HD681
headphones
$35
Used market: $25*
Specifications
3 of 7 values have a recorded sourceExpert Audio Engineering Commentary
Tonal Profile
The headphone that made Superlux a name outside Taiwan: a 50 mm semi-open driver at 32 Ohms and 98 dB/mW, which any phone drives to painful levels. Worth knowing before comparing measurements: the HD681 is sold in three tunings — HD681, HD681B and HD681F — and Superlux publishes one impedance and one sensitivity for all three, so a review of 'the HD681' may not describe the one you bought.
What the datasheet actually says
Quoted verbatim from the manufacturer’s own page, with the date we checked it. We state what is printed, not what anyone intended by it.
«The HD681 series headphones offer 3 distinctive sound profiles, each with its own character. ... Sensitivity: 98 dB SPL (1 mW) ... Rated Impedance: 32 Ω»
One sensitivity and one impedance are printed for three models the same page describes as having three distinctive sound profiles. A frequency response that differs between HD681, HD681B and HD681F must change the sound pressure at a given voltage somewhere in the band, so a single 98 dB SPL (1 mW) figure cannot describe all three at every frequency. Treat the number as the family's nominal figure, not as a measurement of the specific variant.
checked 8/5/2026* Estimated with the depreciation fallback (~71% retained value). · checked on 8/5/2026