HD 660S2 vs HD 660S2
A side-by-side readout for sensitivity.
Understanding sensitivity
Sensitivity tells you how much volume a transducer produces per unit of input power. A 100 dB/mW headphone hits 100 dB SPL with 1 mW; an 85 dB/mW headphone needs ~32× more power for the same volume.
Comfortable listening
- Conversation / background music — 60–70 dB.
- Engaged listening — 75–85 dB.
- Loud / hearing-damage zone (sustained) — 90+ dB.
Pairing with sources
A phone's headphone-jack DAC outputs ~25 mW into 32 Ω. With a 100 dB/mW headphone, that's 114 dB peak — plenty. With an 85 dB/mW, you might only get peaks around 99 dB — comfortable max, no headroom for transients.
This matchupIn this spec, HD 660S2 and HD 660S2 are effectively tied at 104dB — buyers can treat them as equivalent on sensitivity alone.
What is sensitivity?
How loud a headphone or speaker plays at a given input power, expressed in dB/mW (headphones) or dB/W (speakers). Higher sensitivity = louder at lower power.
Read the full Sensitivity explainer →Other specs on this comparison
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