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Audio Technica ATH-M40

Studio Headphones By Paul White
Published December 1996

These high‑quality headphones have been redesigned to make them more suitable for studio use. Paul White listens in.

It's some time now since I reviewed Audio Technica headphones. I do recall, though, that I was very impressed by their sound quality, but less convinced that they would survive studio use. My two main concerns were that the capsules were not field‑replaceable, and that the cable was fixed rather than plug‑in. This new generation of headphones has been redesigned so that damaged capsules can be replaced in the field without needing any specialist tools, but the fixed lead remains. Admittedly, it features a strain‑relief system, but in the studio, it's all too easy to tread on a lead such as this, and it would be rather safer if it plugged into the main body of the phones, instead of being fixed.

Design & Construction

The ATH‑M40s are enclosed phones which sit on top of the ears, rather than enveloping them completely, as some designs do. A small bass port is evident on the outside of the phone. Inside, the Neodymium‑driven capsules have a very wide (5Hz‑28kHz) frequency response, though the spec fails to show how much deviation can be expected within that range. The voice coil uses copper‑clad aluminium wire, to combine lightness with good electrical conductivity, and the overall driver diameter is 40mm. With an impedance of 60 ohms, the phones can handle up to 1.6W of power, and in practice, there's plenty of clean level available. The sensitivity is quoted as 100dB, but in the absence of any reference power level, this doesn't really mean anything at all to me.

Weighing just 250g without the 3.4m cable, the phones are exceptionally comfortable and have a generously‑padded, adjustable headband. The earpads are made from the same leather‑like, soft synthetic material used by many other headphone manufacturers, and sit on the ears quite snugly, without exerting undue pressure. To facilitate one‑ear monitoring, the right earpiece can swivel through 180 degrees.


The traditional problem with enclosed phones is that while they are capable of far greater levels of bass than most open phones, they can sound a little boxy or coloured. In recent years, there have been a number of welcome exceptions to this rule, and I'm glad to say that the ATH‑M40s are one. Indeed, the sound is very similar to that produced by my Beyer DT250s, which surprised me with their clarity and accuracy when I first tried them.

In listening tests, the difference between monitoring via the ATH‑M40s and a pair of high‑quality, medium‑sized loudspeakers was astonishingly small, though the stereo imaging perceived using headphones is always different to the same material auditioned over speakers. There also tends to be a difference in bass response depending on the physiology of the listener's outer ear and, to some extent, on how snugly the phones are fitted, which means that it is unwise to rely solely on headphones when mixing, no matter how good they are. However, working with phones this good means that you can do a lot of your mixing work on them and then just do the occasional check on speakers to confirm that the bass end is doing what you think it should. In a home studio situation where noise is an issue, this can be a tremendous help.


Audio Technica have produced a very accurate‑sounding, enclosed headphone capable of more than enough sound level for serious monitoring or mixing work. Because these phones are enclosed, not only do you get a very solid bass end, you also get very little sound leakage — an important consideration when recording or overdubbing vocals or acoustic instruments. In the project studio, the ATH‑M40s should meet all headphone needs both sides of the glass; my only remaining reservation is the lack of a plug‑in lead. Even then, I guess it would be easy enough to fit a small in‑line stereo plug and socket into the lead, close to the headphones, if you felt very strongly about it. In a nutshell, though, these are some of the better‑sounding enclosed phones on the market.

Drum 'N' Bass

For the benefit of drummers and bass players, Audio Technica have produced a version of these phones, the ATH‑D40s, with an artificial lift at the bass end to create a more powerful sound. In all other physical respects, the phones are identical to the ATH‑M40s (and they retail for the same price), but the bass boost obviously makes them unsuitable for accurate mixing. However, for those recording loud instruments with a lot of bottom end, the D40s could be very useful for hearing a foldback mix properly.


  • Accurate, uncoloured sound.
  • Field‑replaceable capsules.
  • Comfortable.


  • Still no unpluggable cable.


Great‑sounding headphones for performing or mixing, with none of the usual boxiness of fully‑enclosed models.