Sennheiser HD 650 Over-Ear Audiophile HeadphonesExpertly balanced acoustics, luxurious construction and timeless design. The HD 650 has all of the perks of a high performance sports car and none of the quirks. This open back headphone is beloved by audiophiles for its musical, non fatiguing sound while still offering intimate levels of detail. Upon the first note, your favorite tracks reveal their true potential, and each moment of that performance becomes an opportunity to react all over again.