M5 Feature 3

Reviews: FiR Audio M5 (1YR Update): My “If I Could Only Have One” CIEM


“Fir Audio has raised the bar with its M5 offering GOD-TIER, award-winning performance. This CIEM has ticked every box and has scored top-three across the board in every category. It exceeds my personal needs across every use case making it the CIEM that I would choose if I can only choose one. That being said,  is I am proud to award the FIR M5 with our 2021 AudioTiers awards for both our “GOD-TIER” achievement award as well as our “If I Could Only Have One” achievement award.

UPDATE 07/30/21: After listening to my custom FIR M5 for a year now, I had to come back and update my review to give the M5 the full credit that it deserves. The FIR M5 is absolutely my “If I could only have one” CIEM. After a little background, I will break down why I feel this way.

BACKGROUND: Those that know me, know that I have had access to most of the top-tier universal and custom IEMs from the top global manufacturers in the industry for over the last decade through the tours I manage and the reviews that I write. My personal collection of both custom and universal IEMs is extensive as you can view in my HEADFI and AUDIOTIERS signatures which are just a sample of what I have, not all are even listed. I also have extensive conversations with my membership and the top reviewers in the industry and the M5 has not only surprised me but has received the most universal phrase of any IEM I have toured or reviewed. Everyone that I have spoken to without exception has referred to this CIEM as a very special top performer regardless of their signature preferences.

MY TIERING SYSTEM: To break down my experience, I categorize the various top-class CIEMs I hear into 3 tiers – GOD-TIER for the rarified few – the best of the best, TOP-TIER for those that are examples of the best-in-class, and SECOND-TIER for those that are wonderful for specific use cases but not quite best-in-class. Below that, I typically respectfully decline to review. Most are at the lower tiers with a maximum of 5 in GOD-TIER where I place the M5. This list continues to evolve as the bar continues to rise where my previous favorites get pushed down the list. All these CIEMs are over $1000 and can be as high as $5000 now with the price climbing so these are not cheap products and a $5K CIEM is never 5x better than a $1K CIEM so your mileage may vary.

WHY THE M5: As a GOD-TIER IEM, the M5 not only is one of the best of the best but it checks every box. It is in the top three in all my use cases and performance categories across the board and is the top performer in many. Yes, if we get granular there are other CIEMs that can beat the M5 in some performance categories, but for my preferences, the M5 comes out on top for these reasons:

  • Signature: To be fair, the M5 caters to my preferred signature as discussed later. It is onstage and intimate, it is full-ranged and full-sized staging, and it is the most realistic bass I have heard. Others may have other preferences, but the M5 nails mine. When I go to other lower-tier options, I feel like something is missing so the M5 gets most of my ear time.
  • Custom Fit: The M5 is a GOD-TIER option that is offered as a custom which is critical to getting the best fit possible. In fact, it is, unfortunately, the only GOD-TIER option that offers a custom option. While some can get full fidelity out of a universal format, I cannot and always deal with compromise. Those universals that fit me the best still require me to stay perfectly still to enjoy them so they only work with a specific at desk audiophile listening use case. However, most of my listening is active and on the go or laying in bed which is not optimal for universal fit.
  • Performance: There is not a performance category that the M5 is not in the top three and in many cases it is the top performer. Most IEMs focus on an area that makes it unique, there is always an area of concern – scales up but not down, requires lots of power, poor isolation, etc. The M5 allows me to enjoy it in all use cases and seems to not have an “Achilles heel”.
  • Ear Protection: FIR’s 3rd generation atom pressure release system offers a pressure-free listening experience that allows me to turn the volume up without hurting my eardrums. I have tried many companies’ pressure release options with varying degrees of success – most having a downside that reduces performance in some way. There is typically a tradeoff of bass performance, detail, and soundstage that you can have two, but not three. The M5 atom system is the best I have heard offering a cavernous, out-of-head soundstage experience and wonderful bass performance while retaining a very tight note – no compromise.
  • Low-Level Listening: The M5 is one of the few that offers stellar low-level listening performance. The presentation holds tight at low volume allowing me to listen to low volumes at night without compromising performance. The full delicate detail remains even when the volume is down, it just moves me off stage and into the second row offering great performance while listening in bed.
  • Scales Up and Down: The M5 sounds as wonderful on an iPhone as it does on a high-end system. Yes, it does scale up on my best equipment to a remarkable level, but on the road, with my iPhone, it offers top audiophile performance as well on the go. There is more performance out of an iPhone than you can actually hear given the background distractions when moving around in day-to-day life or while working out.
  • Price Performance: Believe it or not, at $2800 the M5 is somewhat of a bargain. If you can afford it, the M5 is on the low side of pricing in the GOD-TIER category offering a high price to performance ratio. Relative to its $5K peers, I am more comfortable taking the M5 with me out of the house and to the gym which I would never do with a $5K option. This gives me more versatility to use it as I would like.

