I've read a lot of diverging comments about these headphones and I think there is a problem. These are non-powered studio monitor headphones. They are not meant to have perfect sound quality, and especially not without a proper amplifier. Using them with a tube headphone amp the quality increases like crazy. Because they are studio monitor headphones, they are supposed to have very little influence on the signal themselves, and in a studio, you'll probably have at least a half-decent headphone amp. Used with an iPod, you do have to turn up the volume...