Sennheiser HD 400 PRO are open on-ear headphones, which the company has designated as studio headphones of the HD 400 PRO reference class. Outwardly, the headphones are practically indistinguishable from the Sennheiser HD 560S model .
Sennheiser’s engineers allegedly tried to combine lightness (weight without cable – 240 g), accuracy (total harmonic distortion at a frequency of 1 kHz at 90 dB SPL – better than 0.05%) and comfort provided by comfortable velor ear cushions …
The studio directionality of the Sennheiser HD 400 PRO is indicated at least by their impedance of 120 ohms. It is unlikely that this parameter will be “tough” for low-power mobile sources – on the other hand, the sensitivity of the 400 PRO of 110 dB will be to their liking. However, judging by the presented photos, the manufacturer does not mind using the HD 400 PRO not only for work, but also just to enjoy the correct sound.
The speakers are responsible for it, in the diaphragms of which, according to Sennheiser, a “special mixture of polymers” is used. According to the developers, the magnetic system of the Sennheiser HD 400 PRO is powerful, and the ventilation system is efficient.
All of this is aimed at deeper bass and reduced distortion. The very location of the speakers made their contribution – they are “turned” to the ears. The general goal that the company tried to achieve is neutrality and accuracy.
The kit with the headphones included two cables at once: “straight”, 1.2 m long, and spiral, stretching up to 3 m, with a 3.5 mm plug.
In the US, the Sennheiser HD 400 PRO headphones are already available for $ 250, the manufacturer’s suggested retail price.