Sennheiser HiRes Audiophile Headphone (HD 660 S)

Product Information

But you could always add some more bass boost in Roon, and play with it until you get something you like. The pure and effortless sound of the HD 660S is reflected in its new matte black and anthracite design. connector opens a pathway to a newer generation of balanced output devices (headphone amplifiers, digital audio players, etc. However, they are definitely not perfect, and–I think more importantly for the HD 660S–there is the question of value; which I will discuss towards the conclusion of this review. if some people can comment on the results they get with HD600 or 650 with Mojo, you are welcome, as the reply from Musikverein lets me believe it’s maybe not ideal).

While the HD 660 S was a bit brighter than the other two, it also lacked the nuanced resolution and dynamic balance of the 600/650. Their bass is very good, consistent, and punchy, the mid-range is well-balanced and clear, and their treble is very good as well.

They won’t be great for any other use as their open design doesn’t block any noise and leaks a lot, so they're best used in a quiet listening room where you can really benefit from their sound quality.

Finally, and perhaps the most exciting change we see, is the new tuning on the S2: a little more treble, and significantly more extension on mid and sub bass. The Sennheiser representative said the HD 660 S will replace the HD 650 in the line-up, and the older model will be discontinued.It’s a forwardness in the neighborhood of 1KHz and/or on the first one or two harmonics above it (when I make the sound ‘ooooowwwww’ into a spectrum analyzer the dominant frequency on the vowel sound is around 930Hz, which also means harmonic spikes occur again at around 1860Hz and 2790Hz). In that regard you would be inclined to say the HD 660S is rather related to the HD700 and not the HD600/650 series but I assume that it marketing wise is better to link the newest creation to the successful and iconic HD650.