Sennheiser HD 660S2 Review

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Bass, Mids, Treble

The HD 660S2’s most important part probably is the bass section, especially if you ask Sennheiser who is clearly focusing on this part in their communications. “Extended sub bass for a deeply moving experience” is what they’re calling it.

Yes, it’s clear that the HD 660 S2 has an elevated bass presence over the original. We’ll dive into a more detailed comparison between both versions in a bit. Bass on all levels has good body and the sub bass has certainly improved. That said, it’s still no sub bass monster when it comes to quantity. The HD 660S2 is more mid bass focused. Everything is still civilized and closer to neutral than it is to the bass heavier side*. Bass is exciting and engaging, always well controlled and tight in the delivery. Note that the bass quantity does depend on the amplifier used*, and it’s easy to make bass lighter or bass heavier combos.  Bass depth as said is good, just like the layering but the driver does have limits in this design. Don’t expect HD 800 (S) technical levels.

After the bass section, surely the treble section is most exciting and most retuned. Treble is lively and energetic, with a spacious, clean, and precise delivery. Treble extends well but always is perfectly controlled. The popular peak is still their around 3kHz and the roll-off starts around 8kHz but you never get the feeling of missing out. At the same time treble is always clean and lively to the ear, never becoming harsh, sharp, or unpleasant. For me this tuning works really well.

The least difference was made to the mids, and that part clearly shows. I do feel that in the S2 the clarity and vocal precision is higher than in the original. While it’s still a smoother delivery, there is less darkness and that’s a plus in my book.

Comparisons

HD 660S

Multiple references have already been made up to now, but let’s summarize the main differences.

The HD 660S2 S2 has improved clarity and cleanness and it overall (but especially in the mids) sounds cleaner. Overall, the S2 sounds more balanced with less mid congestion and cleaner, slightly more forward vocals. As mentioned, multiple times already, the lower end now has more weight and (sub)presence, but it doesn’t exaggerate.

With the improved low-end, more extended, and lively treble, higher clarity and improved precision/extension, the HD 660 S2 produces a higher-end, more balanced sound. The original S doesn’t have the same level of energy, extension and excitement and that combined with an even darker/warmer presentation makes it a duller sounding headphone than the S2.

For my ears the choice is easy, but you might of course prefer the slower, darker and lighter character of the S more.

HD 650

The Sennheiser HD 650 for many still is the old King, especially with a good OTL tube headphone amplifier like the Crack or LaFigaro 339. It’s still available on Amazon for around $330 USD. While the HD 650 will always have a special place in my heart, I must admit that I rarely use it anymore in my office. I, of the Sennheiser range, tend to use the HD 800 S and now the HD 660S2 a whole lot more.

The HD650 isn’t as pronounced, fast and tight as the HD 660S2. It’s slower, warmer, and smoother but it is still very pleasing to the ear. I do find the HD 650 to have better layering, a more natural vocal presentation, and more impressive sub rumble than the HD 660S2, but the latter one for sure is the best technical performer overall.

If you love smoothness, warmth, a soft top-end, and a slower pace combined with an incredible musical performance, the HD650 is still your to-go-to headphone. If you prefer a more neutral tuning with better control, higher bass presence, increased PRaT and top-end excitement, the never HD 660S2 is the easy choice. Where I can’t recommend the HD650 for all musical genres, the HD 660S2 does everything effortlessly. These headphones are so very differently tuned, and they have a very different approach to presenting music. The HD650 will always be impressive, but for most people the HD 660S2 will be the easy choice as it’s more modern (also in tuning), a better overall performer no matter the musical genre, and less amplifier dependent.

At the moment I don’t have the HD600 here with me, but as soon as it makes its way back to the HQ, I’ll add a comparison to this article.

HD 560S

The Sennheiser HD 560S is selling on Amazon for around $173 USD only. I have to admit a only very rarely use it when I need to do specific comparisons for reviews. What I dislike most about the HD 560S is that it uses a very specific 2.5mm stereo cable, but ok.

For the price the HD 560S is selling for, the headphone is hard to beat. When compared to the HD 660S2 however, it’s not really a competition. The HD 660S2 is technically better in every way. The HD 560S is slower, denser, less airy, and less wide. It doesn’t have the precision, extension, and dynamics of its bigger brother but that’s perfectly ok. The bass presence is more similar, but it is more about quantity where the HD 560S it is about quality. The HD 660S2 has it all.

The treble section is also very different here. While this part isn’t particularly good or outspoken in the HD 560S it plays a prominent role in the HD 660S2. It technically also is more advance with higher resolution and extension. The HD 560S is a very affordable and nice headphone that is easy to listen to, but the HD 660S2 is miles ahead when it comes to performance.

The article continues on the fourth page with more on Sound. Click here or use the jump system below.

Page 1: Sennheiser, HD 660 S2, Specifications, Box & Accessories

Page 2: Design, Build Quality, Comfort, Sound pt. 1

Page 3: Sound pt. 2, Comparisons

Page 4: Synergy, Conclusion