Sony NW-WM1A. I found the M5 to be fairly resistant to hissing, which makes it quite versatile with sources (big bonus if you're not sure your DAP or DAC/AMP is quiet enough). I also found the comfort to be quite good for long periods, as I did not get any pressure build up whatsoever. Stock cable is quite good. It is pliable, but not the softest. Feels good on the ears, it doesn’t itch or anything.

The music I listen to tends to be quite vast, but it mostly revolves around metal, rock, instrumental and soundtracks. Here is a non-exhaustive list of the bands I used to gather my thoughts : Dream Theater, Haken, Jinjer, Opeth, Tool, Gojira, Killswitch Engage, Lamb of God, Breaking Benjamin, Chevelle, Soen, Karnivool, Andy Timmons, Marco Sfoli, Anup Sastry, Intervals, Plini, Animals as Leaders, Hans Zimmer and Ramin Djawadi.

As for as sound goes, I think this particular IEM goes for an exciting sound signature, with decent bass (not the best, even though it’s a DD, but gets the job done). The sub bass extension and mid bass are about average for a DD (still better than most full BA setups).

Treble does not feel exaggerated, even though most EST implementations tend to have a bit too much energy for my tastes. Can definitely be a little hot for some people, but I did not hear unbearable peaks.

Mid range is quite good ! Definitely goes for something balanced. Vocals and instruments are not emphasized, they just sit a little back compared to the rest of the mix. Detail pickup was above average for a flagship. It could not keep up with some of the other models I’ve tried (namely, the Anole VX and U12t, which are both cheaper). Still decent overall, but not amazing considering the price.

All in all, I'm not sure I would recommend this IEM at full retail. The price is higher due to the technologies used (trybrid with EST, DD and BA drivers), but the actual sound does not feel improved per se. The price would be fair at around 1.7-1.9k usd, so I consider MSRP to be quite overpriced. Would probably look at alternatives from 64audio instead, although the bass response probably won’t be as good. The techs used are similar (LID, APEX, etc.), so you can something comparable if that’s something you care about.
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Pros: Beautiful, natural-sounding tonality*
Good treble extension
Nice cables
Cons: Very expensive
Mediocre isolation
Channel matching might not be perfect
High unit variance
Fairly high levels of 3rd-harmonic distortion
Very low/variable impedance above 200 Hz
Not particularly ergonomic
Proprietary connectors
Ouch, that's a lot of cons. Why would I give 4.5 stars to a headphone with so many negatives? Well, because the M5 can sound absolutely fantastic. I've tried one pair of M5s that were possibly the most enjoyable in-ear monitors I've ever heard. To my ears they sounded extremely natural, with good extension at both ends - not overpowering, but just enough of a lift at the extremes that they never sounded boring.

If you purchase the universal model in the US, you can also customise your own cable on the FiR Audio website, which is pretty cool. I'd recommend memory wire in the ear hooks because of possible fit issues (more on that later). The stock cables are soft, flexible, have very low microphonics and seem to be high quality.

Some more thoughts on those cons...

Price: If there's a company out there who feels their R&D talents justify a massive hourly rate, I guess they're free to set a commensurate price for their headphones and the market will decide. But the parts that go into these headphones wouldn't seem to justify a nearly $3000 sticker price. I guess we should just be patient though... in 10 years time when there are $50,000 IEMs on the market, $2800 will look like a ChiFi bargain.

Isolation: The M5 is vented, so it doesn't offer much passive noise isolation. If sound isolation is your highest priority, you'd still be better off with an Etymotic.

Channel Matching: It was reasonable - not 100% perfect on the first demo pair I first tried - but reasonable. Note, all M5 measurements here were made on a standard 711 coupler with Cp100 SpinFIt eartips. These graphs are all uncompensated:

Despite the small channel imbalance, these still sounded wonderful. After I made the mistake of pointing out the channel imbalance on this particular demo pair, Bogdan (FiR Audio owner/CEO) re-tuned them. The result was then near-perfect channel matching, but a disastrously-different FR, with a much heavier mid-bass, and a dull, muddy and pretty lifeless sound. So I guess the moral of this story is be careful what you wish for? ¯\_(ツ)_/¯

High unit variance: I expect subjective impressions of the M5 will have big variations. By which I mean even more variation than is normal for headfi. This is because of a couple of possibly not-so-good points, namely, low impedance and very noticeable variations in production units. As a result, subjective opinions might not be all that helpful here. Showing a frequency-response graph gets a bit tricky too because I've heard three models that all sounded quite different:

Are you ready to roll the dice?!

