Headphone Reviews

What's the difference?
Before we forge ahead with a description of the new ATH-M50x, I'd like to comment about the old M50. From my point of view, historically, the ATH-M50s primary full-size, sealed, mid-price competitors were: the Beyer DT250-250; Sennheiser HD 280Pro; and the Shure SRH440 and SRH880. All of them are good for the price, but all had some problem or other that disturbed me. The DT250-250 might be the best of the lot, but it's bass is a bit thin, and driver mismatches seem common. The HD 280Pro sounds a bit boxy, and the two Shures suffer from a lack of bass extension and a bit of treble bite. The old ATH-M50 fit right in with that group being good overall, but also suffering from a somewhat uneven response and slightly harsh treble.

As you can see from the frequency response plots of the ATH-M50 and ATH-M50x above, the newer model has about 3dB more bass response, and the peak at 10kHz is substantially reduced. The treble brightness of the old headphone can also be seen in the 300Hz square wave responses (at right). It appears the new M50x has a leading edge spike lower in level and closer to what I'd consider appropriate, and the amount of subsequent noise seems reduced at least by half. I'd consider these measured improvements moderate, yet well focussed on the weaknesses of the older headphone.

I have read in threads numerous times that people have received word from Audio Technica that the new ATH-M50x headphones are fundamentally unchanged acoustically relative to the older M50. I did follow up on this and did hear back from Gary Boss, the U.S. Marketing Director, and he too claim there should be no differences the effect the sound of these cans. After listening myself, reading the threads on Head-Fi, and talking to a couple of folks I know who's ears I trust, I've got to believe there's something different in the new cans. So I took them apart for a look inside.

In the above photo of the M50 and M50x disassembled, you can see that, from a cursory look, they appear much the same. I can tell you that I looked at everything i could get to and they appear to be identical, and I was very happy to see a substantial amount of damping material in there. I wish more makers would do that. The only difference I observed between the two models is that the driver baffle plate and capsule housing of the M50 had a mold mark that read "1", and the M50x had mold marks that read "2". However, the small circular drive cap that holds the ring of damping material on the M50x a mold mark of "1", while the M50 said "2"—the exact opposite of the other mold marks. My assumption at this point is that the mold marks identify the mold being used and there's likely at least two sets of molds. The point is, I saw no remarkable differences between the two headphones.

I did see a difference in the pads of the two models: The M50x had softer pad covers, and the open-cell foam on the newer model seemed softer and had a little more dense cellular structure. Also, it looks like the new pads have slightly smaller vent holes. I did switch the old pads to the new M50x and measured the cans. Very little difference was observed, but the new pads were a bit less noisy, and the old pads did create a fairly deep notch at around 12kHz. (Measurement .pdf for M50x and M50x with old pads.) So, some differences in the pads were observed, but that alone does not account for the measured differences between the old and new models.

At this point I can say nothing further to account for the perceived improvement of sound on the M50x, and there's probably a headphone engineer in Japan with a wry smile on his face.

ATH-M50x Sound Quality
The Audio Technica ATH-M50x does tend to follow the Harman target response curve to a first approximation, I would call it a mildly warm and fairly well balanced sound, with a slightly withdrawn mid-range. Response is a bit uneven, and these cans lack the sense of refinement one would hear from the NAD VISO HP50 or Focal Spirit Professional. None the less, these are a very good sounding headphones at this price.

Bass is fairly well extended and tight, though can become a little bloomy in the upper-bass to mids transition. Mid-range is a bit recessed centered at 300Hz causing a slight lack of body. That coupled with a mild, broad emphasis in the upper-mids/low-treble and you get vocals that lack a little organic weight, and an overall presentation that sounds slightly hard. Treble response, it seems to me, is quite good and delivers plenty of clarity and sparkle with very, very little problem, if any. It seemed, likely due to the clean treble response, that the imaging is a bit better than the older model, and well above average in this category. The dynamics are very good...in fact, because of the slightly assertive EQ of these cans, they could get a little too punchy sounding at times.

I have to say though that any flaws in the M50x only became readily apparent in comparison with much better headphones. When I acclimated to the ATH-M50x for long listening sessions, it was a wonderfully pleasing experience. The sound quality of the ATH-M50x is superb for a sealed headphone in this price range.

Summary
The Audio Technica ATH-M50x is the latest revision of a legendary headphone, and with this iteration I feel their position in the pantheon of all-time great headphones is permanently secure. Overall tonal balance is quite good, bass is tight and well extended, mids are slightly withdrawn, and the treble is lively yet free from harshness. While these cans lack the sense of refinement of some headphones of this type in higher price brackets, the overall good performance puts them right at the top of their price/type.

Coupled with the good sound, the M50x's comfort, isolation, accessories, and ability to be driven to satisfying levels from portable players makes this a great headphone for students, neophyte enthusiasts, amateur recordists, and audio professional applications where exquisite performance is not required.

The older ATH-M50 has been on the Wall of Fame for quite a while now, and the M50x will be going up on the Wall replacing it's older sibling. This is an absolutely great headphone for the price; I'm very grateful to Audio Technica for lavishing some love on the M50 to refresh it. I'm sure it will remain on the WoF for some time to come, and will remain in the hearts of headphone enthusiasts for much, much longer. Highly recommended.

Video

Resources
Audio Technica home page and ATH-M50x product page.
Audio Technica M-Series micro-site.
Head-Fi reviews here, thread here.