The Audio-Technica ATH-M40x are decent headphones with outstanding, studio-quality sound. They feel sturdy and are fairly comfortable but offer no control options for your audio. They also only provide passive isolation, which might not be enough to block the noise of some listeners' commutes.
Mediocre overall design. They would perform reasonably well as everyday headphones but lack a decent control scheme, and the passive isolation is a little weak.
The Audio-Technica M40X deliver a reliable bass, mid, and treble response for neutral listening. They don't have much soundstage because of their closed-back design, but their well-balanced sound will still satisfy most listeners.
Not ideal for commuting and loud noisy environments. Their passive isolation doesn't block much noise.
Not designed for sports. They're a bit too bulky and unstable to stay put during intense exercises.
Mediocre for office use. They won't block the chatter of a busy office and leak a bit too much for a quiet one.
The Audio-Technica M40X have a very understated studio design that might look a little bland for some. They have an all-black color scheme with silver highlights on the back of the oval ear cups. Their design is very similar to the ATH-M50x. They look good but offer nothing remarkable with their design.
The large ear cups of the ATH-M40x fully encompass the ears and do not apply too much pressure to the head. They also swivel, which makes them easy to adjust. They are more comfortable than the Beyerdynamic DT 770 but the padding used for the headband and ear cups is a little rigid and squeak when moving or adjusting the headphones on your head.
The ATH-M40X, like the ATH-M30X, are decently portable headphones. They are on the larger side of over-ear headphones but fold into a more compact format that will fit in a backpack or handbag but will be too large for most jacket pockets. The thick or very long audio cable is also a bit cumbersome to carry around but unlike the lower-end model of the series are detachable.
Comes with a soft fabric pouch that does not add extra bulk and protects the headphones from scratches. However, it does not protect them from falls.
The ATH-M40X feel robust and durable. They have a mostly plastic design that's dense and able to handle a fair amount of physical stress. They have a metal frame that reinforces the headband, and the ear cups feel sufficiently sturdy to withstand a few drops without damage. The joints, on the other hand, are susceptible weak points where these headphones could get damaged and may weaken over time.
The Audio-Technica M40x are decently stable on the head. They are not designed for sport, so they will easily slide off your ears while running or jumping. However, for casual listening sessions, they will stay in place even if you put them on, tilted and little further back than usual. The detachable cable is also a plus for stability, as long as you remember to unlock the cable from the ear cups.
Poor isolation. The passive isolation provided by the ear cups does a decent job of blocking treble sound. However, as the frequency lowers, so does the effectiveness of the passive isolation. Their effect below 400Hz is minimal.
Average leakage. These headphones do leak some sound, and the majority of that happens between 500Hz and 4KHz, which is rather broadband. However, the overall leakage is not too loud.
No compatible app.
The Audio-Technica ATH-M40x and the Sennheiser HD 280 Pro are both decently neutral-sounding closed-back headphones. The Audio-Technica are more comfortable, which makes them better-suited for long critical listening sessions, but they can sound quite boomy and even piercing at times. The Sennheiser have a much more neutral bass and smoother overall sound but aren’t very comfortable.
The Sony MDR-7506 are better headphones for neutral sound listening than the Audio-Technica ATH-M40x. The Sony are more consistent among various users, have a much better-balanced and more accurate sound profile, have less distortion, and leak less audio. On the other hand, the Audio-Technica have a more comfortable and stable design, have a slightly wider soundstage, and come with two different detachable audio cables.
The Audio Technica ATH-M50x are very similar to the Audio Technica M40x, but they have a slight edge over them. They feel a bit sturdier and better-built than the M40x, and their audio reproduction is slightly more accurate and neutral. Also, the M40x have elevated distortion, so they might sound a bit impure at high volumes, while the M50x will sound cleaner. Both headphones will give you great sound and are also great options for critical listening, but the M50x offer one of the best values on the market due to their great price-to-performance ratio.
The Audio-Technica ATH-M40x and the Shure SRH 400 are both closed-back, open-ear headphones with similar performances for critical listening. The Shure are more comfortable and have a slightly more even sound profile, but they lack a bit in the low-bass. The Audio-Technica, on the other hand, have an overemphasized bass, particularly in the high-bass range, which can make them sound muddier.
The Beyerdynamic DT 770 PRO are slightly better than the Audio-Technica ATH-M40x. The Beyerdynamic have a slightly more accurate overall sound signature, but some people feel like they are slightly too sharp and piercing. On the upside, they're noticeably more durable than the Audio-Technica thanks to their full-metal frame and large ear cups. If your budget allows it, go for the Beyerdynamic, unless you’re sensitive to higher frequencies.
The Audio-Technica ATH-M40x are better headphones for a neutral sound than the Audio-Technica ATH-M30x from the same lineup. The biggest difference is that the M40x is definitely more neutral in the treble range, where the M30x lack a lot of detail and brightness. The M40x also come with a nice coiled cable, but other than that, they're very similar.