One positive point worth mentioning here though. In certain IEMs, foam tips can massively damp the treble. Because the M5's bores are fairly wide, I didn't notice that much difference between silicone and foam eartips:

The M5 comes with its own proprietary brand of foam eartip. It looks like Comply, but apparently it isn't.

For whatever reason, big-name-brand companies seem to do better with QC in terms of tight manufacturing tolerances. Unit variance is possibly the Achilles' heel of the M5. From model to model, its FR appears to be all over the map. @crinacle also has several measurements for the M5 on his website and none of them match either. (Note @crinacle also shows a sizable FR spread for the other FiR Audio IEM models.) Bogdan suggested couplers and eartips might be responsible for the variations in measurements, but I don't entirely agree. I have a fairly careful procedure and all my measurements were made with the same eartips, same insertion depth, same coupler, same mic, and are 100% repeatable. From what I've seen of @crinacle's work, his measurements also seem to be carefully done and are usually pretty consistent with mine. (My measurements were made on a GRAS RA0045/40AO coupler/mic, but I also have the same coupler that @crinacle has, and measurements from my various 711 couplers match very closely for FR.) These unit variations with the M5 are real and easily audible.

Fairly high levels of 3rd harmonic distortion: At 80 dB, it's ok. Typical of what I usually see in other balanced-armature IEMs:

At 94 dB, the third-order harmonic distortion got so high in the mid-range that my measuring software quit (by default, REW stops if distortion exceeds 1%):

Does this matter? Probably not. This isn't random noise or intermodulation distortion, but harmonic distortion - in other words, harmonics that could/would exist in nature. In theory, this could change the timbre of a sine wave, but in actual music the dominant factor is the underlying frequency response, given that the harmonics of the instrument(s) are already present in the recording and the perceived FR of the headphone is almost certainly going to be deviating from flat by way more than that THD percentage anyway. Consider the irony of chasing a 0.0001% THD and then plugging those same headphones into a tube amp :)

Impulse Response: The M5's impulse response is fairly typical of balanced-armature headphones - rise/fall time is not as fast as electrostats like the KSE1500, but settle time is faster. It's also faster than a dynamic driver like the Xelento, and much faster than the planar driver in the RHA CL2:




Does any of this matter? Possibly not. Although it's intrinsically interesting, I haven't seen much evidence to suggest that we have an urgent need to be able to resolve impulses <50 microseconds apart in real music.

Square-Wave Response:

Ok, this doesn't look much like a square wave, but again I'm not convinced this has much bearing on real music.

Very Low (and Variable) Impedance: The quoted specs say 6.8 Ohm, but this is the impedance I measured, which was pretty consistent on both channels of two different sets of M5s:

The impedance is 6.8 Ohm only once you get below 100 Hz. It's way lower than that at frequencies above this, and drops below 2 Ohm in the mid-range. I've never seen a headphone with an impedance this low. Together with its variation with frequency, this definitely could have an audible effect. How many people have source devices with an output impedance lower than 0.25 Ohm? My guess is not many. I've seen mention of LID (linear impedance device?) in some other M5 reviews, but can find no mention of this on FiR Audio's website. If the M5 does have some magical device to prevent shifts in FR with varying output impedance, it doesn't seem to be working very well. Here are measurements of the exact same headphone (without shifting anything in the coupler) being driven by an RME Babyface Pro FS and an A&K Sp2000 which have output impedances of 0.1 Ohm and 1.0 Ohm, respectively:

Both these output impedances are already pretty low, but there's still more than a 2 dB shift in the mid-range. It seems safe to expect the FR to shift noticeably when moving to/from devices with larger (>=1 Ohm) output impedances.

