Thank you for the work you do on your site. I discovered it after I purchased a new pair of Sennheiser HD599 HP. I previously owned a pair of Koss 4XTC HP, which I have owned for many years, and had enjoyed(the ear pads are shot, and I can't purchase new ones). Anyhow, because my Koss are shedding on my ears, I decided to purchase new phones. I mainly listen to a lot of classical music. I read many reviews for the HD598 and 599, and the VAST majority of them indicated that the 598C was a very good HP, and yet there were improvements in the 599, so I purchased the 599s through Amazon. I have listened to them over the past couple of days and I can't help but hear a muddy bass and a an attenuated treble. I know these recordings don't sound that way on speakers. Please tell me if new headphones need to be broken in, and for how long. Will the muddy bass and treble improve? What are better, not breaking-the-bank HP for listening to classical music? What is considered "critical listening". Thanks for your response.