For all those reasons and more, I award the FIR M5 with my “If I could only have one” award as well as the GOD-TIER achievement award. 😊

Full Review

  • Pros: God-tier performance on everything – checks every box, best bass ever, full-sized performance, low volume audiophile capable
  • Cons: Monopolizes your ear time making you less patient with other CIEMs

My quest for the best CIEM started 6 years ago, cumulating into building a full audio tour membership club to be able to feed my addiction with endless tours. Over the course of these tours, I have learned that best is subjective…it depends on your use case. My use cases are on the go, exercise, low volume listening, optimized high-end desktop sources for audiophile best, bass fun, detail retrieval, DAP pairing, genre pairing, etc., etc., etc. This has left room for a number of CIEMs in my portfolio, a whole lot of CIEMS. Each has been optimized with cables and source and genre. Some scale-up, some scale down, some are very specific for a use case.

Then came the Fir M5. It scales up and down sounding wonderful on my iPhone 11, yet scales even higher on my Burson C3R. It sounds wonderful with all my genres, offers bass fun, excels at detail retrieval, and even works great for noisy gyms. It is my “if I could only have one” CIEM. Since receiving it, it has gotten most of my ear time as it is easy to use. My others may scale higher by a little but require a lot of effort to get there with high-end cables and sources and they cost a lot more. The full-sized sound allows me to hear fine details intimately even in a noisy room. As you can tell, I am very impressed with my custom M5.

My CIEM Prospective

For those that don’t know me, I have been hosting numerous TOTL CIEM and cable tours on Head-Fi in the US for the last several years now including most of the top manufacturers ranging from moderately expensive to very expensive options. This has allowed me and my tour participants access to hear some of the most incredible mobile audiophile equipment in existence. Even in the few years that I have been managing these tours, I have seen significant advances in technologies and performance to the point that it is rare to hear any product at this level that I do not like. They are all different in signature appealing differently to different people, but they are pretty much all very good at this point. So when I am raving like I am about the M5, this is in the perspective of most of the top-tier IEMs from the last 6 years. To learn more about me, you can follow me on HEADFI where I go by username BARRA or you can go to my https://audiotiers.com/ tour membership site where you can even join my tours. 😊

What is the Deal with Fir Audio

While Fir Audio seems to have come out of nowhere and reached the tops of the performance charts overnight, there is a lot of history behind this achievement. The founder, Bogdan Belonozhko, is one of the Belonozhko brothers of 64 Audio fame. He brings with him the knowledge of 64 Audio performance, but with a twist. With his M5, he has created a tribrid CIEM before 64 Audio has come out with theirs. If you have heard any of the stellar 64 Audio products, then you probably have high expectations for the Fir Audio lineup and based on what I have heard and the reviews I have read, Bogdan has delivered. This is why I reached out to set up a tour so we can all hear them for ourselves. If you are interested in joining the tour to hear for yourself, go here: https://audiotiers.com/fir/.

The FIR Family

As seen in the graphic below, the FIR family is 4 IEMs strong and they share a family sound. As you can see from the configuration chart, they all share that same dynamic driver that brings the signature to life.