Sensitivity: I couldn't find any official specs listed for this, but I measured it as approximately 110 dB/mW @ 1 kHz. That should mean that the M5 is unlikely to exhibit any noticeable hiss. And even if it does, that wouldn't be the fault of the M5 and you really ought to get yourself an amp with a lower noise floor :wink:

Ergonomics: If you squeeze lots of drivers into one IEM shell, you're probably not going to get something as nice and tiny as a Xelento. But why not at least make them ear-shaped and angle the nozzle up into the ear canals properly?
The fit of the M5 is ok. It's not the horrible torture that is the Campfire Audio Andromeda, but it could have been so much better - at least for my ears. I need to rotate the M5 back a bit farther and angle them out in order to get a good seal, and as a result, I've had to use a couple of funky bends in the ear-hook memory wire in order to get the cable to stay behind my ears, as the natural tendency, given the fit of the IEM, is for the wire to end up hanging next to, but not behind, my ears. If any of that makes sense?

Proprietary Connectors: The M5 comes with a pretty decent stock cable which you probably won't want to change - which is just as well, because you won't easily be able to. The M5 uses FiR Audio's own proprietary RCX connectors. I understand not everybody likes MMCX connectors, but, on the other hand, a proprietary connector makes it difficult/impossible to ever switch out the stock cable. I like the M5's connectors, but I can't see these catching on as a new universal standard anytime soon. And in the meantime, none of my existing cables are interchangeable with those on the M5. If you're handy with a soldering iron, FiR Audio sell their RCX connectors for $30 a pair; if not, you're probably not going to be doing much cable rolling.

The KSE1500 are still the most resolving headphones I've heard. However, they require a separate electrostatic amp, and I actually found the model #1 M5 to have a slightly more natural-sounding tonality. (It's a long, sad story, but model #1 got destroyed by FiR Audio and is now in that special place in the sky where all good headphones go when they die.) I suspect the only really significant metric in the KSE1500 is its tuning, but it does seem that it's difficult for other types of driver to match the treble extension of the Shure electrostats, so the M5 does a respectable job here:
The Xelentos continue to be one of my all-time favorite headphones. They're not 100% perfect though as their mid-bass is a little heavy and they have less air up-top than the FiR M5:

Does this make the M5 a more enjoyable listen? I thought the M5 model #1 was right up there with, and even slightly surpassing, the Xelentos. Model #2 - not so much. And model #3 was a disaster. Yet again, everything boils down to the tuning. Xelentos have a warmer, richer tonality, while the M5, generally, sounds more neutral or reference-like. The M5 has a tiny bit wider soundstage, but we're talking centimeters at most.

Xelentos are one third of the M5's price, much smaller, with much better ergonomics and standard mmcx connectors. One word of warning though - there's now a plague of very authentic-looking, but poor-sounding, counterfeit Xelentos all over the internet. I would consider it risky buying Xelentos these days from anywhere other than Beyerdynamic.
The new kid on the single DD IEM block is Final Audio's A8000 - a single Beryllium driver in some fairly nice-looking, silvery-polished shells. The A8000 might look a bit large and not very ergonomic in photos, but they're fairly small in real life and have a surprisingly secure fit (even more so than the Xelentos, at least for me). The buds are slightly heavy, but that's not really noticeable once they're in your ears. They fit and seal perfectly in my ears, which, for me, is an extremely rare and pleasant find. Given their appearance, I was surprised at how deep an insertion I was able to get. (<-- Insert obvious Steve Carell/Office joke here.) The one small catch though - the edges of the A8000 are razor sharp. I'm not exaggerating - the A8000 could double as a pocket knife. There's a chance this could bother people wearing them for extended periods, at least if you insert them as deeply and as weirdly as I do.

Here's a comparison of the A8000's frequency response with those of the M5 models I tested:

The A8000 does get remarkably close to the Harman target in the bass and lower mid-range. Note, however, that it's not quite as close to that target curve in the upper mid/lower treble regions:

Jude's measurements (originally shown on his NY CanJam preview video) suggest a closer match to the Harman target throughout the entire frequency range, but note that Jude's measurements were made on a GRAS RA0401 coupler - a coupler that's designed to intentionally damp the half-wave resonance of the ear canal. The RA0401 coupler is an interesting device for design purposes, but not as useful for knowing how IEMs will actually sound in your ear. I've made previous comparisons of the two different types of GRAS coupler, and it's always the same story: the canal resonances are, as intended, pretty much missing from the frequency response: ( Running a frequency sweep, I can clearly hear resonance peaks at ~5.5 kHz and, at only a slightly lower amplitude, at ~8.5 kHz (the fact that I hear the canal resonance at a slightly higher frequency than that indicated by the 711 couplers is probably because of the deep insertion I was able to get with these buds). Try listening for yourself with a frequency sweep. I bet you'll hear that ear canal resonance which the RA0401 coupler suppresses.

