Sennheiser HiRes Audiophile Headphone (HD 660 S)

Product Information

The significant portion of their leakage is spread between 300Hz and 20kHz, which is a very broad range. All the noise of public transit will seep into your audio and people surrounding you will be able to hear what you’re listening to.

There seems to be a slight improvement in depth in the peripherals of the stage – more subtle left and right pans maintained a better sense of distance and proximity. We also measure a more open-sounding soundstage on the HD 650, but since their design is the same, we expect them to sound very similarly. Despite what anyone thinks about what sub and mid bass can do to a reference balance, the extended bass on the HD 660S2 fits like a lost puzzle piece.Upon closer listening, it maintains a slight edge over either Senn in detail retrieval in the bass and the treble. If the 650 is the only one with this smooth signature of the HD6xx line up to the 800s, sennheiser should not discontinue the 650. The HD 650 is a bit too warm sounding for me (just a bit), and the HD 600 is my favorite of the two. The planar magnetic HiFiMan Sundara 2018 are better critical listening headphones than the Sennheiser HD 660 S.

The Sennheiser HD 660s seem like a pretty good option for consuming the more spacious sound that these are well known for.Disclaimer: The Sennheiser HD 660S was sent to us by Sennheiser directly in exchange for this review.