Audio Technica M40X Review

“Hey can you recommend me a headphone? I can reach for like…$100 but I’m not sure I want to spend that much.”

“Uhh…”

Headphones don’t have to be ridiculous. They don’t have to weigh over a pound or cost as much as a used car. They’re headphones: things people use to listen to things. Of course, there’s much, much more to that, but most people don’t need that. They don’t need different headphones that suit different moods or genres. They don’t need a “home pair and a travel pair.” They don’t need “an open pair to experience soundstage.” They just want something that works. The sub-$100 market isn’t exactly teeming with options so I often suggested people stretch a little and look for an Audio Technica M50X on sale. It has its problems, such as a narrow stage, muddy bass, dipped midrange, etc, but it’s an entertaining, consumer-friendly sound signature, has a replaceable cable, folds into a compact package, and works well enough out of a phone. It’s all most people could ever ask for. I can’t think of another headphone that has that combination of features. Many people suggest the cheaper M40X as a better alternative because it’s allegedly more neutral, but for some reason, I’d never really spent much time with it until now.

Build

The M40X doesn’t feel particularly “premium.” There is metal where it counts—the headband itself feels solid and doesn’t seem like it’ll break like other <$100 headphones, but the folding joint actuates with a slight breeze, the plastic feels cheap, and the pads are pretty thin and uncomfortable. I could barely muster an hour of use before wanting to take them off. I could also see them breaking at the yokes, where the cup is connected to the headband. On the plus side, the M40X has detachable cables with a 2.5mm connector, which is a rather common termination, albeit with a special locking mechanism, so aftermarket cables should be easy to find and they do fold up into a compact ball to throw in a bag.

Sound

As far as the sound goes…eh. It’s fine. It’s not the type of sound that I’d recommend to most people off the street. It’s a very boring sound, with a midbass boost, upper midrange dip around 3k which significantly dulls the sound, and some sharpness in the mid treble. It’s the kind of tuning that, if refined, wouldn’t be out of place in an “enthusiast” headphone, but I can’t imagine your average pop/rap/EDM listener off the street would want anything like this. It just sounds boring, and not analytical or dry-boring like a Beyerdynamic DT880 or Sennheiser HD800, just unengaging and lifeless.

Bass

I’d read from a few people that the M40X has flat bass and thus should make a great neutral studio monitor. I don’t hear flat bass. I hear a midbass bump and a noticeable subbass drop starting around 100Hz. The bass quality is about what I expect from a closed headphone in this price range. It’s not particularly clean and borders on muddy, especially on complicated passages. Versus something like the Beyerdynamic Custom One Pro Plus with one or two bass ports open, it seems a bit worse at separating bass notes and sounds a little more distorted. People probably won’t buy this headphone for its bass.

Midrange

I have a few problems with the M40X’s midrange. I hear a tiny bit of low mid dip which I don’t think I would normally notice because it doesn’t seem that great in magnitude, but the elevated midbass contrasts the somewhat thin low mid body sounds even thinner. It’s nothing like the Fostex TH900, but I’d like just a little more in that region. The upper midrange, however, is a bit more problematic. I hear a deep dip around 3kHz that makes the midrange sound rather distant, and combined with the midbass boost, sounds almost cave-like. It’s not necessarily echoic, but something does sound noticeably off. Thankfully though, I don’t hear any issues with shout. I hear a bit of a peak in around the 5kHz region, which Audio Technica seems to like to emphasize in many of its headphones to push female vocals forward. Other than the 3k dip and 5kHz peak, the midrange is actually pretty competent, especially for its price range. Tone doesn’t sound that off, which surprises me. I’d actually argue its midrange sounds more tonally accurate than a Mr. Speakers Ether C. If the dip were tuned to be a bit less severe I could even see a case for it being there as it does create a sort of spacious feeling to compensate for the fact that it’s closed and does sound closed-in.

