
Meet the Sennheiser HD 660S
The new HD 660 S is the successor to the legendary HD 650. This open-back, dynamic headphone features new lower (150-ohm) impedance transducers producing reference-class sound when connected to both Hi-Res home or mobile audio systems. An elegantly designed piece of German engineering, the HD 660 S delivers exceptionally accurate and transparent sound, with an expressiveness that immerses the listener in every emotion and nuance of the music.
Sennheiser is shaping the Future of Audio – a vision built on a 70-year history of innovation and a continued drive for excellence that is woven into our company’s DNA and culture. Around the world, our employees share this passion in the pursuit of the perfect sound, creating products that exceed expectations and set new benchmarks in audio.
Did you know? The HD 660 S is designed and engineered in Germany, then manufactured to exacting standards in Sennheiser’s Tulamore, Ireland factory. Every HD 660 S undergoes rigorous, multi-parameter testing to insure performance essential to the most demanding listeners.

Exceptional Sound
Crafted for the demanding listener, the HD 660 S surpasses the performance of its predecessor, the legendary HD 650. Detailed and dynamic, with an extended and balanced frequency response the HD 660 S is both exceptionally accurate and musically expressive. The lower 150-ohm impedance facilitates direct connection to both premium home and mobile audio devices.

Advanced Transducers
The HD 660 S employs newly designed transducers featuring extremely lightweight aluminum voice coils coupled to diaphragms precision crafted from stainless steel fabric. This combination results in exceptional transient response and improved control of diaphragm movement reducing distortion. Additionally, transducers are produced and matched to extremely tight (± 1 dB) tolerance guaranteeing superb performance.

Versatile Connectivity
The HD 660 S is supplied with two para-aramid reinforced detachable cables employing high conductivity OFC copper to insure signal integrity with very low handling noise. One cable is terminated with a 6.35mm stereo plug (a 3.5mm adaptor is also included), the other with the new 4.4 mm Pentaconn balanced stereo plug. Balanced connectivity can reveal full HD 660 S performance potential when paired with the balanced output of digital audio player or headphone amplifier like the Sennheiser HDV 820.

Supreme Comfort
The HD 660 S is designed for pure listening pleasure. It’s open-back architecture is strong yet lightweight, and allows airflow to the ears keeping them cool during listening sessions. The large elliptical ear cups are shaped following the anatomy of the ear, and feature soft velour covered ear cushions. Thick headband padding complete the comfort package to guarantee hours and hours of supreme listening pleasure.

