Audeze MM-500: Master of None

Before I talk about MM-500, I need to talk about LCD-5.

I don't love Audeze's most recent flagship. I can appreciate that they wanted to make something smaller, lighter, and more "normal" sounding than previous flagships... but it neither excites nor immerses me as much as Audeze's former flagship LCD-4.

LCD-5 doesn't have the same dynamic capability as LCD-4, and it doesn't have the same rich timbre of the (good) LCD-4s I've heard either. So when I saw that Audeze's new MM-500 shared a similar chassis design and tuning philosophy to the LCD-5, I was a little worried that it would fall similarly flat for me.

While the LCD-5 seemed to leave most of LCD-4's best features on the operating table amid its weight-loss surgery, the new MM-500 wrangles back some of LCD-4's more decadent aspects. MM-500 even shows up the flagship LCD-5 in a few ways, by having a more coherent and pleasant tuning overall, as well as better build and comfort.

MM-500 has the distinction of being the first headphone by Audeze explicitly targeting the pro-audio use case. As someone with a smattering of experience in the field, I wanted to approach this review in a way that I haven't with any of my other reviews. I want to accommodate readers from both sides of the musical coin—the producers and consumers. I’ll touch on the usual subjects, but I also want to extend some of the knowledge I've found in this hobby to the pro-audio people who are less familiar with audiophile terminology.

I may have learned to listen for specific frequencies and dynamic swings/transient definition due to my pro-audio ear training... but I credit the audiophiles with teaching me how to communicate about sound, identify properties of transducers, and relate my experience of transduced sound to its real life counterpart. The audiophile hobby is not about production, but reproduction. I had to learn (and importantly, unlearn) a lot when I started hanging around the audiophiles. Here's hoping I can help at least one audio professional out there learn something new while also giving my thoughts on how MM-500 fares as a product for the audiophile and pro-audio use cases.

Testing Setup

As always, the MM-500 was tested on a few things.

• Apple USB-C to 3.5mm Dongle
• Meizu MasterHiFi USB-C to 3.5mm Dongle
• Dangerous Music Source (DAC paired with in-built headphone amp)
• Dangerous Music Source (DAC) -> Bryston BHA-1 (Amp)

I immediately found MM-500 to be less source-sensitive than the LCD-5, but in many ways this is a benefit not a detriment. It's easy to drive as well. I found MM-500 sounded slightly bigger, deeper, and less sterile on the BHA-1 + DMS combo, so that's where I ended up using it most often while evaluating.

Build/Comfort

If you're familiar with the LCD-5, MM-500 is extremely similar save for a few important differences. Instead of the acetate for the outer ring and carbon fiber for the headband, the MM-500 uses aluminum for the main chassis and spring steel for the headband.

These choices in the aggregate increase the weight of MM-500 moderately compared to LCD-5 (my unit weighs around ~500g). It also has the benefit of increasing the perceived quality of build significantly. Part of what I love so much about the larger LCD series offerings is how stalwart they feel in the hand. The addition of various metals here gives MM-500 an edge over LCD-5 in that feeling of sturdiness, as well as in my hopes for its potential longevity.

Importantly, the pads no longer make contact with your head in a small, almost triangular cross-section around the circumference of the pad. They instead look almost identical to the older LCD style pads, just smaller (which means increased surface area making contact w the side of the head).

The implementation of spring steel for the top band has the added benefit of allowing the end user to stretch the headband to adjust the clamp of the headphone. This is especially nice because—despite the shocking weight savings— the most common complaints about the LCD-5 were due to discomfort caused by the clamp and earpad shape. In going back to a more orthodox pad design with more pad area making contact with the side of the head, as well as the spring steel band, they've addressed both of these issues... for the most part.

A big complaint here is that the suspension strap is pretty much always too short on all of Audeze's headphones. I understand why they don't want to make head straps too short, as doing so would make the clamp even more dramatic for what is perhaps the average user, but it's one aspect that has soured my experience with their headphones in the past and it's present here too.

Even worse is that the new MM-500 head strap—unlike the LCD straps prior—cannot have holes drilled further up the band to increase clearance between the headband and the head strap. The only solution for many users here is going to be Audeze manufacturing a smaller head strap for those of us with smaller heads. Hopefully they are open to the idea, because it comes dangerously close to ruining what is otherwise a very pleasant comfort equation here.

