- Table of Contents
- Intro
- Design
- Sound
- Isolation
- Active Features
- In the box
- Conclusion
- Discussions
Reviewed on Feb 29, 2016
By Sam Vafaei
, Marc Henney
Koss QZ900
HEADPHONES REVIEW
Usage Ratings -
Version 0.9
Test Benches:
- 1.2: Winter 2018
- 1.1: Summer 2017
- 1.0: Winter 2017
- 0.9: Winter 2016
5.8
Mixed Usage
What it is:
This is the combination of the different use cases to evaluate how versatile the headphones are. Therefore an everyday headphone should be well-rounded enough to adapt to most situations and environments without significant losses in sound quality, design ergonomics or isolation.
Score components:
- 25% Commute/Travel
- 25% Office
- 25% Sports/Fitness
- 25% Critical Listening
Score distribution:
5.8
Critical Listening
What it is:
The level of audio fidelity a headphone can reproduce. Therefore a balanced and true representation of bass, mids, treble, soundstage and imaging, as well as a comfortable listening experience, is essential for critical listening.
Score distribution:
5.7
Commute/Travel
What it is:
How well the headphones handle the loud environments involved in commuting or traveling. Therefore your listening experience should be comfortable, hassle-free and as isolated from noise as possible.
Score components:
- 26% Noise Isolation
- 11% Battery
- 10% Comfort
- 10% Portability
- 10% Build Quality
- 6% Wireless
- 5% Controls
- 5% Breathability
- 4% Bass
- 4% Mid
- 4% Treble
- 4% Leakage
- 1% Total Harmonic Distortion
Score distribution:
5.9
Sports/Fitness
What it is:
How well-adapted the headphones are, to use while doing sports or strenuous exercise. Therefore the headphones should not be too cumbersome and deliver a stable and comfortable listening experience.
Score components:
- 23% Stability
- 22% Portability
- 9% Breathability
- 8% Comfort
- 8% Wireless
- 6% Controls
- 5% Noise Isolation
- 4% Battery
- 4% Bass
- 4% Leakage
- 3% Mid
- 3% Treble
- 1% Total Harmonic Distortion
Score distribution:
5.9
Office
What it is:
How well the headphones can deliver a comfortable and isolated listening experience in an office-like environment. They should not leak much and should block the noise of a busy office.
Score components:
Score distribution:
6.3
Home Theater
Score components:
- 27% Latency
- 19% Sound
- 18% Comfort
- 14% Wireless
- 5% Build Quality
- 5% Breathability
- 5% Battery
- 4% Noise Isolation
- 3% Leakage
Score distribution:
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.
Check Price
QZ900
SEE PRICE
Amazon.com
Design
Score components:
- 28% Comfort
- 5% Controls
- 12% Stability
- 12% Portability
- 4% Case
- 29% Build Quality
- 10% Breathability
Score distribution:
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
What it is:
Adjustability and degrees of freedom, pressure, stiffness and weight.
When it matters:
When the headphones are going to be used for long durations.
Score components:
Subjectively assigned
Score distribution:
Clamping Force
:
1.30 lbs
What it is:
The force that the headphones exert on your head, once you have them on. This is purely a measurement of the force applied, which does not take into account the earpad's surface area and the resulting pressure you will feel, on or around your ears.
When it matters:
The tighter the headphones, the more force they put on your head. This can get uncomfortable or cause pain and soreness during long listening sessions.
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
What it is:
The control scheme of the headphones, the number of functions provided, button layout and ergonomics as well as the quality of tactile feedback.
When it matters:
If you want to control volume, pause your music or make phone calls without directly interacting with your audio device.
Score components:
- 26% Ease of use
- 26% Feedback
- 16% Call/Music Control
- 16% Volume Control
- 11% Noise Canceling Control
- 5% Talk-Through
Score distribution:
7.5
Stability
What it is:
How the headphones are designed to prevent them from slipping off your ears or falling off your head.
When it matters:
If you plan on using the headphones while doing sports or other physical activities that requires a lot of movement.
Score components:
Subjectively assigned
Score distribution:
6.2
Portability
What it is:
The volume of space occupied by the headphones when folded into their most compact format.
When it matters:
If you're often on the move and need to carry your headphones in a bag, purse , or pocket.
Score components:
- 20% Volume
- 80% Stand required
Score distribution:
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
What it is:
The provided carrying options to protect your headphones when transporting them.
When it matters:
To prevent damaging your headphones, if you often carry them in your bag or pocket.
Score components:
Subjectively assigned
Score distribution:
5.5
Build Quality
What it is:
Durability, material quality, cheap/expensive feel.
