Neumann KH 810 II

Brain meets brawn in Neumann’s powerful new smart subwoofer.

I’ve always been a subwoofer sceptic. The purist in me bridles a little at the bass‑managed 2.1 concept, and I’ve rarely heard a 2.1 system that I am entirely comfortable with. However, the contemporary audio environment is not the same as it was.

Back when subwoofers were first imagined, their role was to enable ‘satellite’ speakers to be made more compact and lounge‑friendly by taking over the responsibility for playing anything below, say 80Hz. And if the satellite speakers were really small, the subwoofer might actually be asked to reach perhaps another octave higher, which for me was a recipe for a decidedly unsatisfactory listening experience. Beginning with the arrival in the early 1990s of 5.1 ‘home cinema’ (and now gaining new momentum with Dolby Atmos and other immersive formats), the subwoofer found a new role: low‑frequency effects (or LFE for short). No longer was the subwoofer simply a crutch for bandwidth‑limited satellites: it was a standalone channel of its own, fed by a discrete signal.

Subwoofers have become an inherently important element of the music production landscape. It’s also a matter of SOS record that my recent experience of Neumann monitors has been very positive. So, when offered the chance to hear how my Neumann KH 150s would perform when combined with one of Neumann’s new subwoofers, it seemed too good an opportunity to miss.

Specs Appeal

The KH 810 II sits in the middle of Neumann’s new subwoofer range. This model comprises a nominally 10‑inch (250mm) driver mounted in an approximately 55L reflex‑loaded enclosure and driven by an amplifier rated at 180W. The enclosure is wood and finished in Neumann’s usual anthracite grey textured paint. The driver is located in one end of the enclosure, protected by a sturdy perforated metal grille, and the connection panel is located in the opposite end. Twin triangular and generously flared reflex ports exit alongside the driver. Being almost twice as deep as it is high and wide (64.5 x 33 x 36.8cm), the enclosure is of somewhat idiosyncratic and slightly awkward dimensions. I’ll explain why a little later.

Neumann’s bandwidth and maximum level specifications for the KH 810 II are respectively 18Hz at ‑3dB and 112dB at 1m (subwoofer located on the floor adjacent to a wall). These are impressive specifications and, in contrast to the majority of monitor and subwoofer specifications I read, are believable. Neumann are very unusual in doing the published monitor specification job extremely well. Only Genelec, to my mind, do this equally well.

The KH 810 II is not short of interesting electro‑acoustic technicalities. Starting with the driver, while its paper diaphragm is conventional, Neumann say its motor system is particularly engineered for linearity, generous diaphragm excursion and, consequently, low distortion. It incorporates Neumann’s “Extremely Linear Force Factor (ELFF) technology and intelligent protection limiters”. Driver‑borne distortion is a significant parameter in subwoofers because the low‑pass filtering necessary for integration with the monitors occurs before the driver in the signal chain, so any driver distortion products appearing at higher frequencies are radiated without attenuation and can begin to become apparent in the upper bass and even low midrange. Subwoofer distortion really needs to be minimised at source. “Intelligent protection limiters” refers to a technique that employs driver excursion control within the subwoofer DSP. This means that the traditional driver engineering technique of building conservative mechanical excursion limiting into the suspension (the surround and/or suspension are engineered to ‘tighten’ before the driver can damage itself by moving too far) is less necessary. That again results in better linearity and lower distortion over the normal excursion range.