Visually, MM-500 is probably one of the nicest looking headphones I've ever seen. While I found LCD-5's aesthetics to be kind of tacky, the MM-500 is all business. Grayscale, metal finishing, and the new streamlined chassis design mean that—aesthetically—MM-500 is a home run for me. I gather it will be for a lot of people.

Unfortunately, the comfort is much more of a mixed bag, but it hasn't stopped me from wanting to use the headphone a ton. Let's talk about why.

Frequency Response/Tonality

Measurements of the unit being reviewed here can be found on my squig.link.

I've got to hand it to Audeze... they've done great work here. This is easily their most well-integrated frequency response to date.

Not only does the MM-500 abide by our known preference targets exceedingly well, it abides by my own unforgiving Head Related Transfer Function (HRTF) better than most of the headphones I've heard.

I'd go as far as saying this is my favorite stock frequency response I've heard from any planar magnetic headphone. When it comes to listening for enjoyment, the only real issue for me with the stock tonality is a small bright spot around 14kHz (which seems to go away as the pads compress on my head over time).

Unlike most other headphones in the audiophile hobby though, MM-500 is explicitly targeting those working in the pro audio sphere. For that specific target audience, the answer gets a little more complicated and there are some problems I could foresee for the end user.

Before we go deeper though, it's worth reiterating:

This is the best frequency response tuning I have yet heard in a planar magnetic headphone.

Well done, Audeze. Now let's dive in.

Bass

Unsurprisingly, MM-500 extends in a linear fashion into the infrabass as you might expect of any Audeze planar. Extension is likely the most important factor in a headphone for the professional use-case, so I'd say this aspect of the bass is done well. However, the whole of the bass tuning isn't what I'd call entirely ideal for its intended use.

If we're supposed to be emulating what consumers are listening to, or serving as a stand-in for speakers in a room, we'd likely see some sort of elevation below 240Hz. Most transducers being used by the average listener, whether it be a headphone, earbud, IEM, or speaker, will have a rise somewhere down there. This will occur due to:

• Driver resonance frequencies on earbuds like AirPods, dynamic over-ear/on-ear headphones, underdamped planar headphones with front volume leakage, etc.

• "room gain" : a bass elevation imparted to speakers when placed in a room or near a wall

• Intentional tuning. This mainly applies to "closed" systems like IEMs and closed headphones, as it's hard to get a distinct bass shelf in other systems.

In a study by Jeroen Breebart, it was found that the "average" over-ear headphone actually is quite emphasized in the upper-bass/low-mids, as shown below relative to an earlier version of Harman's target curve.

This leads us to a simple truth that unfortunately undercuts MM-500's utility as a studio tool in its stock formation...

Most people aren't listening on systems with flat/linear bass.

Audiophiles are a niche, and sealed-front planar enjoyers are a niche within that niche. Most consumers are listening to music on transducers with non-linear, usually boosted bass responses, so the bass presentation here—while technically linear and subjectively palatable—isn't 100% ideal for the pro audio use case unless it serves as a reference specifically for linear bass.

That being said, what the flat bass does afford the end user is the ability to add a bass shelf wherever they might want it using EQ. It's a tradeoff between something being potentially more usable out of the box vs. being able to be adapted to whatever the user prefers, and MM-500 being a sealed-front planar basically goes for the latter by default. Both have merits and detriments, but I think the former choice of a well-tuned bass emphasis is usually going to be a better choice. Even when the audience is mix engineers, you can't expect all of them to EQ.

Midrange

The lower midrange (<500Hz) has the predictable problem of lacking contrast or slope relative to the bass below it. As such, instruments with sub-300Hz fundamentals like male vocals and snare drums seem a little off. They favor their first few harmonics a bit and sound just a little swollen. Snares sound slightly too chesty and cuppy, while lacking in heft.

I think besides the lack of clockwise slope into the bass though, the low midrange here is ultimately going to be pretty even good sounding for both audiophiles or audio professionals. That small ~450Hz dip actually does a good job providing some contrast between low-mids and center-mids and stops things getting too boxy.

The center midrange between 500-1000Hz shows a slight forwardness typical of many headphones, whether they be planar magnetic like Audeze's LCD-5, or dynamic driver headphones like Sennheiser HD600, Focal Utopia or Aurorus Borealis. One of my favorite things about this tuning is that this center midrange bump has been reduced just enough to take the sound from the realm of LCD-5's "annoyingly lean and mid-forward" signature, to something more akin to the HD600's "this has a nice sense of forwardness to vocals".

Even some of my favorite dynamic headphones like the Utopia and Borealis haven't quite gotten the tuning in that area under control compared to MM-500, though I concede the Utopia and Borealis are more textured in the midrange due in part to that bump.

