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Say goodbye to distractions and hello to your music

Let background noise melt away, so you can be alone with your music. The Koss QZ900 headphones feature active noise cancelation circuitry to electronically neutralize external distractions. Your tunes will sound clearer and bolder when they don't have to compete with annoying office noise or plane engine hum. The QZ900 delivers impressive bass response, for deep grooves that will get you through those long flights or endless hours at the office.

Listen anytime with passive mode

Noise-canceling headphones are terrific...until the battery dies. That's why you'll appreciate the QZ900's passive listening mode. If your battery runs low, just switch off the noise-canceling circuitry and you're free to listen endlessly in passive mode. The QZ900's closed-back design provides excellent noise isolation even without the noise cancelation activated, so you can choose when you need that extra noise-blocking power.

Designed for the long haul

Because Koss knows you'll want to listen to the QZ900 for long periods, they built them for long-lasting comfort. The soft foam headband is cushioned yet secure, and the padded earcups make these headphones disappear just like outside noise. Fold them up and stash them in the included travel case, so they're always ready to accompany you on your next trip, near or far.

Product Highlights:

  • active noise-cancelation for blocking out external noise
  • listen in active or passive mode
  • in-line volume control
  • 4-foot detachable miniplug cable
  • fold-up design for easy storage and portability
  • carrying case
  • 1 "AAA" battery required for active noise-canceling (up to 50 hours)
  • frequency response: 20-20,000 Hz
  • sensitivity: 100 dB
  • impedance: 32 ohms
  • warranty: lifetime
  • Our 60-day money-back guarantee

Koss QZ900 Reviews

Average Customer Review:

1 Review

Koss QZ900 Noise-Cancelling Headphones

Written by: AKBrownBear from Eagle River , AK on April 24, 2013

Crutchfield Customer Review (What's this?)

  • "Coolness Factor"
  • Build Quality
  • Comfort
  • Noise Reduction
  • Sound Quality

I purchased them for use in my tractor and excavator. Noise canceling is the primary reason for using headphones,. I am 67 still have reasonably good hearing,

I retuned the headphones to Crutchfield. The noise canceling was minimal and they had a noticeable hiss. The Crutchfield support team went on line to a few product review sources and found ratings all over the place. It appears from the "diversity" of the reviews that Koss' quality control is poor. With that track record, I went to Bose for replacement,

It is too bad because I liked the fit better than the Bose units I traded up to. Crutchfield's support team is awesome! I have never been treated better when I have had to return something and got really good advice from the team. The Bose noise canceling ability is fantastic.

Pros: Rugged design and construction. Good over-ear muffs. Good fit. Lifetime warranty.

Cons: They didn't work. Minimal noise canceling ability; noticeable hiss.

Hands-on research

What's in the box?

Download owner's manual

  • Noise-canceling headphones
  • 4' Straight cable with in-line volume control (3.5mm straight plugs on each end)
  • Zippered semi-hard storage case
  • Manual
  • Battery Replacement instructions

Features and Specs

Fit Style Over-the-ear
Earcup Type Closed
Noise-canceling Yes
Bluetooth No
Frequency Response 20-20k Hz
Sensitivity 100 dB
Impedance 32 Ohms
Weight 7.7 ounces
Cord Length 48"
Airline Adapter Included No
iPod Control No
Volume Control Yes
Built-in Microphone No
Parts Warranty Lifetime
Labor Warranty Lifetime

Product Research


Overview: The Koss QZ900 full-size headphones are equipped with battery-powered Active Noise Cancellation circuitry to shut out external noise, so all you hear is your music. The headphones comes with a detachable cord and a stylish zippered storage case.

Active Noise Cancellation: The QZ900's Active Noise Cancellation (ANC) is a special noise-canceling circuit that introduces sound waves from the outside, that are 180° out of phase with the incoming signals. The external noise is canceled out, so all you hear is your audio source. Low frequency sounds from airplanes, lawn mowers, and fans are dramatically reduced. With distracting noises eliminated, you can lower the volume of your electronics for better sound quality and less distortion. The ANC is powered by a single "AAA" battery (not included), which provides approximately 50 hours of active noise cancellation.

Detachable Cord: The headphones have a 4' detachable cable that plugs into the left earcup. It has an in-line volume control and 3.5mm plugs on each end. You can detach the cable and still enjoy passive or active noise cancellation.

Warranty: The RUK50s are covered by the Koss Stereophones Limited Lifetime Warranty.


  • Frequency Response: 20Hz-20kHz
  • Sensitivity (dB/1mW): 100dB
  • Nominal Impedance: 32 ohms

Our Product Research Team

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