Simon Mears Audio Ucello 3-Way Horn Loudspeakers
Kick around in audio for long enough and sooner or later you twig that there are perhaps as many opinions about what sounds ‘right’ as there are models of pre-amplifiers, cartridges or any other component you care to name.
Of course, and quite naturally, few of us defer to anyone in this regard. Watch people at an audio show. If they don’t go from room to room vocalising their opinions, then you’ll know what they think anyway from watching their faces and their body language. Toe tapping from some – yet from others a grimace and a cold shoulder.
This stuff is deeply personal. No currently known science can reliably guide us to what will sound right or wrong, even though many audio manufacturers today would have us believe that measurements are everything.
Right there. See that? I betray my own bias for musicality, which puts me at odds with those in the community for whom a glimpse of an amplifier spec sheet with vanishingly low distortion figures and a formidable damping factor tells them all they need to know. “It’ll sound great.”
Me: “Um no, actually. It’s solid state so it’ll likely sound mechanical and bleached. I am right and you are wrong.”
Let’s pause, shall we?
And while we’re at it, can someone at the back there please close the door now that the sand-ophiles and measurebators have left the room in disgust? Thank you.
The rest of you pull up a chair and make yourselves comfortable. We’re going to take a look at some speakers – horn speakers, naturally – designed and built to be a marriage made in heaven with single ended triode amplification. Whether they are going to be a lasting union with the kit you have at home I can’t say. All I can do is tell you about how they are made and how they sound in my listening room with my system.
The designer and maker Simon Mears is a ‘wammer of long service. Threads on his DIY experimentation with Tannoy designs remain here on the ‘wam for your reading pleasure. Rich with detailed photographic record and notation at various stages in the construction and voicing of the projects, the threads testify not only to the thoughtful way Mears approached his home builds, but also to the extraordinary quality of his workmanship.
But Mears is a DIY builder no more. He has gone commercial, deciding to make his hobby his living. The Ucello three-way horn speakers are his first product as Simon Mears Audio.
Ucellos are not, by horn standards at least, particularly large. Designed to be living room friendly, each speaker stands 78cm (w) X 96cm (h) X 50cm (d). Unlike other contemporary horn speakers Ucellos are a single box all-in one configuration. They don’t make a design statement by treating each of the horns as a separate element.
The Ucello cabinets are built and finished to an exemplary standard that stands favourable comparison with that of top grade bespoke furniture and any other manufacturer of high-end speakers you care to name. The carcass is made from high grade 18mm and 24mm Baltic birch ply veneered in a choice of finishes. The review speakers, Mears’ pre-production and demo pair, were veneered in pale figured maple, with darker figured pear wood veneer contrasting nicely on the mouth of the bass cabinet, and finished in satin hard wax oil. Their predominantly pale colour helped to somehow minimise their visual impact in my listening room.
Nevertheless, their size is a trade-off. Horns able to load compression drivers through the 60- 1,000Hz range that most music covers can be fairly compact, but the laws of physics dictate that length must increase exponentially as frequency falls, so that to plumb the sub-30 Hz depths of concert piano or church organ a horn has to have a large mouth and be very long – that is long as in many metres. The practical, physical challenges this poses for speaker builders is why some favour hybrid arrangements with cone speakers in infinite baffle or ported boxes delivering the lower frequencies.
Mears is dismissive of this approach, observing that he’s never heard it work convincingly, able to keep up with the horns above. Hybrid bass goes low but is not clean, he says. The Ucello’s bass, purist in approach so horn-loaded, reaches down only as far as 56 Hz, so it does work fully in step with the midrange and tweeters in the same cabinet.
Mears was inspired to make the Ucellos by the Belle, a domestic speaker designed in the 70s by Paul Kilpsch. The Belle carried its tweeter above the mid horn, but in the Ucellos Mears has opted to put both on the same axis 80cm from the floor, tweeter to the outside, with the bass cabinet underneath.
Having over many years experimented with multiple types of loading horns, Mears believes that Tractrix profiles, executed in built-up plywood stacks that are then machined to smooth perfection, are the best performing option sonically. I have to say as a non-engineer that those on the Ucellos strike me as having a rather sexy ‘please stroke me’ appeal. The tweeter horns are circular when viewed from the front but those of the midrange drivers are horizontal ellipses in order to take up less space.
Mears’ has opted for compression drivers from the Italian vendor B&C which he says have a softer, smoother, more organic sound than many. The midrange is provided by a 2” throated unit with a composite diaphragm while the 1” tweeter is has a Mylar diaphragm. The woofer in each Ucello is a 15” cone driver by Eminence, backwards firing and loaded by a folded horn. The crossovers – there are two per Ucello – are fourth order designs executed with good quality components by ALK Engineering, a US company that specialises in horns. Internal wiring between speaker binding posts and crossovers, and from crossovers to drivers, is silver and copper, sourced from Audio Note. On the rear of each cabinet is a pair of solid brass rotary attenuation controls that enable customers to tune for room acoustics over a range of 18 dB (mid) and 12 dB (tweeter). The Ucellos present a constant eight Ohm impedance and have an efficiency of 104 dB.