Treble

Treble, unfortunately, seems to be a bit on the harsh side with the mid treble. I don’t hear any noticeable issues with the low treble as it seems rather balanced without sibilance issues or severe dips, but mid treble fatigues me after about an hour of listening, indicative of a rise in the 9-10kHz region. Upper treble and air seem to be very lacking, which is about par for the course with closed headphones and shouldn’t be surprising. I also hear a bit of grain, but it’s not severe enough to really complain about, especially at its price range.

Pad Alternatives

I tried a few different pads with the M40X and honestly, all of them made the M40X sound worse.

Brainwavz HM5 Angled Pleather – Midbass was muddier and upper midrange sounded more recessed. Sounds more like a cave than stock. Don’t do this.

Brainwavz HM5 Hybrid – Midbass sounds a little less strong but still elevated. Sounds duller, probably indicative of less upper midrange energy around 1-2kHz. A little better than the Pleather pads but it sounds less coherent to me than stock pads and more mid treble. There’s a comfort boost but the more boring sound isn’t worth the tradeoff to me.

ZMF Cowhide – Weird. Strongest subbass of the group, and midbass seems equally strong as stock pads but I hear some thinness in the upper bass that makes the transition from upper bass to low mid sound slightly disjointed. I hear some extra thickness to the low midrange which is one of my complaints with the stock pads, but the disjoint prevents me from really enjoying that and instead I focus on the disjoint. Sounds duller overall too, kind of like with the Hybrid pads. Less low treble too. I don’t really like it. Sounds more like a cave than the Pleather but the subbass makes it more of a fun listen.

ZMF Ori – I laughed a bit when I heard this. It reminded me a lot of the Fostex TH900. Not in a good way either. The low mids/upper bass seemed to be severely dipped, and 3k was much more dipped than stock. Try this for a laugh if you have Ori pads but otherwise don’t do this.

ZMF Pleather – Same weird transition problem as the Cowhide, but more severe. Otherwise I actually didn’t hear too much of a difference between this and stock other than I believe less 5kHz.

So far, I think the best pads for the M40X are, unfortunately, the stock pads. The other pads have too many compromises to the sound to recommend them. If I had to recommend a different pads, I’d begrudgingly recommend the HM5 Hybrids, but I wouldn’t be happy about it.

Measurements

I’ve been shying away from posting measurements of lately because I’ve found myself really realizing the limitations of my flat plate coupler. I’m getting more and more measurements off from what I hear and rather than mislead people with bad data, I’ve just opted not to post new measurements until/if I have a better system. But for the sake of a laugh and since I already took measurements with all the pads, I’ll post the measurements I took.

I’ve had a lot of problems with my measurements system with closed headphones and bass. The M40X does not have a 10dB boost of midbass. It’s closer to maybe 3dB. Also, my rig seems to have problems with 9-10kHz being underrated, which I definitely see in this measurement, as I hear much more 10k than measured.

The following pads are labeled in the graph. Blue is stock, yellow is with the internal foam that comes with stock pads, green is without.

Brainwavz HM5 Angled Pleather:

As shown, I actually did hear less upper midrange.

Brainwavz HM5 Hybrid:

Funnily enough, yellow is closest to the levels of bass I heard with stock pads.

ZMF Cowhide:

ZMF Ori:

For reference, here is my Fostex TH900 measurements:

Look familiar?

ZMF Pleather:

Conclusion

The main question people are probably wondering is, “M50X or M40X?” I can’t definitively pick a universal side, but I don’t think my prior recommendation will change. The M40X may be a better “audiophile” headphone, but most people aren’t looking for that. They’re looking for a headphone that’ll work with a variety of music and the M40X’s sound signature just isn’t as consumer-friendly as the M50X. Most people probably won’t notice the M50X’s more congested sound as an issue and instead view its more exciting, bassy and trebly presentation as a positive. And that’s fine. But for most people reading this review, the M40X is actually a pretty decent headphone and probably a good choice for someone on a budget that thinks the M50X is too colored. It’s very bland, unimpressive, unexciting, whatever, but I’m surprised how little it does wrong considering its price point. Of course, it doesn’t really do anything well but it’s safe. And to me, “safe” makes more sense than what most of the $500+ headphones are doing.