When it matters:
When the headphones are going to be used by multiple users (classes/studios), by children, in tough conditions, on a daily basis, or for exercise.
Score components:
Subjectively assigned
Score distribution:
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.
Sound
What it is:
How accurately the audio is reproduced. The tests are performed with the headphones' most commonly used features enabled (noise-cancelling, wireless, etc.)
Score components:
- 21% Bass
- 20% Mid
- 19% Treble
- 5% Frequency Response Consistency
- 21% Soundstage
- 5% Imaging
- 9% Total Harmonic Distortion
Score distribution:
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
What it is:
Frequency Response from 20Hz-250Hz
When it matters:
When the material is heavy on bass frequencies, such as those of kick drums and bass guitar.
Score components:
- 90% Std. Err.
- 10% Low-Frequency Extension
Score distribution:
Std. Err.
:
6.13 dB
What it is:
The amount of deviation (weighted standard error) in bass frequency response (20Hz-250Hz) as compared to a target response that would sound perfectly balanced to most people.
When it matters:
When a balanced and neutral (reference) bass performance is desired.
Good value:
<4dB
Noticeable difference:
0.1dB
Score distribution:
Low-Frequency Extension
:
10.0 Hz
What it is:
The lowest frequency at which the frequency response reaches -3dB of the target response.
When it matters:
Shows how extended the bass is.
Good value:
<40Hz
Noticeable difference:
5Hz
Score distribution:
Low-Bass
:
7.42 dB
What it is:
The average amount of over/under-emphasis in frequency response from 20Hz-60Hz.
When it matters:
Kick drums and low frequency effects get their 'thump' from this range. Mostly felt than heard.
Good value:
+/-3dB
Noticeable difference:
0.1dB
Bass
:
5.94 dB
What it is:
The average amount of over/under-emphasis in frequency response from 60Hz-120Hz.
When it matters:
Melodic bass instruments have most of their fundamental frequencies in this range. This is where the 'body' and 'punch' of the bass sits.
Good value:
+/-3dB
Noticeable difference:
0.1dB
High-Bass
:
5.97 dB
What it is:
The average amount of over/under-emphasis in frequency response from 120Hz-250Hz.
When it matters:
Most instruments get their warmth and full-ness from this range. When over-emphasized, mixes tend to get muddy and boomy.
Good value:
+/-3dB
Noticeable difference:
0.1dB
7.4
Mid
What it is:
Frequency Response from 250Hz-2KHz
When it matters:
When the material is heavy on mid-range frequencies. This is the case for the majority of audio content.
Score components:
- 100% Std. Err.
Score distribution:
Std. Err.
:
3.47 dB
What it is:
The amount of deviation (weighted standard error) in mid frequency response (250Hz-2.5KHz) as compared to a target response that would sound perfectly balanced to most people.
When it matters:
When a balanced and neutral (reference) mid performance is desired.
Good value:
<4dB
Noticeable difference:
0.1dB
Score distribution:
Low-Mid
:
0.85 dB
What it is:
The average amount of over/under-emphasis in frequency response from 250Hz-500Hz.
When it matters:
Most instruments have their fundamentals or low harmonics in this range. Over-emphasis in this range sounds muddy and cluttered. Under-emphasis, thins out the vocals and lead instruments.
Good value:
+/-3dB
Noticeable difference:
0.1dB
Mid
:
-2.5 dB
What it is:
The average amount of over/under-emphasis in frequency response from 500Hz-1KHz.
When it matters:
This range is occupied mostly by upper harmonics. Over-emphasis sounds forward and boxy. Under-emphasis pushes instruments to the back of the mix.
Good value:
+/-3dB
Noticeable difference:
0.1dB
High-Mid
:
-0.92 dB
What it is:
The average amount of over/under-emphasis in frequency response from 1KHz-2KHz.
When it matters:
Most instruments, especially vocals, get their intensity and clarity from this range. Over-emphasis sounds honky and harsh, under-emphasis sounds weak and distant.
Good value:
+/-3dB
Noticeable difference:
0.1dB
2.7
Treble
What it is:
Frequency Response from 2KHz-20KHz
When it matters:
When the material is heavy on high-range frequencies, such as voice, cymbals, and any other material where brightness, brilliance and airiness is desired.
Score components:
- 100% Std. Err.
Score distribution:
Std. Err.
:
8.63 dB
What it is:
The amount of deviation (weighted standard error) in treble frequency response (2.5KHz-20KHz) as compared to a target response that would sound perfectly balanced to most people.
