Reviewed on Feb 29, 2016


Usage Ratings - Version 0.9
Mixed Usage
Critical Listening
Home Theater
Type : Over-ear
Enclosure : Closed-Back
Wireless : No
Noise-Cancelling : Yes
Mic : No
Transducer : Dynamic

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.

Test Results
Design 6.0
Sound 5.8
Isolation 7.1
Active Features 2.7
  • Lightweight and comfortable.
  • Great seal, leaks very little sound.
  • Poor in-line control options.
  • All plastic build, feels cheap.
  • Bass-heavy audio reproduction.

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The QZ900 are a comfortable set of headphones that feel a little cheap and provide very little control over your audio. Button layout is virtually non-existent, only offering volume controls and the all-plastic design does not seem sturdy or durable. On the upside, the well-padded earcups are soft and comfortable, although they might be a little small for larger ears.


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.

6.0 Comfort
Weight : 0.50 lbs
Clamping Force
1.30 lbs

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.

4.7 Controls
Ease of use : Mediocre
Feedback : Mediocre
Call/Music Control : No
Volume Control : Yes
Noise Canceling Control : No
Talk-Through : No
Additional Buttons : No

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.

7.5 Stability

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.

6.2 Portability
L : 7.48 "
W : 6.50 "
H : 1.77 "
Volume : 86.02 Cu. Inches
Stand required : N/A

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.

6.5 Case
Type : Soft case
L : 4.72 "
W : 6.30 "
H : 3.35 "
Volume : 99.66 Cu. Inches

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.

5.5 Build Quality

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.

Detachable : Yes
Length : 3.97 ft
Connection : 1/8" TRS

Comes with a 1/8" TRS-TRS with volume but no call/music control.



The Koss QZ900 are a poor sounding pair of closed-back over-ear headphones. They have a sub-par bass, a decent mid-range, and a poor treble reproduction. Additionally, their bass is excessively heavy and boomy, their mid-range is slightly uneven, and their treble is significantly lacking. On the plus side, they don't produce a lot of distortion.

5.9 Bass
Std. Err.
6.13 dB
Low-Frequency Extension
10.0 Hz
7.42 dB
5.94 dB
5.97 dB

7.4 Mid
Std. Err.
3.47 dB
0.85 dB
-2.5 dB
-0.92 dB

2.7 Treble
Std. Err.
8.63 dB
-3.63 dB
-8.8 dB
-8.29 dB

8.8 Total Harmonic Distortion
Weighted THD @ 90
Weighted THD @ 100



The QZ900 are decent noise cancelling headphones. The earcups are well-padded and deliver a good seal that leaks very little sound, and the active noise cancelling does a decent job of nullifying ambient noise. They won't cancel all the ambient noise from your daily commute but they work well enough to not disappoint under noisy conditions.

6.6 Noise Isolation
Overall Attenuation
-17.81 dB
-9.48 dB
-10.98 dB
-35.14 dB
18.42 dB

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.

8.1 Leakage
Overall Leakage @ 1ft
33.58 dB

Very good leakage performance, considering these are over-ear headphones. You shouldn't worry about leakage when listening to these headphones at moderate volumes.


Active Features

No active features.

0 Wireless
Obstructed Range
Line of Sight Range

10 Latency
Base Latency
0 ms
aptX Latency
aptX(LL) Latency

N/A Battery
Battery Life

0 App Support

No compatible app.

In the box

  • Koss Quiet Zone 900 Headphones
  • Audio cable
  • Carrying case
  • Manual

5.8 Mixed Usage

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.

5.8 Critical Listening

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.

5.7 Commute/Travel

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.

5.9 Sports/Fitness

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.

5.9 Office

Below-average for office use. The weak noise isolation does not cancel the ambient noise of busy office, but they don leak much.

6.3 Home Theater

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.

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