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1 / 6A new model sits atop the HD 600 line.
A 0.7 puts its noise isolation in the bottom 10% of over-ear headphones we've measured.
Measured on 92 of the 239 we've cataloged.
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Wired-3.5mm is the most common — on 46% of the 248 over-ear headphones we've cataloged (of 239).
below average for over-ear headphones — based on 198 of 239 we've cataloged.
Objective measurements from the SoundGuys test lab — overlay other models to see how this one compares.
Sennheiser HD 660S2 Frequency Response (measured on a B&K 5128)
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Measured frequency response (dB relative) against the SoundGuys Headphone Preference Curve. When the measurement goes above the dashed line, that frequency is louder than our preference curve, and when it goes below: it's quieter. Use the curve for comparison purposes only, as your taste may vary.
| Frequency (Hz) | Response (dB) |
|---|---|
| 20 | -8.5 |
| 25 | -6.4 |
| 32 | -4.7 |
| 40 | -3.2 |
| 50 | -2.3 |
| 63 | -1.8 |
| 80 | -1.5 |
| 100 | -0.7 |
| 125 | -0.4 |
| 160 | -0.5 |
| 200 | -0.6 |
| 250 | -0.5 |
| 315 | -0.7 |
| 400 | -0.8 |
| 500 | -0.8 |
| 630 | -0.5 |
| 800 | 0.0 |
| 1000 | 0.5 |
| 1250 | 1.6 |
| 1600 | 2.3 |
| 2000 | 3.0 |
| 2500 | 5.0 |
| 3150 | 7.2 |
| 4000 | 4.8 |
| 5000 | 3.2 |
| 6300 | 6.9 |
| 8000 | 6.7 |
| 10000 | 3.9 |
| 12500 | -0.3 |
| 16000 | -4.7 |
| 20000 | -18.9 |
Sennheiser HD 660S2 Attenuation (measured on a B&K 5128)
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Solid lines: passive isolation (dB) with ANC off — how much ambient noise the fit blocks on its own. Higher on the chart means more attenuation.
| Frequency (Hz) | Attenuation (dB) |
|---|---|
| 21 | 0.4 |
| 26 | 0.3 |
| 33 | 0.1 |
| 41 | -0.1 |
| 52 | -0.0 |
| 65 | -0.1 |
| 82 | -0.2 |
| 103 | 0.1 |
| 130 | 0.0 |
| 163 | 0.1 |
| 205 | -0.1 |
| 259 | -0.0 |
| 325 | -0.1 |
| 410 | -0.3 |
| 516 | -0.1 |
| 613 | -0.2 |
| 772 | -0.7 |
| 972 | -1.2 |
| 1220 | -1.2 |
| 1540 | 0.1 |
| 1940 | 3.3 |
| 2440 | 8.6 |
| 3070 | 7.2 |
| 3870 | 8.7 |
| 4870 | 11.5 |
| 6130 | 17.8 |
| 7720 | 16.7 |
| 9720 | 15.3 |
| 12200 | 2.3 |
| 15400 | 10.4 |
| 19400 | 11.1 |
The verdict
The Sennheiser HD 660S2 is slightly bassier than its predecessor, but this isn't for bass-heads, and also not for those who need significant treble emphasis. It's not a good or bad thing, it's just a preference issue—but this fact should inform your buying decisions.
✓Liked: Good sound, Easy maintenance, Comfort, Connectivity
✕Could be better: Sound not for everyone, Price
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What readers ask about the Sennheiser HD 660S2, answered by the people who own it.
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2 of 4 would buy again
4 owners · owners report ~40 h per charge vs 40 h claimed
Expected more from the fit and build
The battery beat their expectations
The noise cancelling beat their expectations
1 of 1 would buy again
1 owner
Nothing surprising about comfort
0 of 1 would buy again
1 owner
The noise cancelling beat their expectations
0 of 1 would buy again
1 owner · 1 photo-verified
Expected more from comfort
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Comfort beat their expectations
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1 owner · owners report ~55 h per charge vs 53.77 h claimed
The battery beat their expectations