Type: circumaural, open-back, moving coil
Test sample supplied by: Sennheiser electronic GmbH & Co KG
Reviewed in: Hi-Fi News, May 2016
When it was introduced in 2009, the HD 800 - later complemented by this enhanced version - represented a bold design departure for Sennheiser, with the use of advanced constructional materials and choice of a striking, thoroughly modern aesthetic. It was widely welcomed as setting a new standard in headphone sound quality, although for many years since there have been nagging complaints in some quarters that it has an unnaturally bright tonal balance, encouraged, no doubt, by so many modern headphones having reticent treble output.
Little if anything in the HD 800 S's measured performance justifies such criticism. Arguably, it in fact achieves the best objective performance of any headphone I've ever measured.
Because of its high impedance, the HD 800 S has relatively low voltage sensitivity of 105.9dB for 1V at 1kHz, but this will normally mean nothing more than perhaps an increase in required volume setting. Its remarkably high current sensitivity of 116.8dB for 10mA at 1kHz shows that the drive unit's motor design is unusually effective at converting voice coil current into output sound pressure.
While the uncorrected frequency responses display none of the bass lift required to conform to the Harman target curves, elsewhere in the frequency range the response is close enough to the 2017 Harman target that the corrected third-octave response is within ±3dB limits from 80Hz to 16kHz, an unusually fine result that translates into high Harman PPR figures of 84/82 ≡ 73%/72% (L/R).
Just as impressive is the HD 800 S's time domain performance. Its CSD waterfalls are remarkably clean, with just a few well-damped resonances visible in the treble (the peak just above 10kHz probably results from the use of the old GRAS ear simulator for this legacy measurement). Behaviour in the overall impulse response is as near to textbook as you are likely to see, with decay to -40dB taking 2.2ms and 1.8ms respectively and continuing rapidly to lower levels.
Impedance varies by about 2:1 over the audible frequency range but, because the impedance is high, frequency response modifications caused by finite source impedance are small - just 0.13dB for a 10 ohms source, rising to 0.36dB for 30 ohms.