Sony Headphones MDR7509 The MDR-7509 is a high-quality stereo headphone for critical and demanding professional application, including studio and broadcast monitoring. MDR-7509PAC2 consists of (2) model MDR-7509s in a master carton. Circum-aural design covers the entire ear for tight acoustic seal and extreme comfort. Wide frequency response (5-30, 00Hz) for accurate sound reproduction. Extreme power handling (3000mW) for the most demanding music applications. 50mm drivers for superior bass response and low distortion. Neodymium magnet for superior bass response and sensitivity. Amorphous diamond evaporated diaphragm provides natural sound reproduction. Reversible ear-cup design allows signal-sided monitoring. Self-muting mechanism prevents leakage when headphones are taken off. Gold-plated Uni-match plug, for compatibility with a variety of audio components. Convenient folding design for easy portability. Coiled LC-OFC cord for low signal loss.