From my FIR tour, I was able to listen to all these siblings side-by-side and found quite a value in the lower-priced options for those that cannot afford the M5. Here are my early listening impressions to offer you a comparison:

  • M5: Nailed it! This is that big bassy sound that I have so been craving. Yes, it rivals my EE LX as the bass king with a different take on bass. My first impression is WOW as it is that different than my other CIEMs in a good way. The sound stage is huge, with players/instruments huge as if I was there. While this is not as warm of a signature as my LX, it is more intimate and close-up for in-your-face fun. Yet it checks all the boxes for audiophile performance. This reminds me a bit of the A18 with the M20 module, but with better bass and lighter treble. I Will be doing a full written and video review on this one so hang tight for comparisons and deeper insights. 
  • M4: The M4 is extremely close to the M5 with more of a treble presence. All the bass is there, but the treble stands out more with more splash, sizzle, and air without ever being harsh. But going back to the M5, it is not missing any of this detail, just not as pronounced and more integrated. This is a great option to save some cash for treble lovers that want that M5 bass.
  • M3: Again, that same bass driver is delivering the goods with a well-defined house sound. The M3 is close to the SQ of the M4 but set back a little maybe one section back. While I prefer the M4’s more intimate signature, the M3 is pretty darn close in sound and retains the M4’s larger treble presence.
  • M2: This was my biggest surprise and the greatest value play in the lineup. It has all that bass goodness the rest of the more expensive models boast which makes this lineup so much fun. However, the signature becomes more intimate closer to the M4 than the M3. While I do think that the M4 and M3 have more detailed performance, you would not notice without an A/B sampling as it feels like I am splitting hairs. 

End-to-end all models have that same wonderful bass driver that is very distinctive. The M5 stands out as more refined using the EST top-end drivers, but there are many that prefer the BA treble splashiness and could prefer the M4. The M2 is remarkably close in signature to the M4 with a little less detailed presentation and screams value. Don’t just take my word for it, join the tour and see for yourself.

Overall, I have to say that we are dealing with another CIEM manufacturer that is continuing to drive the top-tier bar even higher. Yet they have carved out a new signature that is unique to the other manufacturer’s offerings that will definitely drive some solid sales. This lineup is a must-hear if you are considering a CIEM purchase.

Tour Kickoff Video

To give you a better perspective on the family, here is my FIR tour kickoff video that shares the universal tour kits and my experience with them.

The Custom M5 Unboxing and Impressions Video

To give you an understanding of the M5, I felt it is best to start out with some video so you can see it for yourself.

The Order Process

Having ordered a number of CIEMs, the lack of ordeal here is a great thing – boring is good! The entire process can be handled online offering WIZIWIG support on the custom designer. The material options are good, and the process is easy to follow end-to-end. Best of all, there are no language barriers nor time zone issues. Over the years, I have had a number of less than optimal experiences so having a seamless experience like this is wonderful.

Here is an image of what I designed:

Here are the results:

Fit and Finish

My ears have a weird bend in the inner ear that makes listening to universal IEMs…difficult. This means that I often have to cup my ears or stay perfectly still once I have achieved a perfect seal. This has moved me to mostly choosing custom fit in-ears. This is a process of going to an audiologist and having impressions made – per FIR Audio’s specific instructions – then hoping that the impressions are good enough to use once received. Having found a good local audiologist, I am most certain of a good impression, but there is also a bit of craft and secret sauce from the side of the CIEM manufacturer that can vary the results. For example, Empire Ears creates a smaller mold that is easy to insert while Vision Ears offers a larger mold that creates a suction when inserted or pops when removed. Both work great, but the tighter the fit, the more the frequency range is expressed, and the loser, the more comfortable but susceptible to outside noise. FIR meets the middle ground with a nice fit that is easy to insert but creates a nice suction for full-range sound.

The finish is outstanding. As you can see in the picture, it is a polished gem and there are no sharp edges anywhere. The “ATOM” module you can see on the face requires more finesse than the typical faceplate, but they offer an outstanding finish. This is a medium-sized mold so it is compact and easy to insert and has a recessed port with a screen to offer wax resistance.

ATOM (Air Transferring Open Module)

64 Audio being one of the originators of the air module design, it comes as no surprise that Bogdan has brought his own version of the technology to his company. These modules in all their formats and under all the different names all have a single purpose, to protect your hearing. By releasing some of the pressure in an optimized format, your eardrums don’t take a beating that has always been a concern with in-ears. My M5 came with three modules – black, grey, and gold.

