With the HD650 and the HD660S the woodwind sound was more balanced and naturally integrated with the strings and the piano when with the S2 got mildly emphasized and artificially highlighted.

HD 660S2 | Sennheiser HD 660S2 | Sennheiser

Meanwhile, over in Beyonce’s ALIEN SUPERSTAR, the HD-660S2’s drivers can capably draw out bass detail in a way lesser headphones would simply miss entirely. These are wired headphones made for the mixing booth, with brilliant sound recreation, plush cushioning, and the rigid headband needed to prevent vibration while you listen to your favorite tracks. The landscape is the same as with the 600 (tonality and timbre) but I see the landscape in a clearer and more expansive way. So this is the new kid on the block and before even publicly released the debate has already started whether it is an upgrade, a downgrade, a side-grade or if it is the real successor to the HD650 or the HD660S etc.What happens is that certain low pitched instruments, like solo bassoon or cello, will sound more "in tune" and realistic with the HD660S when the S2 will add an unnecessarily coloring but you will find the S1 is lacking in intensity and extension with various instruments like low basses or timpani that sound a little muted and not as deep reaching. CSGO/Squad/Insurgency, and I listen to Jpop(rock), Kpop, Pop, classical and almost anything involving instrumentals. The Sennheiser HD 660S2 are an open-backed over-ear design, with this model sporting a 38mm driver complete with an ultra-light aluminium voice coil. The HD 650 draws me to Rock and Roll and the sick amount of Americana music I listen to (in a simplistic way Americana caught on with Johnny Cash and Bob Dylan with “Nashville Skyline” to Lucinda Williams and of course the demigod Neil Young. Even with standard music streaming over Spotify, it’s a pleasant and rewarding experience, hearing the soft croons of Lorde on Buzzcut Season dip in and out as a gentle bass track seems to float in the air around your ears.

Sennheiser HD-660S2 review: easy on the ears at home – but

Unlike many of the best over-ear headphones we've tested, there's no Bluetooth or alternative wireless connectivity other than a detachable cable here.The 660S2’s treble regarding speech on S pronunciations are smooth in comparison, there is no grain and sibilance. Instruments with the S2’s would exist in its own space and direct all their sound towards me in all of its clarity. The soundstage is on the HD650 level regarding width and spaciousness but now it feels more intimate, it positions the listener extremely close to the action, sitting together with the performers rather in front of them and the end feeling is that the music is emanating from the insides of his head. Out of the box, it’s worth noting the clamping weight is a little on the firm side, but there isn’t too much pressure and over time we’d expect this to relax a little.