Sennheiser HD 650

Straight to the point

The HD 650 is based on the next model down in the range the HD 600. However, the package is surprising, consisting only of a user manual and a short adapter to mini-jack. Sennheiser has clearly positioned the headphones as a tool purely for the home hi-fi sector, as their detachable cable uses a large jack plug. Like its little brother, the HD 650’s appearance demonstrates a timeless elegance in form and colour.

Service time

The open design is made possible by a grid of fine metal wire recessed at the rear. No matter whether it’s the headrest, the headband or any of the other parts, whichever component is affected over many years of use, Sennheiser servicing can replace it. The user can also replace the ear cushions and the 3 m long cable. The cable uses on a corrosion-proof gold-plated plug, consists of OFC copper inside and secures its strands with a Kevlar sheath.

Headphone fit

The fit of the headphones is ergonomically adjusted as with the HD 600. The size adjustment is sliding and the ear cups can be rotated and swivelled. Thanks to their light weight of just 260 grams without cables, the pleasant contact pressure and the soft velour covers, these over-ear headphones fit like a glove.

Sophisticated technology

The neodymium magnets in the HD-650 headphones are fine-tuned by hand at the factory. Also, this model has new membranes, which allow a low total harmonic distortion of less than 0.05%. The other specifications of the HD 650 are identical to its predecessor. The impedance remains around 300 Ohm and the audio transmission range is from 10 Hz to 41.5 kHz (manufacturer’s specification), which therefore reaches both lower and higher than that of the HD 600. The HD 650 also offers a sound pressure level of 103 dB SPL which, according to the manufacturer, is 6 dB SPL higher than that of the HD 600, but this was not proven by our measurements. In this case, these titanium-coloured headphones only achieve a SPL level of 94 dB.

Sound image

Sennheiser’s promise to give the HD 650 more room, especially for mid-bass, is definitely kept. This makes the sound of these headphones “warmer” than that of the HD 600. The stereo impression and subjective signal resolution are convincing, but the treble of these headphones can be rather reserved. I was therefore positively surprised that this does not have a negative effect on the sound of the HD 650. In fact, I can’t see any big difference between these and the earlier HD 600 headphones, especially since the super-high frequency range is kept within reasonable limits.
The perceived depth gradation is also really good with these Sennheiser headphones. From my point of view, it is minimally affected by mid-range reproduction, which is even more important in this model. Speech, in particular, stands out extremely well. The extended bass reproduction is also very good for the listener using these headphones. The reserves in terms of reproduction volume are just as large here as with the HD 600.