"Very disappointing performance; would not recommend."2.5 starson by XSYLUS
Pros: Solid, durable design, Affordable, coiled-cord, single-entry cord, super noise reduction, Koss lifetime warranty.
Cons: Heavy, muddy bass sounds, distort quickly.
Summary: I bought these to replace a pair of UR30's that stopped working. For my purpose these headphones work; I play the drumset in a band and use headphones as my monitor since the noise reduction decreases the volume of the drumset. My UR30's worked great for this and I plan to send my UR30s to Koss for repair under their lifetime warranty. My UR30s worked great for several applications, from my Roland Stage Piano, to my drumset monitor, to my mp3 player, and more. The QZ99s not so much. I plugged the qz99s into my mp3 player and was instantly disapointed at the lack of bass. When I increased the bass on the mp3 players EQ all I got was a real muddy response. As I continued to tweak the EQ and increase the bass I quickly reached the point at which these headphone began to crackle and distort. Extremely disappointing. I put on a pair of Sony clip on headphones using the same bass settings and no distortion whatsoever. Clearly Koss missed the mark with the QZ99s.