The Von Schweikert UniField One loudspeaker (Hi-Fi+ 75)

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Von Schweikert Audio UniField One
The Von Schweikert UniField One loudspeaker (Hi-Fi+ 75)

The Von Schweikert UniField One loudspeaker is the perfect example of the dichotomy between the sort of small room speaker UK listeners require and the kind of speaker that works in the larger rooms of our US counterparts. The Unifield One is the sort of forgotten loudspeaker in American territories and yet is probably the most valuable player in the team here in Blighty.

That ‘UniField’ part of the name comes from the term ‘unified sound field’ design, a concept that theoretically makes the speaker independent of the room itself. This works by combining a drive unit arrangement with excellent on and off-axis performance with a very inert cabinet. The loudspeaker effectively has no output to the rear and sides of the cabinet, so any boundary interaction (or lack thereof) is immaterial to the sound. Which means the loudspeaker will work in a cabinet, on a wall or in free space with little change in tonality, even if the wall does reinforce the bass response.

How this works is using a triple-wall cabinet structure, combining a medium Q resin-impregnated MDF outer shell with a high Q artificial stone damping blocks and then a low Q inner coating of hard felt, all bonded together with a rubberised adhesive, which itself acts as a constrained layer and thereby helps damp vibration transmitted from layer to layer. The whole point of this is to combine the benefits of all three types of material in a manner usually only possible with very high-mass, thick walled cabinets. Nevertheless, the composite cabinet still is almost 6.5cm thick, but it does take a piano gloss well. The internal void is filled with little fluffy clouds of Dacron wadding, although with a twist – the closer you get to the cabinet walls, the denser the Dacron, in a manner suggested to provide absorption without reflection back into the cone. Inside the cabinet, the UniField One is divided up into three chambers, in what von Schweirkert calls a ‘hybrid transmission line’.

The cabinet itself looks like a well-made but relatively commonplace chamfered cabinet, with a rear panel wide enough to take a beefy single set of rhodium-plated 4mm posts (that can also take a set of spade lugs). This also has a relatively wide front baffle with a front mounted flared port. This does give the UniField One some tuning potential; if the bass is too overpowering in a very small room, stuff more Dacron up the front port and it should tame the bass beast.

The main driver is a coaxial design, sitting in a 172mm cast frame. It combines a silk-dome tweeter using a neodymium magnet with a transparent TPX mid-bass cone coupled with what the company defines as a ‘low distortion motor’. This UniField driver is actually based on a BBC design and von Schweikert licenses this from what used to be the corporation’s engineering research department. The drive unit itself looks very similar to a SEAS Prestige model, but even if it was an unmodified version of that unit, the raw materials are good… that’s an extremely expensive coaxial drive unit in its own, unmodified, right.

The company recommends the speakers sit on tall stands when used off wall, but the UK distributor goes one further and supplies a pair of Partington Super Dreadnought speaker stands, pre-filled with the appropriate mass for the loudspeaker. The stand is not overfilled, and this does give mean the stand has a dull ‘ring’ instead of a duller ‘thunk’ when given the knuckle test, but as the rest of the speaker package is deader than Elvis riding Shergar through a graveyard. The distributor also supplied a two-metre set of VSA Signature shotgunned (jacketed bi-wire cables, with eight different cables per jacket, recombined to single wire) speaker cables. These cost as much as the loudspeaker itself and they did offer a level of mid-band transparency more than commensurate with the loudspeaker itself. Certainly, in listening sessions through the UniField One, they proved themselves on a par with competitive cables from Atlas, Audience, Cardas and JPS.

With a claimed sensitivity of 87dB, a nominal impedance of eight ohms (with a six ohm minimum) and a power rating from anywhere between 20W-125W, the speakers should be an easy match with any amplifier. The key word there is ‘should’. For, although the UniField One is not a tough load (in measurement terms), it’s a demanding one in terms of quality of electronics. While notionally possible to be driven as some kind of ‘mullet’ system (where the cost of the loudspeakers far outweighs that of the source and amplifier), a more intelligent partnering should be considered, because the speakers are very transparent. I found a perfect set of partners in the Deltec pre and power amplifier combination also tested in this issue, and in a small room these drove the speakers with ease.

