The Koss QZ900 are comfortable mid-tier heaphones that deliver decent noise isolation and passable but bass-heavy audio reproduction. However, the all-plastic build and lack of adequate in-line controls make them feel cheap and less durable.
The QZ900 do well as everyday casual headphones. They lack a little isolation for loud environments but perform decently well under other test cases. Sadly their sound quality is not the best.
Subpar for critical listening. These headphones have a closed sound and a skewed, bass-heavy audio reproduction. This makes them sound too dark for critical listening.
Not ideal for commuting. They have below-average noise isolation and won't be able to cancel the loud ambient noise of a busy commute.
Below-average for sports use. They're lightweight, comfortable and stable. However, they're a bit bulky and don't have a decent control scheme.
Below-average for office use. The weak noise isolation does not cancel the ambient noise of busy office, but they don leak much.
Mediocre at best for home theater use. They have negligible latency since they're wired headphones. However, their poorly balanced sound and limited range won't be ideal for watching movies.
The QZ900 look surprisingly good, if a little cheap because of the all-plastic esthetic. The two-tone silver and black ear cups are oval and cushioned with a soft, black padding. The headband is also coated with black padding and the frame is a dense black plastic which works with the overall esthetic but looks cheap.
The QZ900s are surprisingly comfortable. The plush, well-padded ear cups mold well around the ears and the headband does not apply too much pressure. The all-plastic design also keeps them light, which adds to the comfort. The ear cups are a little small, however, so depending on the ear size, they might not be as comfortable for everyone.
Button layout is simple but inefficient at giving you any sense of control over your music. There's one noise cancelling switch on the the right ear cup, which is easy to use, but the provided in-line audio cable has only volume controls and no play/stop button, which is disappointing.
The Koss QZ900 deliver a stable listening experience. The broad headband and lightweight earcups prevent the headphones from swaying while running or jumping. They stay in place during casual listening sessions and are tight enough not to slip off your ears during high-intensity activities.
The Koss QZ900 have a more compact frame than some the over-ear headphones, which makes them, moderately portable. They will fit in relatively small bags or handbags. However, their earcups do not lay flat or fold up to take less space. They're too cumbersome to carry around on your person and will not fit into any pockets, even larger jacket pockets.
Comes with a soft case that will protect the headphones from scratches and minor falls. However, it will not shield the headphones from water damage, and the fabric that covers the case feels a bit loose and susceptible to wear and tear.
The plastic build quality does not seem the most durable and feels a little cheap. The ear cups and headband are well padded and the headphones don't creak as much as you would expect an all-plastic design to. However, the lack of any metal joints or frame affects the sturdiness and the overall build quality of the QZ900.
Comes with a 1/8" TRS-TRS with volume but no call/music control.
Great passive noise isolation starting at 500Hz and up to 6KHz, where it reaches -40dB of attenuation. The active noise-cancelling however, is not as effective. Adding just over 10dB of reduction from 40Hz to 200Hz.
Very good leakage performance, considering these are over-ear headphones. You shouldn't worry about leakage when listening to these headphones at moderate volumes.