What this means to humans with ear canals is that the A8000 might be perceived as a little lively in the lower treble. (Note that the M5, even measured on a standard 711 coupler, does not exhibit any significant narrow-band resonance peaks.) Overall, the A8000 is still a really great headphone - it just leans a bit brighter than the M5. The A8000 uses standard mmcx connectors, and at $2000 (USD), it is cheaper than the M5. My preference could easily change with source material, but if I was forced into one of those awful Sophie's choice scenarios, I'd go for the M5. But honestly, I think most people would be perfectly happy with either.
I realize I'm probably in the minority here, but I don't understand the hype around these. I find their uneven frequency response to result in something that sounds quite unnatural:

They just don't have the realistic timbre and clarity of the M5. They're also pretty large, heavy and not very ergonomic, so fit issues are a serious possibility. I don't think these justify their price. The $250 FLC8d sound better to me than the IER-Z1R.
There's a family connection here between 64 Audio and FiR Audio and I've heard a rumor that the M5 was designed to have a similar tuning to that of the Tia Forte. I'm not sure I see or hear that though. The Tia Forte has a bit of an uneven bump in its mid-range. I don't know if that's the reason its sound never really impressed me, but its 600 Hz bump makes any comparisons with other headphones using normalization around that frequency look rather weird. I definitely preferred the model #1 M5. However, a word of warning... Can you hear the subtle difference between the original Tia Forte and the new Tia Forte Noir? If so, then beware, because that difference is far smaller than the unit variations I've heard in the M5:
The Legend X is my favorite Empire Ears product. They are really bassy headphones, but they're one of the few IEMs that handle the bass properly, i.e., they have more sub-bass than mid-bass. The only reason I don't own the Legend X is because they're large and don't fit my ears well :frowning2:
After many years of ownership, and despite no longer being "new" or a "flagship", these are still going strong and they continue to surprise me with new tricks, e.g., with eartip and filter modifications. Even with the Trishd mod, the SE846's upper treble does roll off a bit earlier than that of the M5, and the M5's dynamic bass driver has a bit more punch. But the SE846 is one third of the price and offers really good passive noise isolation:
A $250 IEM can't possibly compete with the big boys, right? I would disagree. The FLC8d is right up there. It even has tuning options via replaceable filters and it costs less than the price of the FiR Audio M5's cable. Compared to the M5? That's a tough call as I've heard M5 models that sounded much better than the FLC8d and other M5 models that sounded worse:


This is the most difficult part of my review. Can I recommend the M5? I don't know. Most of the negative issues listed here should be relatively minor to most people. The main issues are: 1) whether you can get the M5 to seal and stay in your ears, and 2) if you're lucky with the tuning on the unit you receive.

Unit variance with the M5 can be huge, so even if you've heard a demo pair you like, you're still going to be taking a bit of a gamble on a purchase. Compound this with the uncertainties in tuning any CIEM, and I could never recommend a custom M5. (But then I don't recommend a custom anything.) I'd strongly recommend prospective universal M5 buyers to contact FiR Audio and ask to audition the exact pair they intend to buy. If that's not possible, I'm not sure I could recommend the M5. I've now heard three M5 models: one sounded phenomenal, one sounded good, and one sounded pretty muddy. That kind of loose manufacturing tolerance is not ideal at any price, but it's a poor show at $2800. In fairness to FiR Audio, unit variance of other headphones probably isn't well documented. It's common knowledge that reviewers tend to get A-stock, and actual buyers are often left with somewhat lesser-sounding production units - and in most cases, those buyers probably never ever find out. This might even be the root cause of many disagreements on headfi, where two people think they're discussing the same headphone :wink: If you can demo an M5 with the option to buy the exact unit that you heard and liked, then I would go for it :)
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Awesome write-up. Curious to hear these now
Pros: FULL range sound, deep bass with impact, extended highs without shrillness, dynamic
Cons: I prefer an MMCX connector for cable rolling, some prefer not to have LID, bass can be heavy handed for some

Disclaimer: I am not affiliated with FiR. I received the pair of M5 I listened to as part of the FiR tour.

