Sennheiser HD 660S2

The Sennheiser HD 660S2 is a refinement of the long-revered HD 600 family — the open-back wired audiophile cans that have anchored studios and listening rooms for nearly three decades. The 660S2 retains the natural, neutral midrange the line is famous for and pairs it with a redesigned 38 mm transducer whose lower 70 Hz resonance and revised voice-coil and magnet system deliver a noticeably more authoritative low end without compromising the line's reference tonality. At 300 Ω impedance, it benefits from a dedicated headphone amplifier and is one of the few sub-€700 dynamic open-backs that can comfortably scale with high-end source gear.

Key features

• Open-back over-ear design tuned for accurate, fatigue-free long-session listening
• 38 mm transducer with redesigned voice coil and aluminium-coil former
• 70 Hz resonance — a full octave lower than the HD 660S — for deeper bass
• 300 Ω impedance pairs ideally with desktop and portable amps
• Hand-matched driver pairs (within 0.1 dB tolerance) for tight stereo imaging
• Detachable cable; supplied with both 6.3 mm TRS and 4.4 mm balanced cables
• Velour earpads and replaceable headband padding
• Hand-assembled in Wedemark, Germany

Single Black configuration.