When it matters:
When a balanced and neutral (reference) treble performance is desired.
Good value:
<4dB
Noticeable difference:
0.1dB
Score distribution:
Low-Treble
:
-3.63 dB
What it is:
The average amount of over/under-emphasis in frequency response from 2KHz-5KHz.
When it matters:
Almost all instruments rely on this range for their presence, detail, and articulation. Over-emphasis can sound harsh and painful. Under-emphasis hurts the comprehensibility of vocals and lead instruments.
Good value:
+/-3dB
Noticeable difference:
0.1dB
Treble
:
-8.8 dB
What it is:
The average amount of over/under emphasis in frequency response from 5KHz-10KHz.
When it matters:
This is the sibilance range. Cymbals, vocals, and lead instruments rely on this range for brightness and presence. Over-emphasis sounds piercing and painful, under-emphasis sounds dull and lispy.
Good value:
+/-3dB
Noticeable difference:
0.1dB
High-Treble
:
-8.29 dB
What it is:
The average amount of over/under-emphasis in frequency response from 10KHz-20KHz.
When it matters:
This range gives brilliance and airiness to the sound. Over-emphasis sounds hissy, under-emphasis sounds closed-up and lifeless.
Good value:
+/-3dB
Noticeable difference:
0.1dB
8.8
Total Harmonic Distortion
What it is:
The subtle, unwanted frequencies (harmonics) produced alongside the intended frequencies.
When it matters:
When clean and pure sound reproduction is desired, though its effect is not as noticable as frequency response.
Score components:
- 50% Weighted THD @ 90
- 50% Weighted THD @ 100
Score distribution:
Weighted THD @ 90
:
0.177
What it is:
The overall amount of harmonic distortion measured at 90dB SPL. To make the score more perceptually relevant, more weight is given to the higher frequencies.
When it matters:
How pure the sound is at moderate listening levels.
Good value:
<0.100
Noticeable difference:
0.1
Score distribution:
Weighted THD @ 100
:
0.421
What it is:
The overall amount of harmonic distortion measured at 100dB SPL. To make the score more perceptually relevant, more weight is given to the higher frequencies.
When it matters:
How pure the sound is at loud listening levels.
Good value:
<0.300
Noticeable difference:
0.1
Score distribution:
Isolation
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
What it is:
How much outside noise is blocked out by putting the headphones on.
When it matters:
If the headphones are going to be used in a noisy envinronment (airplane, subway, etc.)
Score components:
- 29% Bass
- 29% Mid
- 28% Treble
- 14% Self-Noise
Score distribution:
Overall Attenuation
:
-17.81 dB
What it is:
The overall amount of environmental noise reduction in dB.
When it matters:
In loud envinronments like planes, trains, offices, etc.
Good value:
<-20dB
Noticeable difference:
1dB
Bass
:
-9.48 dB
What it is:
The overall amount of noise isolation in the bass range (20Hz-250Hz).
When it matters:
When the outside noise is bass-heavy, like in airplanes.
Good value:
<-15dB
Noticeable difference:
1dB
Score distribution:
Mid
:
-10.98 dB
What it is:
The overall amount of noise isolation in the mid-range (250Hz-2.5KHz).
When it matters:
When the environment's noise is mid-heavy, like in an office.
Good value:
<-15dB
Noticeable difference:
1dB
Score distribution:
Treble
:
-35.14 dB
What it is:
The overall amount of noise isolation in the treble range (2.5KHz-20KHz).
When it matters:
When the environment's noise is treble-heavy. Although uncommon, areas with sharp sounds fall under this category.
Good value:
<-30dB
Noticeable difference:
1dB
Score distribution:
Self-Noise
:
18.42 dB
What it is:
The amount of noise created by the active electronics of the headphones (if applicable), measured from 300Hz-20KHz. Applies mostly to wireless and noise-cancelling headphones.
When it matters:
If too loud, it could become distracting when listening to quiet material like podcasts and audiobooks.
Good value:
<16dB
Noticeable difference:
1dB
Score distribution:
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
What it is:
The amount of sound bleeding out of the headphones.
When it matters:
When the listener doesn't want people around them (in office, recording studio, etc.) to hear what is being listened to.
Score components:
Score distribution:
Overall Leakage @ 1ft
:
33.58 dB
What it is:
The amount of sound leakage heard 1 foot away from the user, while the user is listening to a 100dB SPL signal.
When it matters:
When you don't want people hear what you are listening to.
Good value:
<35dB
Noticeable difference:
1dB
Score distribution:
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
What it is:
Headphones with active components that require a battery. This includes noise cancelling and wireless headphones that actively reduce noise or transmit audio via a wireless connection.
