HD 820
headphones
$2,200
Used market: $1,715*
Specifications
5 of 6 values have a recorded sourceExpert Audio Engineering Commentary
Tonal Profile
The closed HD 800: same 300 ohms, 1 dB more sensitive per volt, Gorilla Glass instead of an open grille. The electrical demand is identical to the HD 800 S, so anything that drove one drives the other.
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.
«Specifications table: 'Total harmonic distortion (THD)' - row left empty; feature list on the same page: 'Total harmonic distortion: 0.02 % (1 kHz 1 Vrms)'»
One page carries the distortion figure twice: once as a number with its conditions in the prose feature list, and once as an empty row in the machine-readable specification table. Anyone reading only the table concludes Sennheiser does not publish THD for this headphone; anyone reading only the prose gets the number without seeing that the table does not repeat it.
checked 8/5/2026* Estimated with the depreciation fallback (~78% retained value). · checked on 8/5/2026