Introduction: I will apologize, sort of, right now for this review being very similar to those I’ve posted for the FiR M3 and M4. I hope it’s not too boring and repetitive because there is a method to this madness. My theory when I started was to use a similar format for all my FiR reviews in hopes of making it easy for you to perceive the similarities and differences I heard. As you know, I’ve only had IEMs for a few years. Here I am, looking for an upgrade. My current long-term reference for in-ears is the Campfire Audio Lyra II. I like the overall balance of the Lyra II, but enjoyed the bigger bass of the Vega, though I only got to listen to those for one evening. I have been looking for an upgrade ever since discovering I’m an emerging bass-head.

Design: The M5 is a five- way design: dynamic woofer; balanced armature midrange, mid/high and tweeter drivers and an electrostatic super- tweeter. I’ve been intrigued by hybrid designs ever since I bought my Campfire Lyra II. After having the M4 for a bit more than a week, I am curious to find out what the electrostatic driver adds to the sound.
As with the M3 and M4, the M5 housings are generally triangular, and fairly deep. The sound pipes are fairly long. Both of these traits are good for me. Triangular housings seem to fit my ears pretty well and the long sound pipes will let me get deep insertion. I’ve worn ear plugs at work for years, so I am used to jamming things as far in my ear as possible. Shallow insertion feels unstable to me.
The housings are nicely made: smooth with rounded edges. They might be die-cast, but I’ll bet they are milled. I don’t see any fasteners holding the face plate to the housing. The outside looks powder coated: satin black for the body, light gold for the face plates. The M5 have vents below the RCX connector as the M3 and M4 do.
M5 2 small.jpg
The M5 housings are well crafted and understated, like an English luxury car. They are not so sculpted as the Meze Rai Penta I also have (more Italian looking), and cleaner than the Campfire Audio Lyra II. The latest IEM to arrive in my house is the 64Audio Trio. The Trio is slimmer than the M5, and its corners are more rounded.
Meze Penta shells.jpgMeze Audio Rai Penta
Lyra shells.jpgCampfire Audio Lyra II

Packaging: I still can’t make a comment about the “retail” packaging from FiR as I received my set as part of a tour. Truth be told, I don’t much care about packaging anyway. Sure, it’s nice to see a fancy box, but I’d rather have my money put toward the IEMs themselves; or at least good tips. Honestly, after I put the box in the closet, the next time I’ll see it is if I wrap it up to mail it to the new owner.
M5 4 small.jpg
What’s in the box? What came in the box sent to me was a large (for IEMs) metal can with a screw-top lid containing the M5 and a 5-pole (Sony) cable. I’m glad I had some ear phones from a friend who’s a fan of the Sony connection, otherwise I wouldn’t have had an adapter. Would have been my fault, it’s not like FiR failed to disclose which cables were shipping with which tour IEMs. Also in the box was plastic baggie with some extra tips. The metal can is lined with foam, and has a cleaning brush in the lid. But, it’s too big for daily traveling.

RTFM: No literature came with the tour pair of M5. That’s good, I’d have to spend audition time to read it, anyway.

  • IEM Connector: FiR Audio use their RCX connector. I won’t quibble about whether it’s mechanically superior to an MMCX. What I do know is I have a few cables with MMCX connectors I can’t use with these IEMs, and I’ve never worn out an MMCX connector. Perhaps musicians do. I hope FiR will offer MMCX as an option for those of us who aren’t hard on their gear. The cable provided came with “RCX angled black” connectors at the IEM end. I didn’t like them at first: they didn’t fit my ears or with my glasses well. I did get used to them, though. Still, if I were to order a pair of IEMs from FIR, I’d try their “RCX Barrel” connector instead. Perhaps a minimalist strain relief and no memory wire that allows the wire to be wrapped over my ear as closely as possible? I’ve also seen some FiR IEMs provided with RCX and clear over-molding that looked smaller than the black connectors…
M5 3 small.jpg
  • Cable: The FiR cable provided with my tour pair is really thin and flexible. It comprises eight wires, twisted, not braided. Microphonics weren’t a problem for me. No microphone is offered, which is fine by me.
  • Source connector: The tour M5 cable was supplied with a straight 4.4mm penta balanced connector.
  • Tips: I skipped the tips provided with the tour M5. After my experience with the M3 and M4 I skipped right to my Spin Fit 240. I may have tried my RHA dual flange briefly, but the Spin Fits stayed on pretty much constantly.
  • Fit, Comfort, Isolation: I like the shape of FiR’s universal housings. The triangle shaped housings fit my outer ear reliably. I never had any trouble with either M5 ear piece, and the Spin Fit 240 gave me a consistent seal and secured them well. The FiR universal shells don’t nestle into my outer ear like my Rai Pentas, or the qdc Anole VX I had a chance to try briefly (the Anole is shaped similarly to a custom shell, no trouble with fit for me, it was great), but I didn’t have any problems with them either. Choosing between universal and custom would actually be a problem for me. Isolation, with a good seal, is good. I had no problem sealing out the chatter in the group office space I’m currently working in.
M5 5 small.jpg
What I Listened To: I like simple and compact, so I used my AK70 MkII. As far as music, I kept the SD card from my M3 and M4 auditions, so I listened to mostly the same songs. I did add a couple new songs, though.

