Denon has engineered our Urban Raver headphones with key technologies to deliver a bone-jarring, brutally powerful bass experience. Denon's Urban Raver AH-D400 Over-Ear headphones feature a 50 millimeter driver, a built-in headphone amplifier and rechargeable battery for explosive sound. You can choose between two different sound signatures -- amplifier on for pulse-pounding bass or amplifier off for a slightly accentuated bass experience. The rechargeable battery lasts for 12 hours,....