When it matters:
How suitable the power and wireless specifications of an active headphone will be, depending on your listening habits. The range and/or discharge time of the active headphone you select will be important if you're often on the move or have long uninterrupted listening sessions.
Score components:
- 30% Wireless
- 13% Latency
- 52% Battery
- 5% App Support
Score distribution:
No active features.
0
Wireless
What it is:
Headphones that offer a cable-free listening experience over a wireless network, typically via Bluetooth or radio frequency.
When it matters:
If you don't want to be limited by the length of an audio cable. This means having the freedom to move around in your home or office with a much greater range than an audio cable could provide, especially, if the Bluetooth source is heavy or difficult to carry.
Score components:
- 72% Obstructed Range
- 21% Line of Sight Range
- 7% NFC
Score distribution:
Type
:
N/A
What it is:
The type and version of the wireless network, the headphones use to connect to the audio source. This could either be Bluetooth or radio frequency.
When it matters:
The Bluetooth version will determine how compatible the headphones are with your Bluetooth enabled devices. Typically, newer Bluetooth versions are backward compatible with older ones but may lack the additional features that more recent Bluetooth protocols provide.
Obstructed Range
:
N/A
What it is:
The range that the wireless headphones can reach before dropping any audio when the Bluetooth source was placed in another room.
When it matters:
If you can't or prefer not to carry your Bluetooth source on you, while listening to your audio in an indoor environment. Although, the obstructed wireless range will slightly depend on your home or office layout.
Good value:
35ft or more
Noticeable difference:
5ft
Score distribution:
Line of Sight Range
:
N/A
What it is:
The range that the wireless headphones can reach before dropping any audio when in direct line of sight of the Bluetooth device.
When it matters:
If you can't or prefer not to carry your Bluetooth source on you, while listening to your audio in a large and open environment.
Good value:
170ft or more
Noticeable difference:
10ft
Score distribution:
NFC
:
No
What it is:
Near Field Communication technology that allows you to quickly, pair your headphones with your Bluetooth and NFC-enabled device.
When it matters:
This makes pairing with an NFC-enabled device a lot easier than the typical and often tedious hold-to-pair procedure that most wireless headphones have.
Base Latency
:
0 ms
What it is:
The latency for the default sub-band coding of most Bluetooth headphones.
When it matters:
When watching videos a high latency can cause sync issues between the images you see and the audio you hear.
Good value:
75ms or less
Noticeable difference:
15ms
Score distribution:
aptX Latency
:
N/A
What it is:
An audio coding algorithm (Codec) that improves bit rate efficiency. It reduces latency and improves sound quality over Bluetooth.
When it matters:
For better sound quality if your often streaming music over Bluetooth. Also it slightly improves latency when watching videos with wireless headphones.
Good value:
130ms or less
Noticeable difference:
15ms
Score distribution:
aptX(LL) Latency
:
N/A
What it is:
Low latency variation of aptX that significantly reduces sync issues between video and sound when using Bluetooth headphones.
When it matters:
When watching videos or gaming latency is a lot more noticeable than just listening to music.
Good value:
50ms or less
Noticeable difference:
5ms
Score distribution:
N/A
Battery
What it is:
The power source of your headphones. All headphones with active features have a battery that will deplete over time.
When it matters:
To continue using the active features of your headphones. Some models lose features or switch off completely when the battery is drained, which limits what you can do with them until the next charge.
Score components:
- 60% Battery Life
- 25% Charge Time
- 10% Auto-off
- 5% Audio while charging
Score distribution:
Battery Life
:
N/A
What it is:
The amount of time it takes for a headphones' battery to be completely drained. Battery life will vary depending on the active features used and volume level.
When it matters:
For active headphones that connect wirelessly, have noise cancellation or other audio-enhancing features, that cease to work once the battery is dead.
Good value:
>10hrs
Noticeable difference:
0.5hrs
Score distribution:
0
App Support
What it is:
The additional app provided to enhance your listening experience. They typically deliver a set of practical features that give you more control over the sound, noise cancelling and effects that the headphones produce.
When it matters:
An app with a lot of features allows you to customize your listening experience to suit your taste and preferences. For example, additions like an equalizer can give you more bass or treble and room effects can simulate a bigger Soundstage in closed back headphones.
Score components:
Subjectively assigned
Score distribution:
No compatible app.
In the box
- Koss Quiet Zone 900 Headphones
- Audio cable
- Carrying case
- Manual
Conclusion
SEE PRICE
Amazon.com
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.