In practice the modulation of the air pressure does two things for those CIEMs that offer it:

  • Sound Modulation: Many manufacturers including FIR offer a variety of modules that offer different sound enhancements. Some are closed offering a larger bass, while some are very open offering more of an out of the head experience.
  • Higher Volumes: Due to the pressure system, volumes can be increased offer many advantages such as a fuller sound without discomfort.

The ATOM XL 4pk is an offering of additional modules that can be used to shape your sound to your liking.

From FIR:

“atom (air transferring open module) is the 3rd generation module technology that was specifically designed to give the user maximum control with front vented In-Ear Monitors. Boasting a bass tolerance of 1/2 dB makes these modules the most advanced way of fine-tuning that perfect sound signature you’re looking for. A smaller filter design reduces the air volume in the module chamber which can have a positive effect on sound presentation. The 4 pack set comes with an assortment of +, N, -, O (plus, neutral, minus, open). Durability was a high priority with the atom design. Filtering using precise medical grade tubing allows for a consistent production process. atom is also immune to shock from accidental drops and even humidity. Isolation levels vary among the modules relative to the bass leak.”

ATOM Specifications:

  • (+): Isolation: 17db, Bass: 2db @ 20hz
  • (N): Isolation: 15db, (m15 equivalent)
  • (-): Isolation: 13db, Bass: 2db @ 20hz
  • (O): Isolation: 10db, Bass: -4db @20hz

M5 Tribrid Specifications

As can be seen in the FIR family graphic, the 5 in M5 stands for 5 drivers – ESTAT-high, BA for high, mid-high, and mid, then a dynamic driver for the lows. It is a true tribrid. Here is what FIR has to say about the M5:

“The M5 is the showcase of all the best technology FiR has to offer in the IEM space. Sporting a dynamic driver for lows, 3 balanced armatures for midrange and highs, and an electrostatic driver to assist the treble reproduction, the M5 maximizes its driver count to present an effortlessly massive sound, with shocking clarity and extension on both ends. We’re also proud to be the first in the world to implement the electrostatic drivers, in addition to all the other drivers in the M5, in a tubeless design, paired with the 3rd generation atom pressure release system to provide the M5 with a cavernous, out of head soundstage and a pressure-free listening experience that is well suited to all professional and audiophile use cases.”

DYNAMIC BASS: The interesting part for me in this configuration is the dynamic bass module. The M5 is holding the top spot for bass with the EE LX, but both are very different in presentation. The LX is warm and laid back while the M5 is tight and huge without stepping on anything else in the frequency range. There is a clarity that comes with the M5 that you don’t ever hear with bass this big. No, not fart cannon big, but full-sized audiophile speakers in a $100K setup big. We get a full-sized foundation immediately so that the other frequencies are not strained when raising the volumes to reach realistic sizing. I did my best to get some clarity on how this is possible, but all I got from Bogdan was that this is a 10mm dynamic driver with some secret sauce tuning. This is a bigger driver than all the other top-tier CIEMs with the exception of the Noble Sultan that shares the same size with different results.

ESTAT: The ESTAT is here to stay. Having heard a number of implementations, when done right, there is an exceptional clarity that cannot be matched by the older BA sound. The goal here is butterfly wings delicacy with oozing detail that if done wrong can be too sharp or even bright. It is fair to say, FIR got it right. Balancing out the huge audiophile bass with butterfly wings delicacy and detail is quite a feat.

DRIVER FLEX: None. There seems to be a lot of conversation about this topic in reference to dynamic drivers so I thought I would confirm that I have not heard any driver flex with any of the FIR family lineup. Perhaps this is due to the ATOM modules managing the air pressure.

 Other Specifications:

  • Range: 10hz – 20Khz
  • Impedance: 6.8ohms

The FIR Family Cabling

FIR went proprietary RCX on the cabling. While this is a bummer for us cable rollers with an investment in high-end cables, the cable is great and I have not felt an immediate need to upgrade as I have with many others. While I will explore a little cable rolling later and I am likely to pick up an adapter available from FIR later to enable further cable rolling if I ever get adventurous – for now, this cable is good enough.

