The headphones you buy when sound is the only thing that matters

Sennheiser HD 660S2

Name: Sennheiser HD 660S2
SKU: B0C33XXG7X
Price: 407.89 USD
Rating: 8.9 (1 reviews)

8.9/10high confidenceLast checked Jun 19, 2026

Er

Reviewed by

Eran Yorkovsky · Founder, PickGrade

Sound first, everything else a distant second. The HD 660S2 deliver the classic Sennheiser midrange, smooth, spacious, and easy on the ears for hours. The catch is everything else: no isolation, no wireless, no ANC, and they want a headphone amp to open up.

Headphones for the person who turns the lights down and just listens. The HD 660S2 are the latest in Sennheiser's revered 600 line, tuned for a smooth, spacious, almost effortless midrange that makes vocals and acoustic music glow, with a little more low end than the originals. They're open-back, so they leak in both directions and block nothing, and the 300-ohm drivers really come alive on a proper headphone amp. Strictly a quiet-room machine, but a glorious one.

$407.89

$679.95

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Last reviewed Jun 5, 2026

AI grade·Refined by real owners

What we like

✓Natural detailed sound
✓Comfortable for long listening
✓Great for dedicated home setups

Trade-offs

−No isolation and leaks sound both ways - unsuitable for commuting, offices, or travel
−No wireless, ANC, or app features
−300-ohm drivers benefit from a dedicated headphone amp to fully open up
−Some listeners find the bass soft and the dynamics gentle rather than punchy

Best for

At-home listeners who want spacious, detailed open-back sound and are willing to pair it with a headphone amp.

Avoid if

You need noise isolation, portability, wireless, or a built-in mic — open-back headphones leak sound both ways.

The three lenses

How we grade →

Value & Longevity · Eran Yorkovsky
3.5/10
Design & Fit · Michal Zucker
9.0/10
Health & Environment · Dr. Yocheved Yorkovsky
6.2/10

Score breakdown

sound quality9.6/10
comfort fit9.0/10
value8.0/10
battery features2.5/10
noise control2.0/10
mic calls1.0/10

Specs

type: Open-back wired over-ear
cables: Balanced 4.4 mm + unbalanced 6.35 mm, plus 3.5 mm adapter
driver: 38 mm dynamic transducer, aluminum voice coil
best use: Home and studio listening
features: None (no wireless/ANC) - tuned purely for sound
impedance: 300 ohms (benefits from a headphone amp)
isolation: None - open-back leaks sound both ways

How we know

High confidenceLast checked Jun 19, 2026

The Sennheiser HD 660S2 are open-back headphones built for one thing — sound — and they deliver the smooth, spacious, naturally detailed presentation reviewers consistently praise, especially in the midrange where vocals and acoustic instruments shine. They're the latest evolution of Sennheiser's legendary 600-series, with a new 38mm transducer and an ultra-light aluminum voice coil, plus a touch more low-bass weight than the original HD 660S while keeping the line's balanced, non-fatiguing character. The build is understated and comfortable for long sessions, and the box includes both balanced (4.4mm) and unbalanced (6.35mm) cables along with a 3.5mm adapter. The trade-offs are exactly what open-back audiophile implies: there's no noise isolation and they leak sound freely, so they're for quiet home or studio listening, not commuting or offices. There's no wireless, ANC, or app, the 300-ohm drivers benefit from a dedicated headphone amp to fully open up, and some listeners find the bass a little soft and the dynamics gentle rather than punchy. For someone who wants reference-grade, easy-to-love sound at home and already has — or will add — an amp, they're a standout; anyone needing isolation, portability, or features should look elsewhere.

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