The sub-bass range in particular is intended to provide outstanding emotions with the HD 660S2. At the same time, according to Sennheiser, an acoustic fine-tuning with optimized airflow around the transducer and a lighter voice coil is supposed to improve the dynamic effect and impulsiveness of the music reproduction. The driver surround has also been redesigned, which is said to have lowered the resonant frequency from 110 to 70 Hertz.
Particularly precision and detail in the lowest frequencies are supposed to have been improved compared to the predecessor. Designed in Germany and manufactured at the Sennheiser factory in Tullamore, Ireland, the headphones have an impedance of 300 ohms, and the ear pads and headband come with a soft padding. The HD 660S2 is delivered with 2 different cables and an adapter for 3.5mm mini jack.
The headphones HD 660S2 from Sennheiser are available immediately in Germany for around €600.