The value of two-pin is that it is widely accepted, but I also have issues swapping cables too much as the hole that you insert the cable pin into does wear out and stretch creating a significant problem down the line. Therefore the MMCX and the RCX were developed to create a better connection as well as the ability to swap out cables without damaging your CIEM. However, the 2-pin seems here to stay which is moving us toward adapters such as this RCX 2-Pin Adaptor available on the FIR website. What is troublesome though is the price. At $79, it is a deterrent for many…at least until the stock cable breaks.

My experience with the RCX cable connector is actually quite good. It clicks on with a good click giving you confidence that you are securely connected and remains tight. This and the MMCX are preferable to me if I wasn’t already stuck with 2-pin on my entire CIEM collection.

The M5 Sound

When describing the M5 sound, the first thing that comes to mind is its full-sized presentation even at lower volumes. The second is that wonderful audiophile BASS richness brings the sound stage to life…that being there feel. Then finally, the in-your-face detail from the mids offering butterfly wings to thick textures is what makes it so enjoyable. While most CIEMs with bass this big would be on the warmer side of neutral, the M5 has an intense clarity to it with large staging that allows the details to take center stage.

BASS: The M5 is my favorite bass CIEM along with the EE LX. The EE LX is set back, laid back, and calm where the M5 is more center stage, on your feet, and dancing. This bass starts big at low volumes so that it is present for my nighttime listening offering a much richer sound than I can get from my other CIEMs at that volume. The ATOM pressure regulation makes it easy on the ears as well so again, this is a wonderful low volume CIEM that I prefer for my nighttime listening. My other CIEMs need too much volume to sleep comfortably to reach that level of performance. Going to full-on EDM, that 10mm driver pounds and has become my favorite EDM CIEM. Scaling up to my high-end desktop equipment such as my Burson C3R or my Eddie Current ZDs, the bass gets even better with a tighter and more powerful response with a larger soundstage to enliven. Again, this is the top-in-class bass which I will compare later to other top-tier options.

MIDS: Given my description of the bass, you would think this was a warmer driver that would sit on the mids, but no, the mids are what I like so much about this CIEM. At low volumes, the voices are all full-sized and upfront and center making them rich and offering gobs of in-your-face detail. In sizing other drivers, I find that the mids fall apart when getting to the right volumes, however, here on the M5, turning up the volume just scales up the details as you would expect from the top-tier audiophile equipment. As mentioned, the mids offer butterfly wing details as well as thick textures at the same time with the separation to hear it all simultaneously.

TREBLE: Going back and forth between the M5 with the ESTATs and M4 with the BA driven treble, the BA treble sounds splashy while the ESTAT treble sounds delicate and airy. While the BA treble offers that SHHHHHHH, the ESTATs can bring out the most delicate textures. In fact, the ESTAT implementation with the M5 is so good, it doesn’t call any attention to it. What it does is layers the presentation with additional detail in the mids and the bass. It is so good that the treble goes somewhat unnoticed. With the drier treble, there is a lot more room in the soundstage to bring out the more important details which the M5 does in spades.

PRESENTATION: The M5 feels like it is either front row or on stage in its presentation. It is a very intimate affair. I hesitate to say intimate as it is not closed in as that may imply, but more like you are in the middle of a larger theater on the stage in the VIP section.

SOUND STAGE: The stage is large, but it is deeper than wide giving the impression that it is narrow. But if you listen, it is not narrow at all, just very layered with the Important voices up close and personal. However, there is a large ambiance, that sucks you in with access to other things going on in the room, as you might hear in live performances. There is clarity and space between voices that allows great staging. I wouldn’t go with a black background with this CIEM as there is such rich depth and depth cues that sometimes offer a holographic feel.

SCALING DOWN: My M5 sounds wonderful on my iPhone. Going bike riding is a real treat. I am amazed at how well it scales down, even better than my A12. This is a big driver to sound so good on so little power. I typically find that dynamic drivers don’t do so well on low-powered lower-end gear like the iPhone.

