I've noticed very little degrading of the sound, if at all, and this is rare in most extensions. The cord is thicker than usual for both the positive and negative polarities - a separate wire for each - and I'm quite pleased with this, will perhaps get another because of its thickness. I now have great headphone sound within a twenty-foot range - just what I was looking for. Even if you don't need 15-feet of cord, I would recommend this over the shorter 10 foot cords where the wiring is about half as thick and not likely to hold up over time...I subject all my electronics to heavy use. Plus, the best extensions for Grado headphones go for $40, and I'm quite satisfied saving over $30 by having this one.