Sennheiser HD 800 S Open-Back Headphones Review
When Sennheiser launched the original HD 800 of which the S is an improved version in 2009, none of us knew just how momentous the next decade would be for headphones, driven principally by the arrival and rise to ubiquity of the smartphone and the dawn of hi-res portable digital music players. Before we knew it, everyone and his dog was making headphones, planar magnetics were having an unlikely renaissance, speaker manufacturers sought a slice of the action, and people wore not just earbuds on public transport but large circumaurals too. With no trace of embarrassment.
As the headphone furore begins to die back, the L1400 HD 800 S continues its serene progress as Sennheiser's top open-back moving coil model (only the closed-back HD 820 and rarefied electrostatic Orpheus HE 1 are costlier) as if none of this had happened. And remarkably, if it were to be introduced today it would garner much the same awed plaudits the original did all those years ago because it is still a distinctively modern-looking headphone, as clean a break from the staid HD 650 as you could imagine. Sennheiser calls it a design classic, and for once that's not hyperbole.
Plus the HD 800 S still delivers a neutrality and accuracy of sound that most competitors strive to emulate. It has sometimes been criticized for being too bright sounding, but that's the price of reacquaintance with what high fidelity means in a market area where excess bass and recessed treble have become a norm. (I think of it as the new radiogram era except that many of those who espouse it will have no idea what a radiogram was. Nice tone, mate.) Still, there's a simple tweak that makes the HD 800 S sound even better, which I will vouchsafe in due course.
At the heart of the design is a 56mm driver reminiscent of but much larger than a ring tweeter, the radiating area being a domed annulus. Sennheiser calls the driver "the largest ever used in dynamic headphones". In common with an increasing number of today's circumaural headphones, the driver is fitted into the capsule at an angle, within the apex of a shallow cone of fine stainless steel mesh. Angling the driver in this way, to more closely approximate the arrival of sound from loudspeakers, is intended to engage the pinna (external ear) more fully, and create a more spacious soundstage as a result. Nominal impedance is a high 300 Ohms, as a result of which the voltage sensitivity is roughly 10dB less than typical of modern medium impedance headphones.
The Y-cable attaches to each capsule via chunky two-pin ODU connectors which are far more rugged than the flimsy two-pronged plastic things used in the HD 650. Two long (3.45-meter) cables are provided as standard, terminated in a 6.3mm TRS (tip-ring-sleeve) jack plug and a 4.4mm TRRRS Pentaconn plug for unbalanced and balanced connection respectively. Note that connection to 3.5mm mini-jack outlets is not supported, nor is any short cable supplied a clear indication that Sennheiser intends the HD 800 S for use at home rather than on the hoof.
A stainless steel plate across the top of the headband carries the headphone's serial number, and inside the packaging is a USB flash drive which, as well as the user manual (there's also a hard copy), provides the measured, diffuse-field corrected frequency response of the individual headphone. Nothing else is supplied by way of accessories, other than a microfiber cleaning cloth.
Comfort Is Crucial
Let's not beat about the bush here: if you like your reproduced music sugar-coated, if you prefer a rose-tinted view, then the HD 800 S isn't for you. It doesn't serve up a quagmire of bass excess, and it doesn't do 'polite' treble. If you ask me its' proper hi-fi because it's unflinching its truth-telling. Most 70s rock recordings sound lackluster through it, and I have little difficulty believing that they sounded that way in the studio. But the HD 800 S is not the least ageist. Nobody could accuse it of that who has heard it deliver Nat King Cole's masterly Welcome To The Club (88.2kHz/24-bit conversion from the Audio Fidelity SACD release) or Old Blue Eyes wowing the audience, and having fun with the Count Basie Orchestra, on I've Got A Crush On You from Sinatra Live At The Sands (192kHz/24-bit rip from Reprise 8122 73777-9). Both effortlessly shed the decades.
And the HD 800 S is a true chameleon. How do you like your violin sound? Sweet and sonorous as in the late Dave Wilson's recording of Beethoven's Violin Sonata op 96 (176.4kHz/24-bit download from Wilson Audiophile Recordings label), or spiky and unsettling as in Webern's Rasch from Five Pieces for Violin and Piano (2L Records, 24/96 download). No matter: the HD 800 S does both, as required.
I found it particularly persuasive on voice, and not afflicted by the sibilance the 6.3kHz peak in its corrected frequency response might suggest. One of the severest tests I have of this is Sabina Sciubba and Antonio Forcione's Take Five from Meet Me In London (Naim label 192kHz/24-bit download). Some headphones have made me shout an involuntary 'Ouch' when sizzling on its sibilants, but the HD 800 S handled them well without the severe test the result of which can spoil what is otherwise fabulous music making, with Sciubba deploying every vocal trick in the book to be a femme fatale.
Oh, my simple tweak? I almost forgot. Take the dust covers out from within each capsule. They are easy to remove, and just as easy to replace should you prefer them in place. When I first reviewed the HD 800 S in 2016 I noted that it sounded better with these removed. Revisiting the headphone over four years later I find, just as then, that I enjoy even more audio umami with them eliminated, even though it makes barely any change to the measured frequency response.
That wiggle in the uncorrected responses at around 50Hz is due to a headband resonance, but in other respects the HD 800 S is a remarkably low-resonance design, as confirmed by its clean cumulative spectral decay waterfall. It may not use beryllium or other exotic diaphragm material, but it betters most competitors that do, and most planar magnetic and electrostatic models as well.
These responses assume a good seal to the listener's head. If that isn't achieved for instance, because of thick spectacle frames or because the headphone is worn over hair then there is a mild loss of lower-midrange output and larger loss in the bass, amounting to around 6dB at 20Hz in my testing.
As you'd expect of a true open-back design, the HD 800 S provides no effective isolation of external sound below 1kHz and only modest attenuation at higher frequencies. As a result, it achieves no significant reduction of the many environmental sounds that are dominated by low frequencies, such as car cabin or aircraft cabin noise. In domestic usage the setting for which the HD 800 S is clearly intended this will be less of an issue, but a quiet room is necessary to enjoy it without interruption.
Voltage sensitivity is on the low side at around 106dB SPL for 1 Volt at 1kHz, because of the high impedance, which varies between 599 Ohms at 129Hz and 322 Ohms at 2.07kHz. But this means that frequency response change due to finite source impedance is low for a moving coil headphone, even a 30 Ohms source resulting in only a 0.35dB modification. Full measurement results can be viewed at headphonetestlab.co.uk.