Soundstage: I am not a sound-staging aficionado, at least not when it comes to head phones. Like the M4, the footsteps at the beginning of Chris Rea’s “Auberge” started way outside my left ear, crossed the stage and stopped outside my right ear. Also, “Sea Wall” from the Blade Runner 2049 soundtrack filled my entire head with sound. Most other recordings I listened to weren’t quite so dramatic. The M5 soundstage generally stayed between the face plates. I had a few new songs on my audition SD card. One is “Adventures in a Perambulator” by John A. Carpenter. Instruments had good separation across the width of the stage and various instruments could be heard left, right, top, bottom and various locations in between. I didn’t notice much layering or depth, but I think that’s me not the IEMs. While I don’t notice much differentiation in height or depth, big orchestral pieces sound similar to what I hear from my normal seat at our concert hall: 20th row center. It could be I am not good with spatial cues. I won’t argue with anyone who tells me I’m full of it here.

Highs: When I received the M5 I dove right in and just let my audition list play. As with the M4, I spent a lot of time comparing the M5 treble of the Trio, since the Trio’s top end is one of my favorite aspects of its sound. I came to this conclusion: the Trio are sweet. By that I mean extended, airy, light, never sibilant, delicate. The M5 I believe to occupy a middle ground between the M4 and Trio. The M5 are not sweet, either, but they have more capability to show finesse than the M4 can. I don’t think the M5 treble is peaky, it doesn’t get fatiguing to me. It certainly isn’t hot or shrill.

“All Right Now” from Doc Powell’s The Doctor is again a good track to compare treble. The cymbals are recorded with intricate detail and no sibilance. The Trio present an amazing amount of detail, shimmer and resonance (that’s not really the right word), while the M4 presented amazing energy and laser-like clarity. M5 has most of the energy of the M4 but lacks a bit of the Trio’s detail. That may sound like a bad thing but I’ll point to Eva Cassidy’s rendition “Blue Skies”. Her voice is front and center, clear and soaring, just like it should be. Right behind her, though, are the cymbals keeping time in bell-like fashion. “Chitlins Con Carne” from Stevie Ray Vaughn’s The Sky is Crying proved its worth again. The cymbals are almost the only treble in the track and easy to focus on. What a treat through both the M5 and Trio.

You’d think New Levels New Devils by Polyphia and “Bandenburg Concerto 1” by J.S. Bach would have only being on my audition list in common. Not so fast. Both allowed the M5’s articulation to shine. In the Bach it was the harpsichord I focused on; in Polyphia’s song “Saucy”: all the weird snaps, stops and starts. Fun stuff when you’re listening to an articulate transducer.

Mids: Every guitar, acoustic or electric, I played through the M5 sounded great. I didn’t listen to any of my Pete Fountain or Don Byron, but clarinets in orchestral settings sounded rich and mellow. Emmylou Harris’ voice on “Deeper Well” was worn and expressive, and Julia Fordham’s voice during “Porcelain” is smooth and clear. While I was enjoying my brief time with the Anole VX I noticed something in Frank Sinatra’s “One For My Baby” (Only the Lonely) I hadn’t noticed before: the first pitch of the first word of nearly every verse is noticeably more baritone than the rest of the verse. It’s almost as if the Chairman’s voice needed to rev-up, make use of some low-end torque. When I listened to the M5 I heard it, not with my Rai Penta. The rest of the M5’s presentation is a treat: Sinatra’s melancholy tenor is smooth and perfectly clean and the piano is behind his left shoulder, I can almost see Joe the Bartender signaling him to play something “easy and sad”.

