I’ll be honest here, and at the time of writing, HD660S2’s are a tier up from the entire HD6** lineup and it all comes down to microdetails. The S2 has a balanced, almost linear, lower mid-range that is followed by an emphasized center mid-range while it steers away from the upper mids boosting of the HD650.

Sennheiser HD 660S2 thread - Head-Fi.org Sennheiser HD 660S2 thread - Head-Fi.org

My goal for the reader is hopefully they gain a lot of knowledge about how the HD 660S2 sounds and how it sounds in comparison to the other HD 6 series headphones. For the S2 the music expands out to the sides of my head and a few inches in front of me and higher up. The initial clamping force was medium, it suited my head shape well and never felt too strong but your experience may vary.Before we get to the gritty details, I’m going to start off the review from the very beginning of receiving the HD660S2’s. Though the S2’s may clamp, I actually don’t notice any hinge creaking that the HD660S’s had which is great, so that’s a definite improvement. I used to be able to feel 22khz on an AKG Q701 back when I was 18 but you know what, I’ll take it, good to know my hearing isn’t completely smashed, lol.

Sennheiser HD 660S2 review - SoundGuys

As these are open-backheadphones more geared towards savoring sound at home rather than cranking tunes on the go, they’ll freely leak anything you play through them.Play a more bass-heavy track, though, with more demanding dynamics, and the Sennheiser HD 660S2 start to struggle a tad. The 109 PRO is more fresh and youthful sounding with an abundance of energy and plenty of luminosity but is sometimes touching brightness territory.

Sennheiser HD 660S2 Review - Major HiFi Sennheiser HD 660S2 Review - Major HiFi

The HD650 is modded with the Custom Cans, copper - weight mod that only affects bass technicalities without altering the frequency response. As based on hours of swapping earpads with former Sennheiser headphones, no other earpads come close to the original earpads that maintain the original sound I have come to enjoy from their headphones. Regarding the initial clamp, it’s quite aggressive on S2’s, and this actually hinders my ability to listen to music like my prior Sennheiser headphones where I only focus on the sound. 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. Instruments with the S2’s would exist in its own space and direct all their sound towards me in all of its clarity.I do reviews for me first due the creative intellectual masturbatory pleasure I get out of the process, and I want to get what is hopefully beneficial information out to others. Any reverb near the end of a song can be heard, and artists that sneak in a small vocal line are audible. Image credit: Sennheiser) Analysis: Will these new Sennheiser’s pass the test with audio’s toughest crowd? Sundara’s treble is somewhat grating for me and peaks in the weirdest places that seem to alter speech. This is where the lower mids of the HD660S2’s come in, because the clear and lower and upper mids create such a stark contrast for higher and lower octaves that it plays well for vocals.

Sennheiser HD 660S2 review - What Hi-Fi?

The review sample was loaned by the local Sennheiser distributor for writing a review for "hxosplus" printed edition. 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.Below you will find some useful information about the design principles and the technological innovations of the HD660S2 as provided in the Sennheiser product brochure. On the earpieces themselves you’ll find plush, generously-sized velour earpads which go easy on your ears – it’s like slipping your feet into a pair of posh (and very comfortable) slippers. I soon fell into a rabbit hole of headphones and finally considered the HD600 as my endgame for the past 6 years as I creeped into the age of 28.