From the ManufacturerSennheiser HD 600The HD 600 is an audiophile-grade open dynamic hi-fi/professional stereo headphone. The advanced diaphragm design eliminates standing waves resulting in a clean sound free of artifacts and acoustical disturbances. The HD 600 is a fantastic addition to a hi-fi stack or dedicated listening room, and is a favorite among mastering engineers worldwide. Natural, spatial imaging Exceptional transient response Optimized for hi-resolution recordings Made in Ireland Learn more about the HD 600I have used my HD 600s for casual and critical listening ever since I got my pair. I can depend on the HD 600 in many different environments and can always expect great results out of it. -Kazuri Arai, Recording/Mix EngineerFeatures High-quality open metal mesh grilles deliver extremely transparent sound Computer optimized magnet systems minimize harmonic and intermodulation distortion Extremely lightweight aluminum voice coils ensure excellent transient response Neodymium ferrous magnet systems ensure optimum sensitivity and an excellent dynamic response Exceptionally natural, spatial and accurate sound Detachable, Kevlar reinforced, OFC copper cable Peace of mind - thanks to the 2-year international warranty Did you know?The HD 600 is a true audiophile headphone designed for one of the best listening experiences. Optimized for minimum distortion, the HD 600 features Open-Aire speakers for a natural listening experience. Sennheiser recommends this headset for...... The HD 600 is geared for your hi-fi stereo system. Best suited for all types of audio the HD 600 is a favorite among mastering engineers worldwide. What theyre saying...I have used my HD 600s for casual and critical listening ever since I got my pair. I can depend on the HD 600 in many different environments and can always expect great results out of it. -Kazuri Arai, Recording/Mix Engineer WarrantyThe HD 600 is covered by a 2-year international warranty. Comparison table HD 600 HD 650 Frequency response 12 - 39000 Hz 10 - 39500 Hz Impedance 300 ohms 300 ohms Transducer principle Dynamic, open Dynamic, open Sound pressure level (SPL) 97 103 dB THD, total harmonic distortion 0.1 % 0.05 % Weight w/o cable 0.57lb (260 g) 0.57lb (260 g) Contact pressure ca. 2,5 N ca. 2,5 N Ear coupling Circumaural Circumaural Jack plug 1/4 / 1/8 (3.5/6.3 mm) stereo 1/4 / 1/8 (3.5/6.3 mm) stereo Warranty 2 Years 2 Years Why Sennheiser ?For over 60 years every Sennheiser mic or headphone comes with a built-in mission: to stay true to the sound and soul the music was given by its artist. From the fragile intimacy of a whispered word to the deep and dark punch of an attacking bassline. Sennheiser delivers pure emotion and excitement. A quality that has convinced a broad spectrum of artists and of course music lovers all over the world. Sennheiser offers a great experience for everyone who really wants to hear. Whats in the box? HD 600 1 adaptor to 1/4 (6.3 mm)Product DescriptionWith the HD 650, audiophiles will experience truly unique natural sound. With sound this good, long concerts in the comfort of your home are a certainty, so the HD 650 also sets standards in comfort and convenience. The HD 650 is a genuine masterpiece, which will satisfy even the most demanding listener. HD 650 the Reference Class.