Back to the smaller scale tunes I listened to with the M3: Miles Davis’ “Half Nelson” (Workin’) was boomy and muddy through the M5. Margo Timmins’ breathy whisper of a voice floats above the deep thrumming bass in “I Don’t Get It” from The Trinity Sessions. I’ve really enjoyed listening to Henry Brant’s Ice Field. Mr. Brant throws everything at the listener, from organ to triangle. I’ve not heard this piece live, unfortunately, but I think I can hear it all. Rosin on the bows of the bassists? Check. Clinky piano right-hand during the jazzy bit near the end? Check. The celli in Bach’s Brandenberg Concerto 1, were at a non-shocking level, in balance with expectations.

OK, back to mids. For dynamics and transients: Keith Jarret’s piano (“Part II C”, The Koln Concert) revealed the M5 lower midrange, as heard in Keith’s left hand, to be full and resonant. I could hear the sound board. I could hear the notes decay as other notes were struck.

In contrast, higher up in the mid-range, the leading edges of the notes played by Keith’s right hand were emphasized. The higher notes of the piano decayed quite quickly, without bloom.

Lows: There are a couple of characteristics about bass response important to me. The first: Pink Floyd must sound good. One of my favorite things about Dark Side of the Moon, Wish You Were Here, The Wall, et cetera is the bass wraps its arms around you and holds you close. It’s warm and smooth and wonderful. The other is: I would love to find a head phone able to reproduce “It’s For You” by Pat Metheny Group (As Falls Wichita, So Falls Wichita Falls) properly. I am beginning to think this is a fool’s errand, there just isn’t enough volume inside ears to allow Steve Rodby’s bass the room it needs to bloom.

M5 bass is deep and powerful, obviously from the same family as the M3 and M4. Sometimes it’s overpowering. I didn’t remember the M3 bass overpowering any songs, but perhaps I was having too much fun with them. There are a few songs which just sounded wrong to me with the M5: “Deeper Well” (I can’t believe I wrote that….), and “Better the Devil You Know” by Me and That Man are a couple of examples. In the former the bass sounds separated from the rest of the music and interferes with the vocals sometimes. In the latter, bass is clear, but so big it makes the song sound bloated and too big. I find it very disconcerting and there aren’t very many songs I listened to which displayed this characteristic. Even stranger is the coincidence that on my audition SD card “Deeper Well” is followed almost immediately by “Easy From Now On” which sounds nearly perfect to me. Go figure.

I don’t want to dwell on those few songs too much, though, because the M5 bass is so good most of the time. So let me not make a mountain out of a few freakish mole hills. Electronic music: Blade Runner 2049 fills my head with pulsing sound. It’s menacing and intimidating. Resonance and hall sound? I’ll refer back to Henry Brant’s Ice Field. The bass drum filled the right side of the hall with booms that nearly echoed and the skins tympani “rippled”. No mere thuds and thwacks here. Sure, poor recordings sounded muddy and indistinct; but good recordings allowed the bass to shine through and often provide more than a droning basso-continuo foundation to the music. I much appreciate that. Rush’s “Limelight” is a good test for this. Neal Peart’s kick drums vie with Geddy Lee’s bass to be front and center in the rhythm section. The M5 do a good job, better than the Rai Penta, Trio or Anole VX, of keeping the two separated.

Oh, “It’s For You”? Nope, I still need a subwoofer in the living room. But a little less with the M5 (it is a smooth rumbling bass riff, after all).