SCALING UP: My favorite source for my CIEMs is currently my Burson C3R which takes them to the stratosphere in performance. If I want to know just how high they can fly, the Burson is my go-to setup. In comparison to the much more expensive ERL or THUMMIM or the WRAITH, SULTAN, the M5 holds its own. The ERL peaks out with great DAPs with its BA design and can beat the M5 at that level, but the M5 peeks higher on the Burson where the ELR falls apart. The THUMMIM can beat the M5’s performance on the Burson, but cannot keep up using DAPs as a source. The ERL and the THUMMIM are almost double the price. We will all have varying opinions at this level as they are all stellar and offer different takes on a presentation that will appeal differently to different people, but I think we can all agree that these mentioned CIEMs are top of the class and the M5 belongs here. In scaling up, it is the power that the M5 gobbles up to produce exotic performance and the Burson offers it in spades at 7.5 watts.

BURN IN: I thought I should mention that the M5 has benefited significantly from burn-in. While I was wowed out of the box, my review kept being pushed back as I found the performance accelerating over time. While not a total believer in burn-in, I do provide some burn-in time to all my review items to support those that do believe in it. However, I do find that dynamic drivers do benefit from being exercised to loosen up the driver. For example, the iPhone was a loser at first as there was too much driver flutter. After a month, the M5 became my best pairing with my iPhone 11. I also found that the M5 scaled up with the Burson easily with its greater grip of the driver believing that was required, but it turned out that this exercising of the driver was all that was needed. It took a month of continual usage before I felt that there were no longer gains.

HISS: Given the low 6.8-ohm impedance, I am often asked about hiss. However, I’m probably not the right person to ask about hiss as I am over 50 and cannot hear treble like I used to. Regardless, to my ears, there is no problem with hiss on my WM1a, H2, Calyx M, iPhone, or Burson.

PAIRING GENRES: Given its intimate nature, it is surprising that the M5 is actually very good across most genres. It is great at EDM as you would imagine, but it is also really great across the newer fresher sounding pop, instrumentals, easy listening, classic rock, and pretty much everything else that I throw at it. Specifically, it is most amazing at live, guitar-focused, or bassy music with incredible texturing and detail. If you would want to sit at the front row of a performance, then the M5 is the right CIEM for you. However, orchestra and opera where you may prefer to sit in the upper balcony to take it all in and enjoy the wider soundstage, the Legend X might be the better choice.

ADJUSTING TO ESTAT: There is no ear fatigue with the M5. I bring this up as it took me three solid days of listening to the Valkyrie and the Wraith and their ESTAT implementation before I got used to the ESTAT sound. However, as mentioned earlier, going between the M5 and M4, I am an ESTAT believer and will likely favor ESTATs going forward.

Optimizing and Pairing

The M5 sounds great out of the box even before burn-in and the cable is wonderful. However, audiophiles such as I rarely leave good enough alone. After a couple of months of stock setup, it was time to stretch the M5’s legs. Here is what I did describe below.

Optimizing Cables

In the end, the stock hybrid Effect Audio cable that came with the Valkyrie was the best pairing to my ears. It is a surprisingly good cable to be offered as a standard. While experimenting, here is what I found:

  • Moon Audio Black Dragon ($200): This is the thickest sounding cable of my collection and not a great match. I felt like it muddied the signature and preferred the stock cable.
  • DITA Audio OLSO ($599): This is a unique oiled copper cable from DITA that really adds to every CIEM that I have paired it with. However, it added a little much with the M5 making the bass too much and created more clipping on lower power sources like my iPhone. It also brought up the treble too much which did change the M5 to more of a V-signature with recessed mids. This is not what I was looking for either.
  • Beat Audio Prima Donna 8W ($1199): The Prima Donna is a silver alloy 8 wire cable that has wowed me on all my CIEMs offers significant clarity and additional dynamics. However, on the M5, it is just not a great pairing as it added too much treble and it muted the bass.
  • Effect Audio Eros II ($279): This is a surprisingly good stock cable. As a hybrid, it provides the best of the copper thickness and the silver detail to emphasize all the right characteristics of the CIEM. The resulting SQ is very flat and audiophile with gobs of treble and sub-bass detail providing layering for the mids. I don’t have any other hybrid cables currently to compare apples for apples so Eros II has won a place in my heart and will stay on the M5 as long as I have the adapter.
  • Stock M5 Cable: This cable was a win as it sounds as good as any of the others I tried. The only concern was that it tended to get unstranded over time making it look messy and potentially may break. However, the sound won me over, and having lost the adapter, will remain on the M5.

