The Sennheiser HD-400 Pro is a pair of open-back, circumaural studio headphones that conceal highly sophisticated technology behind an unpretentious appearance. The black headphones impress with a very wide frequency range, from an ultra-low 6 Hz at the bass end of the spectrum to as high as 38 kHz in the treble range. The HD-400 Pro is intended to allow analytical sound judgements to be made. Accordingly, manufacturer Sennheiser describes its sound as natural, transparent, and precise. These headphones also work with Dear Reality's dearVR Mix software. A technology called Spatial Headphone Compensation (SHC) is used here and ensures a reliable assessment of audio mixes in different virtual listening environments so that a mix can be optimised for as many listening situations as possible. The scope of delivery includes two different interchangeable cables with 3.5 mm mini-jack connectors as well as a 6.35 mm jack adapter.
Sennheiser presents the HD-400 Pro headphones as a reference against which the quality of other headphones from the manufacturer should be measured. Its features include angled drivers that are supposed to provide the best possible stereo image. With all of the sound refinements that these dynamic headphones offer, the maximum sound pressure level they produce measures a hefty 110 dB. If the HD-400 Pro is to deliver such a high volume despite its 120-ohm impedance, it is best powered by a headphone amp that can deliver a decent output voltage. For this reason, a separate headphone amp is recommended for laptop users and users of smaller audio interfaces in order to fully exploit the qualities of this open-back, over-ear model.
The Sennheiser HD-400 Pro is a good choice for mix engineers who want to judge ultra-deep bass with their headphones. Mixers who greatly value differentiated highs will also get their money's worth here. And thanks to its low harmonic distortion, audio enthusiasts who expect a very clean signal with hardly any distortion will also find what they are looking for. Fans of high wearing comfort will get a suitable tool with the HD-400 Pro as well: With its replaceable velour ear pads, it lies comfortably on the skin and, with its low weight of only 240 g without the cable, little to no feeling of fatigue can be expected, even during long listening sessions. Those who want to work with their studio headphones in a completely relaxed manner and without pulling on the cable can use the HD-400 Pro's straight cable, which has a practical length of 1.50 metres, instead of the included three-metre coiled cable.
In June 1945, Prof. Fritz Sennheiser founded the Wennebostel Laboratory, which initially produced measuring equipment. Commissioned by Siemens in 1945, the young company developed the MD-1 microphone, which was launched in 1946. After the development of further microphones, the company was renamed Sennheiser Electronic in 1958. Two years later, Sennheiser introduced the MD 421 dynamic microphone, which is still in production today and still held in high esteem by many sound engineers. Further groundbreaking developments, such as the HD 414 headphones and the MD 441 microphone classic, hugely enhanced the company’s international reputation, eventually making Sennheiser one of the leading manufacturers of microphone and headphone systems in the world.
Amateurs will treat themselves to the Sennheiser HD-400 Pro in order to implement high-quality headphone monitoring in their home studio, while owners of project studios will use this circumaural model for signal assessment in multimedia projects. But studio professionals can also turn an ear to the HD-400 Pro: With its light weight, it is ideally suited to use in the control room when it’s time for another long mixing or recording session. Due to the open design, these headphones are primarily suitable for recording situations in which no instruments are recorded via microphone. And despite its compactness, the included coiled cable provides plenty of reach at the control desk, at the mixing console, and in the recording room. In busy situations in the mixing or control room, the single-sided cable connection of the headphones also ensures freedom of movement.