Sennheiser HD 660S2
The HD 660S2 is an open-back reference at 300 ohms — the HD 660S successor with deeper sub-bass extension — scoring 65 at the enthusiast tier. It is tuned for critical at-home mixing and listening, not tracking (open-backs bleed) or portable use, and it wants a capable headphone amp: run it off a weak output and you will never hear what it can do.
In Setup Gear Guide's studio
Hands-on · I own this
Kyle Romero — I own and use this
These are my precision and late-night pair. I share walls, so a lot of my work happens on headphones, and in a small, lightly-treated room the low end on speakers can lie to you — so the careful, detailed calls get made here.
I run SoundID Reference on both these and the Barefoots, which flattens each to a neutral target. The way I split it: the Barefoots are for vibe and feel, and when the speakers and the room disagree, the 660S2s break the tie.
This is my own unit, photographed in my studio. Owning it never changes its score — how I score. See the full rig: my studio.
Scores
BreakdownHideOverall68±3Caliber-forward blend — tier caliber + within-tier price rank 30%, value 25%, confidence 20%, compatibility 15%, upgrade path 10% — renormalized over applicable dimensions; excluded here: compatibility (no ecosystem dimension).
Scores
BreakdownHideCaliber-forward blend — tier caliber + within-tier price rank 30%, value 25%, confidence 20%, compatibility 15%, upgrade path 10% — renormalized over applicable dimensions; excluded here: compatibility (no ecosystem dimension).
The ± band on the overall score reflects sourcing confidence — wider when fewer specs are verified.
How each score is computed: our scoring methodology.
Specifications
| Spec | Value | Verification |
|---|---|---|
| design | openSourced | Sourced |
| impedance ohms | 300Sourced | Sourced |
2/2 detail specs sourced. Amber rows are flagged for verification — we show them as reported, not confirmed.
Verdict
Best for
- Open-back mixing/reference detail — the HD 660S successor with deeper bass extension
Who should skip this
- Tracking (open-back bleed); needs a capable headphone amp (300 Ω)
Where to buy
List price $600
Prices are a guide and can change — confirm the current price on the retailer's site before buying.
Prices last checked Jun 27, 2026 — retailer prices change often, so click through for the current price.
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Compatibility
No platform-specific compatibility requirements — this works in any standard music production setup.
Upgrade path
Buying today, the Audio-Technica ATH-M50x scores higher for less — the smarter pick in headphones unless you specifically want this one. See it →