The midrange elevation continuing through to 1.5kHz on MM-500 is definitely there though, even if it's reduced vs. LCD-5. It adds an additional "throaty" texture to things like electric guitar and bass, while also at times making horns and strings sound somewhat unnaturally pinched. I think this boost's most notable added character is that vocals are always brought front and center. It's great if you like vocals, but perhaps not an ideal fit for every vocalist, as certain female vocals can sound too clenched and heady. This again is mostly a nitpick, as many of the headphones I like very much don't present this area perfectly, save for the HD6x0 series from Sennheiser.

Speaking of which, the upper midrange is right around where I and many Sennheiser fans will likely prefer it: Harman 2013 from 1.5kHz until around 3kHz. Importantly for me though, it centers its peak right at 3kHz instead of closer to 3.5kHz like the Sennheisers or LCD-5, while also having significantly less 4-5kHz. The latter area is an spot I've found responsible for a somewhat grainy quality (and also an area of massive variance) on the 6x0 headphones, and has gone far enough to keep me from owning one.

That being said, the 6x0 headphones are still the absolute midrange kings. I'm not sure there's a midrange in any headphone, regardless of price, that I find more faithful-to-life and natural sounding. This may be, in part, due to its adherence to Harman's 2013 target.

A Brief Tangent for the Pro Audio Readers

To further educate the pro audio crowd here who might not be familiar, the Harman Target Response (specifically the 2013 curve shown here) is a headphone preference target derived principally from the measurement of a speaker on a dummy head microphone—otherwise known as Head and Torso Simulator (HATS).

Harman's researchers took a good speaker and placed it in a well-treated, good sounding room. They EQed it flat in that room using a measurement microphone, then used a HATS (modified GRAS KEMAR) to record the flattened speaker's response in the room to capture how a "flat measuring speaker" might actually measure to the human ear.

Perhaps surprisingly, a speaker made to be flat measuring in a well treated/good sounding room sounds... not the best. So, since this was a study centered around listener preference, the speaker that was EQed flat in the room was subsequently "tilted" with low shelf and high shelf filters as chosen by numerous listeners (trained and untrained) to tweak the speaker's response to their preferred sound.

Finally, the values of the low and high shelving filters chosen by listeners were averaged and applied to the original "flat in-room" measurement taken by the HATS. This resulted in a curve that was tested to be greatly preferred vs existing targets used for headphones (Diffuse Field and Free Field among the two most often used prior). This showed that these shelves when applied to the "flat in-room" speakers were preferred similarly to the way those same shelves were preferred when used in headphones. This resulted in the 2013 Harman curve being born.

Since this target response is derived necessarily from "what people prefer a speaker in a room to sound like," something measuring close to this curve on a HATS at minimum gestures towards meaningful correlation to the idea of a "good sounding speaker."

For those working in the pro audio space, this is a hugely beneficial thing to have in the form factor of a headphone instead of, well... speakers. And this is MM-500's least ambiguous benefit to those in the pro audio field.

If you need something to give you a reasonably speaker-like midrange while you are on-the-go, in hotel rooms, or in unfamiliar studios, the MM-500 unquestionably delivers. In fact, it does so better than most other planar magnetic headphones, regardless of price.

Audeze deserves quite a bit of praise for the midrange in the MM-500. It is traditionally their weak point in terms of headphone design. Going from "some of the worst midrange tuning in the market" to "being arguably the best tuned midrange available in a planar right now" is a huge leap forward. For my tastes and what I gather are the needs of studio professionals and audiophiles, this is just about as good as midrange tuning gets.

Treble

Whether they're planar or dynamic, open or closed, cheap or expensive, almost every headphone out there has failed to provide a bearable treble tuning for me. EQ above 3kHz has basically been a fact of my existence in this hobby for the past 2 years.

Yet the MM-500 does what many headphones prior have failed to do: It let me enjoy listening to a headphone without EQ. As such, it's extremely hard for me to criticize this treble response, as I've only ever heard one or two other headphones that feel this tailored to my ears.

Even though it's pleasurable to listen to... I honestly think the treble is another limitation on its ability to be used for mix/mastering work.

I tried using MM-500 as a principal reference for mixing multiple tracks I have sitting on my hard drive, both with vocals and without. The treble was the most glaring problem on all of the mixes attempted with MM-500. For vocals, it hid problematic sibilance and led to me consistently not de-essing as much as I should have. It made cymbals sound smoother and less ringy than they actually were, so I spent less time attacking problematic resonances. Snare drums in particular sounded pleasantly rounded with plenty of "crack," but I didn't even notice that they had way too much sizzle.

