This is my second purchase of the DTX501p, 18 months after the first. I hadn't realized the potential of this amazing headphone since the sound I originally tested had the usual small, lightweight, closed headphone colorations that plague this type of design. When I discovered the Audioforge Parametric equalizer for Apple i-devices, and how it could make those colorations just go away without changing the basic signature, my musical enjoyment increased greatly. I've been working on getting the same results with the 18-band equalizer in Foobar2000, but it's not easy since those 18 bands aren't quite a match for Audioforge's 7 parametric bands. Bottom line: The DTX501p competes with the more expensive headphones I have, and low-cost headphones such as the Sennheiser PX series are not in the same class as the DTX501p.