The Audio-Technica ATH-AD900x headphones have an excellent, detailed, high-fidelity sound but are bogged down by the fact that the 3D wings are made of plastic. The sound signature is a bit unusual, although this is nothing that can’t be tweaked out

I would recommend these if you need an entry-level, open-back audiophile headphone with a lot of air in the treble and an overall detailed and revealing signature. I actually thought the bass was heavier than most people claimed.

I felt instantly at home when I put on the ATH-AD900X. It felt much like the original, and sounded much like the original. I heard that huge, open sound I loved before; it seemed less like listening to a headphone and more like listening to a pair of speakers in a room.

If you're looking for an open-backed set of cans to adorn your skull at home, the ATH-AD900x will do so in style, clad in backs that are reminiscent of black metal fishnets. Just keep in mind that these headphones mark a slight departure from the previous iteration, as they do not have a completely even frequency response—they underemphasize some of the higher sounds, and that may or may not fit with what you're looking for.

These remarkably clear and spacious headphones are worth serious consideration

The AD900X is a pair of polarizing headphones. Their thin mid and treble-focused sound will NOT be everyone’s cup of tea. The comfort is great but at the same time, you have to deal with the weird fit of the 3D-wings. Build quality is mainly plastic but that is why they are so light.

The ATH-AD900X’s are not bass-heavy, nor overly warm, but instead favor a neutral, detailed, and airy sound with wonderful soundstaging.