While the MM-500 is undoubtedly going to serve as my planar tonal reference going forward, I just find it too smooth and good sounding to be usable in it's stock configuration for the task of mixing or mastering. You can "fix" those areas with EQ of course, but EQ above 5kHz is an arduous process that you have to do entirely manually (and again, you can't expect everyone to EQ).

The theme here ought to be clear by now. The ideal headphone for listening is not always the ideal headphone for mixing or mastering, and that's because the goals are fundamentally different.

Audiophile listening is chiefly concerned with pleasurable reproduction, which takes many forms. Though studies tell us "good" tends to be aligned meaningfully with people's idea of "accuracy," there are many cases to the contrary. When it comes to audiophilia, there's really no reason to turn down any idiosyncrasy that makes the sound more subjectively pleasing to the listener (whether it brings it closer to reality or not). While I do want my headphone to sound as true-to-life as possible, I acknowledge that this likely won't happen with any headphone, so settling for something reasonably accurate that doesn't make me wince is enough most times.

Mixing and mastering however, is about both production and reproduction, and the treble on MM-500 is just too likeable a reproduction for me to be critical of a track when listening.

Audio professionals need something that walks the tightrope between being orthodox enough to be representative of the masses (and thus, imperfect in predictable ways) and being good enough to not give an entirely decorrelated presentation of what the music actually sounds like. The MM-500 does very well at the latter for me, but I find it's tuning leaves some to be desired for the former.

Dynamics

Being upfront: I've never been a fan of the technical performance you get with most planar headphones. Speed, separation, staging, all tend to be things that I'd be perfectly happy losing in favor of naturalness, punchiness, and imaging coherence.

So when it comes to dynamics, I wish I had better news... but MM-500 like most Audeze planars is merely okay. This isn't an especially big, contrasty, slammy, or weighty headphone. That may be fine for most people, but it's something I find myself missing on this headphone, especially since the tuning is such a massive hit for me. Especially compared to its oft-mentioned big brother LCD-X, there is a meaningful loss of microdynamic complexity and richness that can make the MM-500 sound more truncated than many Audeze planars.

This may well have some benefits. Those who enjoy the speed, lack of sloppiness, and surplus of control that planars can have will find plenty to love here, more than even on LCD-X.

But to me it kind of sounds like trails and instrument decay are almost suffocated. Transient definition has gone beyond the realm of "pleasantly rounded" and into the territory of being slightly smudged. While this is better than the preternaturally thin presentation of something like Hifiman's Susvara, it is a little too blurred and indistinct to have enough of the precision or definition I love in other flagship favorites like Utopia.

When it comes to studio work though, the answer is more of a "Yesn't." The presentation typical of planars leaves quite a gap between what someone mixing on MM-500 is hearing, and someone listening on AirPods is hearing. However, something interesting happened when tuning compressors on snare drums in particular: I seemed to get more nuanced information on changes to the front end of the envelope as I moved around compressor settings (especially the attack) than I did on my HD800.

I feel that the MM-500 isn't terrible or great, dynamically. It's also perhaps too different from the norm to be truly informative of what most people will hear. But the effect of being able to hone in with more precision on the front ends of my transients was actually a really nice thing to have. A mixed bag for sure, dynamically... but not one I didn't expect.

Timbre

So this is again where I feel the MM-500 takes one step forward and two steps back versus its brothers and sisters (namely the LCD-4 and 5). It's not as lean and plasticky as the LCD-5s I've heard were, so it definitely outright beats LCD-5 in this respect.

I'll explain briefly to the pro audio readers what audiophiles mean when we say "timbre," because in the world of musicians/pro audio it means something different.

When audiophiles talk about timbre, we are talking about a quality of sound reproduction that includes two main things:

1) Instrument identity; both in how true to life something sounds, as well as how easily you can differentiate between different instruments. Usually analyzed through the lens of frequency response and perceived time-domain presentation, though I'd argue every other aspect of sonic analysis can be folded in here somewhat.

2) Material related character, eg. "this sounds plasticky" "there's a metallic ringiness at play here" etc.

Touching on the latter, MM-500 stands in contrast to the LCD-R I just reviewed. The MM-500, like LCD-R, has a different type of material related character, though for perhaps not the best reasons. The mix of shortened decay, slight 300Hz tubbiness, 4-5khz textural blur, and a smudged dynamic presentation all leads to the sound here being kind of... squeaky. Rubbery, even.

