Review: Sennheiser HD 400 PRO Studio Reference Headphones
25.01.2022

Review: Sennheiser HD 400 PRO Studio Reference Headphones

Words by Bridgette Baini

Sennheiser Australia | RRP $449

The market for open back headphones has really expanded in recent times, which makes a tonne of sense considering their small footprint, broad soundstage, and superior flatness for on the go mixing. 

The Sennheiser HD 400 PRO Studio Reference Headphones are the latest release in a line of highly regarded Sennheiser professional headphones such as the HD 600 and 650, however unlike their forebearers, the 400 Pros look to be aimed firmly at the itinerant mix engineer, rather than the budding audiophile.

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On paper you get an incredibly well priced, high-quality, clean, and neutral output, but in the flesh, it’s the incredible comfort and lightweight nature of the design that really jumps out, especially to anyone looking to embark on some lengthy sessions. 

Shipping with a 3m single-sided coiled cable for freedom of movement, a 3.5mm jack plug to a 6.3mm adapter, as well as a 1.8m straight cable which is better suited for travelling situations, the HD 400 Pro is akin to the HD 600 and 650 in the looks department, save for its plastic frame. This isn’t a bad thing at all and one of the obvious fruits of this design is the 240g extremely lightweight design, which is perfect for all-day usage. Their velour earpads, adjustable headband, and articulating earcups are all durable and of high quality, echoing Sennheiser’s stellar reputation in the professional headphone space. 

sennheiser hd 400 pro headphones

While their isolation does require a somewhat snug fit with ample clamping force, the plastic chassis has just enough give and wear-in to ensure a perfect fit after a few wears. I personally found them very comfortable and didn’t get that usual pain in the cartilage of my ears. Relevant to my head, the narrow earpads gave me plenty of room and breathability.

The interior of the cup is spacious and its metal grill is ever so slightly smaller than the 600 but allows for good circulation whilst avoiding the dreaded pressure build-up in the low mids. This provides a more honest representation of sound and avoids any false reading of frequencies, which is imperative to the decision making process at mix. For added comfort there is also a little notch in the centre band’s padding for an even distribution of pressure, saving the centre topmost part of your noggin.

Optimised for studio setups, the HD 400 Pro’s have a listed impedance of 120 ohms, along with a frequency response of 6 Hz to 38 kHz (-10 dB), a sound pressure level (SPL) of 110dB and less than (<) 0.05% total harmonic distortion, which translates into some pretty impressive reproduction. One of the most distinguishable features of the HD 400 Pro especially when compared to its older siblings, like the 600 and 650 are the slight peaks in the higher frequencies which make them absolutely ideal for balancing out snares, edgy synths, and other mix tasks that tend to require a chiselled high end.

The HD 400 PRO features angled transducers, and combined with its open ear cups, can produce a wide and accurate soundstage. This choice of angled transducers (which is becoming more and more common) is said to provide greatly improved distortion characteristics, particularly at a high sound pressure level, which is very apparent on first listen.

Transients form and dissipate with a purity that really allows you to hone in on a sound in minute detail. This combined with its open-back design, provides a vast soundscape which stretches across the peripherals and envelopes the listener with an incredible clarity that is sure to impress. This is never more apparent than when assessing panning decisions and where everything sits across the the stereo field. 

Sennheiser’s highly touted proprietary self-developed 120-ohm transducers do provide an incredible accuracy and present a very clear image of your mix. The driver magnet ensures clarity while its damping system manages ventilation and this combination gives us a deeper bass, all while accommodating for, and counteracting distortion that would otherwise impact the quality of sound. Of course, at a lower price the omission of extras such as a bag or a carry case are unsurprising, but for what the HD 400 PRO lacks in bells and whistles, it makes up for in performance, practicality, and affordability. 

The importance of peripheral tools in a recording space shouldn’t be overlooked, especially with ITB mixing and small footprint work being such a staple of the production landscape. In this kind of environment, Reference-grade headphones are worth their weight in gold, in turn allowing for maximum translatability from one system to the next.

Where the HD 400 PRO gets it so right is understanding that in the pro space practical features like comfort, durability, and replaceability (ie redundancy) are in many ways, just as important as reproduction quality and this is undoubtedly where they excel. They provide awesome professional quality reproduction and are priced in a manner in which you won’t be too precious about chucking them in your overnight bag or hand luggage.

For more information on the HD 400 PRO headphones, head to Sennheiser Australia.