Build Quality and Design
For the price it is nearly impossible to complain about the build quality of these headphones. The fact is that the are a solidly constructed studio monitor inspired headphone designed to do the hard miles. Overall the build is plastic but its the good quality stuff so we found they were relatively devoid of creaks and cracks like headphones with cheaper materials.
The inclusion of a metal headband slider is very welcome as that is one of the main points of failure on a lot of headphones and bonus points are awarded for its presence. Everything feels hard wearing and robust and like it will be capable of lasting a long time.
What I didn’t like about the design was that the earcups swivel only to adjust to your head shape and not the full 90 degrees that would allow you to lay them flat. They also do not have the ability to fold up which will ultimately make them harder to travel with.
Another point to mention is that unlike their big brothers the headphone cable is also fixed and not user replaceable like I would normally like to see.
Style wise it really comes down to user preference. I like the studio inspired monitor look and they are very similar looking to the popular ATH-M50x which is a good thing. For others though I would get if you wanted to opt for a more fashion forward looking headphone.
Comfort and Isolation
The ATH-M20x are neither the most comfortable headphones in the world or the best isolating. That said they aren’t exactly bad either. The do offer a decent amount of ambient noise reduction but it isn’t on a par with other more expense headphones of this style. The comfort is aided by the large wide earpads that offer good cushioning but the clamping pressure does cause a little discomfort after a few hours. Nothing major. The headband is nicely padded and the articulation of the earcups combined with the incremental adjustments vertically mean that almost everyone should get a good fit from them.
The sound quality can be considered very good for this price range especially if you are looking for accurate representation of notes. They are of a balanced tuning and add very little in the way of flavor to the sound. No warmth and no enhanced bass exists here. This would make them a decent shout if your are into critical listening or music production on a budget.
If you are into and aggressive / fun sound these are going to sound really flat to you again they are a more professional style of headphone and less for the consumer market.
Soundstage is lacking and they are decidedly in head listening experience although imaging and clarity were both pretty good. You can place instrumentation easily and they never feel like on frequency bleeds into another.
For the price I think the Audio Technica ATH-M20x are a good headphone if you are into music production or require a flat balanced sound reproduction. However if you are a more casual listener you are likely going to want something with a more energetic sound. Build quality is solid and they could handle day to day tasks as a studio monitor with no problems.