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Koss QZ99: The Quintessential On-Ear Headphone

Initially designed for racing radio scanner and metal detector users, the Koss QZ99 Passive Noise Reduction Headphones feature superior isolating capabilities and secure over-the-head headband design.

The closed Pneumalite™ ear cushions and extra-secure headband create a tight seal around the ear eliminating all ambient noise and are built to withstand the rigors of indoor and outdoor use.

Key Features

  • Passive Noise Reduction Headphones.Connectivity Technology: Wired
  • Neodymium Magnet Structures Deliver Outstanding Clarity & Definition
  • Closed Pneumalite(Tm) Ear Cushions & Extra Secure Headband Seal Ears, Eliminate All Ambient Noise
  • Volume Control On Ear Cup Allows Easy Level Adjustment
  • Stereo/Mono Switch Extends User Flexibility
  • Passive noise reduction stereophone system isolates listener from ambient sounds
  • Volume control on earcup for easy level adjustment
  • Ideal for use with racing scanners and metal detectors
  • Stereo/mono switch for added flexibility
  • Single-entry, 8-foot coiled cord

Sound Quality

The QZ99 delivers well-balanced audio with sparkling highs, lively mids, and robust low end. The bass packs a punchy kick on tracks like hip-hop and EDM but avoids muddiness.

From Arcade Fire to John Coltrane, the 40mm drivers handle a wide range of genres with aplomb. The soundstage is intimate but has enough space to pick out instrumental separation.

While not completely neutral, the fun sound signature still retains enough accuracy for critical listening. The QZ99 outperforms its small price tag.


The steel headband feels durable while keeping the weight down. The earcups swivel vertically and fold inward to fit into the included carrying pouch. This makes the QZ99 ideal for travel and commuting.

The padded ear cushions are comfortable but may feel snug for some. The on-ear fit can cause fatigue over multi-hour listening marathons.

Customer review

When I was first looking for headphones, I was running through all the ways I could block out the insanely loud (and incredibly distasteful) music that my dorm roommate was playing at all hours of the day. My first venture was through BOSE’s collection of noise-cancelling headphones, which easily ran over several hundred dollars. Being a college student, I didn’t have much money to spare, and I opted for the Koss QZ-99, which was only $41 off Amazon–and included free shipping for Amazon Prime customers.

So far, the sound quality is only mediocre at best–the bass is almost nonexistent, but the sound comes in with very little disruption from the outside. The headphones are big, bulky, somewhat heavy, and *very* tight on the ears, especially for big-headed people like me. The headphones are decently comfortable because they fit snugly around the ear, rather than sitting on top of the ear and squishing all of your ear parts. There is a Mono/Stereo switch about halfway down the headphone wire, which can be somewhat inconvenient if you have to squeeze the wire through a very tight spot, but the ability to switch between the two is helpful for those who like to fiddle with their sound functions. In addition, there’s a sound knob on the left side, but it’s unmarked, so sometimes you may forget that your sound isn’t turned all the way up. Although it looks like the headphone jack is extremely short in the display picture, you can actually stretch that up to about 20 feet, if the thing you’re plugging the wire into is stable enough. However, the part that I was most excited about–the noise reduction–disappointed me the most. I guess I should have expected less-than-great quality for sound blocking, since I *did* pay only $41 for these, but they block about the same amount of sound as if I cupped my hands over my ears. Sound from conversations still manage to creep into the headphones, and unfortunately, it barely even drowned out my roommate’s loud music at all.

However, for quieter, ambient noises, this product blocks them all out. The past week my roommate was working on a paper–without music–and he complained to me that I was typing on my keyboard too loudly (the sounds of which were drowned out completely by these headphones).

Also, some people have complained that the thin metal is sharp enough to cut your hand with. This is completely false. While it does have flat and not rounded edges, I think it’s easier to cut your hand on paper than it is to cut it on the metal on this product.

Bottom line–a mediocre product with little noise reduction capability. It might be better to shell out a few more dollars for a higher quality product.

Customer questions & answers

Q: i am from chile..which is the cost of shipping ? or is included in the price?

A: N/A

Q: How many decidels does this reduce?

A: Just about zero

Q: How many dBs does it reduce?

A: Not a clue. I used these for transcription work, not music. Crispness of sound was not the best. Second Koss set I purchased had a headpiece that pinched my head so bad I had to return them. I now use Senal SMH-1000 Closed-Back Professional Monitor Headphones. Noise reduction is not as good as the Koss, but the crispness of sound is far superior.

Q: Does it have a small or,large connector end? I,would,need to plug it into my iphone without an adaptor….thanks

A: it has the small end, i use it on my ipod and they work great

Q: What is the size of plug?

A: It has a 3.5mm (cell phone size) plug on the cord. It comes with a 1/4 inch adapter for older equipment or perhaps communication devices. Hope this helps.

Q: Is it made in chinaJust a question.

A: Did not notice but isn’t everything made in China?

The Koss QZ99 punches above its weight with balanced, detailed sound and a portable form factor. While better headphones exist, few can compete at this low price point. For budget-conscious listeners wanting great all-around audio, the QZ99 is a top choice.


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