It just feels like textural nuance on MM-500 has had a pencil eraser taken to it and some of the eraser shavings were left behind. While I personally prefer this immensely to the cloyingly plastic or metallic presentations of other planars, I can't say it does better at all when it comes to portraying nuances of instrument identity. Things are homogenized to all sound kind of squeaky, rubbery, and stodgy.

Now, timbre has never been a strong suit of planars, so I didn't have high expectations here. I will reiterate that I do prefer this type of timbral character to basically all of the other planars I've heard... but that doesn't mean it's what' I'd call "good." It's just better, and significantly so, than the outright terrible timbre I'm used to on most other planars.

Soundstage and Imaging

This is where I feel MM-500's presentation could be a seen double-edged sword vs. the older LCD-X or the similarly new LCD-5, though I prefer to see it as a happy midpoint between the two.

The LCD-X has the longest feeling decay of the three, as well as the largest driver of the three. As such, reverb tails are more perceptible and images themselves are bigger, so overall the presentation is perhaps more "grand" and expansive.

That being said though, I always found LCD-X's stage and imaging to be one of its biggest drawbacks. For one, the front-left and front-right stage are almost non-existent. Additionally, the images are too tall such that they crowd an already poorly integrated soundstage. Images on LCD-X take up all of the space from top to bottom and occupy strange areas in the lateral space, leaving you with a feeling that you're listening to an indistinct but very imposing and close wall-of-sound.

On LCD-5, the driver is smaller and the images get shrunken as well, which is actually a good thing. The front-left and front-right stage are also brought into the fold, if anything a bit too much (LCD-5's stage is at times almost entirely front-left and front-right).

MM-500 seems to have a mix of the two. The images are thankfully smaller, and the front-left/front-right stage are more coherent, yet not the only thing present. Unlike the other two, MM-500 has a soundstage that actually makes sense and doesn't feel oppressive when you're listening to it.

As far as how it stages for studio folks... do your panning in speakers, please.

Headphones are devices of in-head localization. In my experience, any approximation or illusion a headphone portrays that is reminiscent of "speaker staging" will be rendered thoroughly useless as soon as you take them off and listen to actual speakers.

Conclusion

MM-500 is not some massive technical leap forward for Audeze, planar magnetic headphones, or headphones in general. It doesn't merit the label of "planar HD600" that people also tried to lob at LCD-5 upon its release.

But I think what Audeze's done here is arguably more important than any of that. They made a pretty damn well-rounded planar magnetic headphone.

The tuning is, and I cannot stress this enough, awesome. The dynamics are pretty much standard for the driver type, if a little more rounded/blunted and less thin (tradeoff). The timbre is somewhat odd, but still better than the most other planars both from Audeze and its competitors. The staging and imaging—while small—is coherently integrated across the front and doesn't make me feel overwhelmed by a wall of sound.

I know I nitpicked a lot, but that's what I'm supposed to do. Despite it all, I really enjoy listening to music on the MM-500. I honestly have trouble thinking of any planar that's this well rounded for my taste at any price and for that reason I'm happy to recommend it.

From the pro audio perspective, MM-500 is somewhat held back by its driver type, but make no mistake: it was always going to be that way.

People by-and-large aren't listening on planars and this is an obvious downside to any planar being used for professional work. But the two most crucial things for a pro-audio headphone to do—by my estimation—are neutrality and extension. MM-500 hits these both as well or better than any headphone on the market, so for that reason it still gets a recommendation if you want a neutral headphone for mix/mastering work.

Audeze opening themselves in earnest to a market they were already having great sales in was a good move, but I think an unfortunate side effect of MM-500 being marketed to audio professionals is that MM-500 has kind of already been ignored by a lot of audiophiles.

MM-500 really isn't the kind of headphone to wow an audiophile at a show, but as I've learned, the good stuff usually isn't. What MM-500 is however, is an incredibly easy headphone to live with. It's "a master of none," but MM-500 has done what many planars fail to do. MM-500 balances a solid tuning and competent performance in other technical aspects into a coherent package that is reasonably comfortable, looks good, and isn't unreasonably expensive. That's... actually not super common in the headphone hobby.

If the choice is between MM-500 and another headphone that specializes in one thing at the expense of everything else (which is most expensive headphones, to be clear) I will enthusiastically choose the jack of all trades every single time.