There are two parts to the auditioning, here. Aside from the usual ‘how does it sound’ section, there’s the bold claim that the loudspeakers are ‘universals’ to contend with too. This latter is easy… the UniField One lives up to the claim. Sort of. These speakers are best used firing straight down the room (as in, with minimal toe-in) and very slightly closer together than usual. In that setting, the speakers shine in a similar way to KEF coaxial designs, although these tend to prefer a wider than usual placement. You could apply that simple formula to big room and small and get a very similar result.

So why ‘sort of’, then? The speakers are somewhat influenced by their position in the listening room relative to the rear and side walls. Although there’s no ‘too far’ position, too close to the boundary and the bass begins to grow a boom. Filling in the port can mitigate this, but the speaker sounds at its most free with some air around it. A true universal design would have no placement issues, although I think such a speaker only exists in the virtual world. Certainly, this is one of the least room dependent conventional speakers on the market and achieves its claim (once again with KEF being in the same league).

So, what does it sound like otherwise? Surprisingly and accurately deep. No, it doesn’t ‘beef up’ the bass and it will need some reinforcement in really large rooms, but as a small room speaker it delivers pretty much all you need from the bottom end, in as clean a manner as you could ask for. This is why it’s heavy on the quality; any sense of mid-forward ‘detail’ or brightness in the electronics is laid bare here. Because it’s so honest, it demands the same from its partners, and such partners are rare.

It’s detailed and insightful without drawing attention to itself. Opera sounds like something more than a collection of vowels set to music. Rock has drive and energy and can be played at a fair lick. Jazz sounds close-knit and focused. Orchestral music has the energy and passion or it has the focus and precision needed to parse Beethoven at one end and Haydn at the other. It’s as happy as your room and your system will let it with anything from a solo voice to a massed choir. Which is remarkably hard to do properly.

There’s an obvious rival in the KEF Reference 201/2, also in this issue. Both sport a coincident drive unit (the famed Uni-Q, in the case of the KEF), both are standmounters and while the 201/2 is actually a three-way design, they have similar frequency response characteristics. A soundbyte comparison would place the KEF is the winner for those ruled by their heads, where the UniField One is the one from the heart, but as with any pithy comment, it fails to get the details across. The KEF is brighter and more ‘modern’ in its balance, and far more comfortable in a wider range of rooms, but the UniField One wins out in sheer musical naturalness. I’d struggle to choose one over the other because in fairness, comparing the two is almost an exercise in futility because their commonalities are more apparent than their differences, especially in terms of detail and soundstaging. This shows both companies are on the right track and even set against the home team’s best opposition, the UniField One has a lot of music to offer..

This is a very clever loudspeaker. It’s voiced to sound remarkably good, no matter what you throw at it. That’s not smoke and mirrors, just very attentive listening from an engineer who knows how to make a good sound. Using the right materials and the right components makes that easier to execute, but I dare say Albert Von Schweikert could make a good sound out of a loudspeaker made out of matchsticks and tissue paper given the UniField One.

SPECS & PRICING

Two-way standmount loudspeaker
Front firing reflex port
Main driver: coincident coaxial drive unit
Silk dome tweeter at acoustic centre
176mm TPX mid-bass driver
Sensitivity: 87dB
Nominal impedance: eight ohms (six ohms minimum)
Frequency response: 40Hz-22kHz
Power handling: 20W-125W (250W peak)
Dimensions (HxWxD): 36x23x33cm
Weight: 12.7kg
Price: £4,995 per pair

Manufactured by Von Schweikert Audio
www.vonschweikert.com

Distributed by Audioplay
www.audioplay.co.uk
+44(0) 207 359 6962

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