Before the arrival of the Ucellos the only horns I had heard were in other peoples’ systems, and I’d found them interesting, but not arresting. They had the good manners not to be shrill or harsh, but neither had they blown me away with what I had been led to expect by way of you-are-there realism. Had the problem been the accompanying amplification? Possibly. The Ucellos though were a different animal altogether. My reaction to the first notes once we’d set the Ucellos in place and hooked them up made me jump with surprise.
Indeed. The Ucellos are that fast compared to cone drivers in ported or infinite baffle speakers that they require the listener to make a major recalibration of expectation. They also throw an alarmingly palpable audio image if he or she sits in the quite narrow sweet spot. Shift sideways because like me you find this artifice distracting, and while the image loses its focus the Ucellos’ tonal balance remains in equilibrium.
Compression drivers require brutally steep crossovers in order to avoid adjacent drivers singing along in dis-harmony. The design executed for Mears by ALK Engineering is successful; what I heard was clean and seamless, and I was surprised to find that it didn’t leave the Ucellos devoid of musicality like so many forth order crossover designs can. Could this be because the Ucellos are so fundamentally musical that they get away with it despite being dragged back by the necessarily steep crossover slope? Either way Mears and Klappenberger have hit upon a compromise that works, and very satisfyingly too.
Mears regards the 300B as the most musical of the power triodes and developed the Ucellos using primarily his own 300B SET amplifier as the driver. With their brass attenuator knobs set to the flat positions, the Ucellos are therefore voiced to make the most of classic 300B midrange warmth. I rolled four different 300Bs through my Kegons during the time I had the Ucellos – Psvane HiFi Series, Psvane 300B-N perforated plate, Shuguang 98 and Sophia Royal Princess/TJ 300B/se. The speakers weren’t able to make use of the extremely extended and powerful bottom end of the solid graphite plate Sophia/TJs, and in the midrange the two Psvane types with the Ucellos were rather ho-hum. My favourite was the good-old cheap-as-chips ’98 which brought a really beguiling luminosity and tonality to the party, even if it lacked the grunt of the Sophia/TJs, and the extended top end of the two Psvanes. Perhaps what this proves more than anything is not that I am a perverse old curmudgeon (although I undoubtedly am) but that the Ucellos are a particularly transparent transducer and that if owners make upstream changes in their system then they are undoubtedly going to hear the results rather plainly.
The Ucellos exhibit no sign of the cupping I’m told often bedevils horns and their ability to go from loud to soft is quite remarkable; they are among the most dynamic and sensitive transducers I have heard, able to portray micro dynamics such as the inrush of air over the teeth of a singer, then make you literally jump in astonishment with a loud and fast crescendo. These pyrotechnics are not initially impressive, and then ultimately irritating. They helped the Ucellos, driven by my 18 Watts per channel Audio Note Kegons, to deliver more musical you-are-thereness than pretty much any speaker I have heard in my system.
This judgement has to be delivered with a caveat: personally – and of course this is a personal, subjective judgement – I like more meat on my bones. Having lived since 2004 with Audio Note Es in my listening room I am used to hearing the fundamentals of pedal organ notes and the left hand of the grand piano. Es are not perfect either, but they are nonetheless speakers that swagger with musicality and full-fat, full range muscle. For me, the movement of air produced by full range speakers is as much a necessary part of the musical performance as the second and successive harmonics that pretty much all decent speakers should be able to produce.
However, the Ucellos were not designed to dig particularly deep and in that regard they are not only in quite a lot of exalted company, but they will undoubtedly be very satisfying indeed to music lovers who don’t share my particular prejudice. For those with a sufficiently accommodating listening space, an accompanying horn-loaded sub-woofer being developed by Mears should provide the missing bottom octaves without a loss of coherence.
Shortly before Mears and Tel arrived with the hired van to take the Ucellos away I decided to treat myself to a couple more sides of hornery before being forced to return to my faithful Audio Note Es. Although the range of the Ucellos suggests that they’d excel on intimate acoustic music – and indeed they do – I had found them extremely satisfying with orchestral material too, so I pulled from the shelf my ’67 Decca recording of Dvorak’s 2nd symphony with Kertesz conducting the LSO.
It’s not a mint copy – lovely gloss and no visible marks, but a frustrating level of groove pops and clicks despite multiple passes on a record cleaner. Nonetheless, I think it to be the finest and most uplifting reading of this wonderful work, written when Dvorak was just 24 year old. So on to the turntable it went.
Down with the arm lever.
‘Hello old friend.’
Whoa there! This was not the 2nd I’d been familiar with for so long. Through the Ucellos it had a new and startling immediacy and, strange to say this for a recording of a symphony orchestra, but an intimacy too – almost as if I’d been given a front row seat just behind the conductor with the players close by and fanned out either side. The harmonic density of the scherzo – which I’ve heard many speakers struggle with – was handled by the Ucellos with aplomb, each musical layer distinct but flowing coherently, and the finale with its pulsing, hard driving rhythm had me smiling in recognition at the observation made by many that there is truly little new in today’s music. Rock and roll? Pah!
Even on their own, without the coming subwoofer, what the Ucellos do is truly addictive. Having lived with them for a while I am not in the least bit surprised that Mears has already taken orders for six pairs.
The buyers, in my view, have good ears. The Ucellos are a remarkable product by a clever and thoughtful manufacturer.
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