UPDATE: I ended up picking up the FIR adapter so that I could roll cables again. At the end after much experimentation, I found the Eletech Iliad to be the best pairing and is what I am using today. The Iliad doesn’t change the M5 signature at all, but just seems to allow the M5 to do everything that it does well…better – a definite level up that I can feel if I ever take that cable off. If you can try it, please do, you will not regret it. 😊

Scaling Source

While the M5 sounds surprisingly good on everything, there is a difference in results worth discussing. Here is what I found:

  • iPhone 11: Amazon HD Music is a new app on my iPhone that has improved my sound quality considerably. From the standard Apple Music app, the M5 sounds great, but better on my better DAPs. The new Amazon app takes this up several notches and gets the iPhone closer to my dedicated DAPs mentioned below. In fact, the music discovery on the iPhone has made it my preferred method to listen to the M5 on the go. Either way, the music sounds full-sized from the iPhone, just more filled out with the Amazon app. But the dedicated DAPs are clearly better overall. I just wish that I had access to the Amazon music app with these DAPs. As mentioned above, the only weakness of the iPhone is that in crowded or dynamic passages there can be some clipping at first. However, for whatever reason, the clipping seems to disappear, and the fullness of the note returns after the iPhone warms up with 15 minutes or so constant playing.
  • Calyx M: The Calyx M is famous for its sound quality implying that the 9018 is responsible. While the stats don’t speak to this, the amp is likely to be the bigger influencer burning up a giant battery in less than four hours to meet that quality output. The clarity and transparency offered in the colder Calyx M signature offer more detail than the Sony below. In comparison, I used to like the Calyx M better than the Sony until I got a custom firmware upgrade on the Sony. The Calyx takes the audiophile performance up a notch with more and tighter detail, while Sony can actually be more fun. An advantage the Calyx has over Sony is that volume slider that allows me to perfect the volume for each song instantly and to play the M5 louder than normal for short bursts.
  • Sony WM1a: The Sony was almost sold last year as it didn’t pair well with my CIEMs until I got the new custom firmware. The new firmware now plays nice with all my CIEMs. The M5 is a wonderful pairing offering a warm performance with a nice girth to the note and more resonance and textures. The Sony with its superior battery life and UX is my go-to DAP for the M5.
  • Hugo 2: The H2 takes the experience up a notch with a better DAC and AMP. The pairing is more in line with the Calyx M but on steroids. The bass comes out more, the detail is at another level, and the sound gets fuller. However, as with the M, the H2 brings out the clarity/transparency of the M5 for more of an audiophile sound rather than the more fun Sony. The problem with the H2 is that it is a stack that is not always convenient, so this is not as normal of a pairing as the Burson C3R which takes it up another notch given the additional driving power if I have to deal with the inconvenience.
  • Burson C3 Reference: Going desktop, the Burson C3R is my favorite pairing supersizing the overall SQ significantly and in a fun musical way that crushes the Sony. It should also be mentioned that I am employing the Amazon HD Music application as a source and running it through my Sonarworks True-Fi application tuned to my HD800 headphones that work well with the M5 signature. Playing through iTunes with True-Fi turned off brings down the sound quality noticeably, so some may consider this a cheat. Regardless, the C3R drives 7.5 watts into the M3 6.8 ohms, so the volume stays between 1 to 5 out of 100 steps.


As mentioned in the beginning, I have a great collection of CIEM from which I judge all newcomers. Besides having access to all the TOTL CIEMs in my tours, I have accumulated a nice collection of my favorite including – Thummim, ELYSIUM, Legend X, A18 Tzar, Valkyrie, Hidition NT-6 Pro, A12t, Aether, Fearless S12, and others. To offer some insight into the performance here, I will compare the M5 to my best below:

