The sound quality is crisp and clear for both parties, and the earpiece expands and contracts for different sized ears. A shame as Ive been wearing Teva for some 20 years. I am a headphone enthusiast and own numerous headphones many of which are more expensive than the Philips SHP9500. no break in period needed. Now, there?s nothing about the QC 35 IIs? sound to complain about: it is as clean and sharp as our new breadknife; and they are really very good at distributing music around the interior of my noggin in a way that is immensely pleasing). But, this is my daughter in law?s favorite color right now. I cant give this brand a higher rating! When it stopped working recently, I decided to try this less expensive wired option. Because this speaker is GREAT! Actually sometimes its too much like the seal they provide.