Headphones and Earphones
- Written by Chris Groppi
- Published on 26 November 2009
On the Bench
As with the Denon AH-D7000s, I did not have the proper equipment to measure the HD-800s. Tyll Herstens and Ivy Burford at Headroom were happy to provide me with their measurements of the HD-800s. These are made with an artificial head system that has microphones located in simulated human ears. They are the most accurate way to measure headphones, but the results require some interpretation. At high frequencies, the ridges and folds in the ear cause response peaks and dips. These are not due to the headphones themselves. Loudspeakers are measured with bare microphones, and therefore do not show these effects. Our brains apply “EQ” to fix these peaks and dips, so flat response ends up sounding flat to us.
If you’re interested in comparisons, Headroom’s website has an interactive graph builder that can overplot measurements of several headphones, drawing data from their extensive database of measurements. Complete sets of acoustical and electronic measurements are available for ALL the headphones Headroom sells (dozens of models).
The frequency response of the HD-800s goes spectacularly low. Given that headroom’s normalization to 0 dB at 1 kHz seems to be about 3 dB too high to me, the bass gets to its -3 dB point at about 12 Hz (!). The shape of the bass response as compared to the Denons is definitely flatter overall and goes much deeper. The Denons have a broad response plateau which doesn’t roll off at all until 30 Hz, while the HD-800s have a more rounded response with a peak at about 100 Hz.
The harmonic distortion spectrum of a 500 Hz tone shows that the second harmonic peak is at -85 dB, with the third harmonic at -80 dB. The second harmonic peak is 10 dB better than the already fantastic Denons. This performance is just ridiculous, and shows why headphones like the HD-800s NEED a high performance headphone amp. Their intrinsic distortion is so low that anything but the best will end up dominating the distortion of the system. For comparison this level of distortion is something like 25 dB better than what the very best loudspeakers can deliver.
Isolation below 1 kHz is non-existent. These are not headphones for listening in environments with background noise.