  • Thummin: My other GOD-TIER IEM in my personal collection is the Thummin. I compare this IEM to the ABYSS in a number of ways. One, it has the same signature and is as exotic-sounding as an IEM as the ABYSS is a full-sized headphone. However, both require a great system to reach their full potential and can sound dull on a lessor system. When driven properly on my Burson C3R, the Thummin is the best sounding IEM that I have and yes, it does beat the M5 in this use case. However, the M5 is not far behind, even driven by a lessor setup. In this case, I would compare the M5 to the Audeze LCD-4 – another exotic headphone that is close in sound quality.
  • Sultan: The Sultan has received mixed reviews, but I personally insist that it is one of the rarified GOD-TIER IEMs when driven properly and with the correct seal. While this one is not currently in my collection, I have auditioned it extensively and will speak to it the best I can. I would compare the Sultan with the exotic STAX OO9 electrostatic headphones. The Sultan has the same ability to extract an exotic amount of detail putting it at the top of the class in detail retrieval. Unlike the 009, the Sultan also has a very present and natural bass response which never steps on the detail. The 009 has nice bass, but it seems more distant with the treble more present. The Sultan is definitely treble first, but not at the expense of a fantastic base response. The M5 is more like the Thummin than the Sultan – the Sultan being a very different Audiophile signature that is all about the detail. While the M5 oozes detail as well, it is a more fun first warmer ride. These two IEMs are very complementary offering a great variety for your various genres offering two different presentations so you never get bored.
  • 64 Audio A18: The 18 was the detail monster that I used to judge all others. That being said, it has a variable signature which I have standardized with the M15 APEX module that is more analytical and my OLSO cable to maintain that performance while bringing up the bass a notch for a richer character. The 18 has a well-deserved place in the top TOTL CIEM tier and is likely to remain there for a long time. While its perfection quickly impresses, this perfection is also its greatest weakness as it can get boring over time. For this reason, I have collected a range of CIEMs that I rotate to keep my interest high. Compared to the M5, the 18 is showing its age. The M5 has that something special and is more fun leaving the 18 wanting. This is not saying that the 18 is bad as it is a great CIEM, but that the M5 is just that much greater in performance and that the bar for performance has risen in the last half-decade since I got my custom 18.
  • Legend X: My X has been my most listened-to CIEM until the M5 arrived. Going back and forth, there are two very wonderful signatures that are very complimentary and different allowing both to sit prominently in my collection. The X takes the warmer side of the road making all music fun and rich. It makes mediocre music sound good. However, the dual subwoofers in the X are the star of the show. While they only show up when called for, my tendency is to listen to music that calls for bass when listening to the X because it is so much fun. The treble and mids and soundstage are wonderful as well reminding me of the EE Zeus when the bass is not called for so there is nothing bad to report for the X. However, the M5 bass is more intimate where the X bass is laid back and set back. The M5 is in your face on stage while the X is sitting back at the front of the first balcony. I love my X for casual listening, but the M5 is more energetic making it a great daytime driver and the X more of my nighttime listen.
  • ELYSIUM: The ELYSIUM has the best mids period with a dynamic mid-driver. It also has an EST treble set up with a single BA for lows making it a tribrid as well. However, the ELYSIUM and the M5 couldn’t be any more different. The M5 is full-spectrum, energetic, and onstage where the ELYSIUM is intimate as well, but emphasizes the mids. In comparison, I would say that the ELYSIUM is my go-to for vocals where the M5 is more fun and an all-rounder. Like the X, the ELYSIUM is more of an evening listen now that I have the M5 to take over my on-the-go duties.

Concluding Thoughts

I find that about 70 percent of my ear time goes to active on the go listening while I exercise or run chores in or out of the house, with only 10 percent going to nighttime audiophile listening when I get a chance with the other 20 percent listening in bed. While I want top audiophile SQ for all three types of listening, for active listening I prefer a more energetic signature with more bass to compensate for the noise and distraction and also to put a hop in my step and wake me up. At night for audiophile listening, I prefer a bigger soundstage with a gentler audiophile tuning to pull out every last ounce of detail. For in-bed listening, I need a low volume performer that doesn’t sacrifice SQ for low volume. The M5 somehow manages to offer top performance in all three use cases. This is why it is becoming my go-to CIEM for all my needs getting more ear time than any other in my collection.

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03/23/2023 2:45 am

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03/23/2023 2:47 am