Maximize your head-fi experience no matter the source or location with Sony MDR1ADAC headphones. Connect your: smartphone, portable audio player, or PC and prepare for ultra-responsive, Hi-Res audio performance paired with lush, enfolding comfort. The internal battery delivers up to 7.5 hours battery, while passive mode can deliver conventional, corded operation without battery. Cord Length: 3.94 ft; Frequency Response: 4â€"40,000Hz (digital), 4â€"100,000Hz (analog); Volume Sensor: Yes (Rotary)