Gestalt, Zeitgeist, Fahrvergnugen (and other German words meaning “the whole enchilada”): Some of this belongs with the conclusions, but here we go anyway. I’ve already noted my discombobulation with the M5 bass. I won’t belabor that point any more. On to some general comments about the M5’s overall behavior:
  • Some of my favorite songs sounded muddy through the M5. James McMurtry’s “Choctaw Bingo” didn’t surprise me all that much, but “Another Brick in the Wall Part II” sure did, it’s the MFSL remastering after all. Damn transducers with reference level resolution: if there’s mud in your recording, they’ll let you hear it.
  • The M5, like the M3 and M4, encouraged me to turn the volume up. But it wasn’t as necessary: I found the M5 to provide a satisfyingly full sound at fairly low volume (less than 50% of full volume on my Mk70 II), while I often cranked the M3 and M4 (and Trio) to 66% of full volume. Richness and fullness scaled with volume, though. The M5 was merciful also, not punishing me with ringing ears or fatigue.
  • The M5 were more relentless than the M4, but not so much as the M3 (or LCD-X). The M5 gives an energetic performance, with lows and highs on an equal footing with the midrange and ample dynamics and articulation to propel the music forward, urging you to listen.
  • qdc Anole VX: A quick note since I had a quick listen to these. I can see why some who have commented the M5 sound is V-shaped. While I was listening to the Anole VX I thought to myself, “If this is linear then the M5 is definitely V-shaped. But then, if the M5 is linear, the Anole is mid-centric.” Vocals were more up-front through the Anole, but at the same time, compared to the M5 the bass and top register sounded quieter. My metal-head friend, who likes leaner bass than I do, preferred the Anole VX to the M5 (and M4), so there is that. The Anole VX does present vocals in a beguiling manner…
  • 64Audio Trio: This time I have a pair of Trio, but am missing the U12t. I’ve already tipped my hand some: the Trio has beautiful treble. The Trio also presents a bit more detail at the top end than do the M5, though the gap is somewhat narrower. I was a bit surprised by this. My expectation was the electrostatic super-tweeter would provide something the balanced armature couldn’t (even if it is naked). In my week with both they turned out to be different means to a similar end. Great execution by both FiR and 64Audio. I didn’t find myself picking nits between the M5 and Trio in the midrange, both were satisfying. As with the M4, the M5 has more bass energy than the Trio. The M5 also reveals low frequency details with the aplomb of the M4 and Trio.
  • “Chitlins Con Carne” by Stevie Ray Vaughn (The Sky is Crying) can no longer be considered serendipitous, since I’ve added it to me audition list. But, it still proved a great way to compare and contrast the M5 and Trio. The M5 comes very close to closing the gap between the M4 and Trio by adding almost the last bit of air and sweetness to the highest highs while maintaining all that long-wavelength energy. It’s a little easier to imagine parting with the Trio and settling down with the M5. Maybe.
  • Meze Rai Penta: What I said about the Rai Penta in comparison with the M3 and M4 still stands. They don’t go as low, and lack the energy and drive of the FiR products. I spent a whole morning listening to the M5, then switched to the Rai Penta in the afternoon. I immediately missed the force of the M5 and, in immediate comparison the Rai Penta sounded muddy. But after a while I got used to the Rai Penta again and remembered the details are still there, I just had to dig for them a bit rather than having them brought to me pool-side. The Rai Penta is self-effacing, the M5 more in-your-face.
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  • Campfire Audio Lyra II: My Lyra II are a good example of what you gain by “climbing the ladder”. I still like my Lyra for all the reasons I bought them: bass, smoothness, the cohesiveness of a single driver, a bit of sparkle on top. Oh, and fit. Who wouldn’t love a little bitty IEM that just nestles in like they do? They just don’t plumb as deep or soar as high. Details are missing. The Lyra II simplify the music in comparison to the other IEMs I listened to. The lowest bass is one-notey in comparison. There isn’t quite as much body or expressiveness in Emmylou Harris’ voice, nor Julia Fordham’s. There isn’t as much air around the instruments, as much room sound. Highs are a bit muddier or splashier, less defined. The soundstage is a bit wider, extending out past the cover plates a bit, though not holographic or all-encompassing.
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Conclusion: I like the FiR Audio M5, a lot. I guess that’s why I am troubled by the few examples I found where the bass bothered me. I wanted them to be a perfect match for what I am looking for. Here is what keeps me awake at night:
  • Are the M3 too much fun to ignore? I’m separated from their bass slam by over a month, but I keep referring to it like I heard it a half hour ago.
  • What about the M4? I’m sure I remember correctly they are more balanced, better all-arounders, than the M3, but how would they fare head-to-head against the M5? Is the M4 bass more controlled than the M5 eliminating the source of angst, and can that tinge of air missing in the M4’s highest register be forgiven when the Trio and M5 are available?
  • And then the outsider (at least outside the FiR family): the Trio. On top of a comfortably familiar signature 64Audio adds THAT treble. Compelling, to be sure. But I do miss the bass rising up and asserting itself as an equal partner in the music.
  • I know I like FiR products, but I don’t know yet which I’d choose to take to a desert island with me.
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