Avantgarde Acoustic Uno Series Two loudspeaker Page 3

I initially set up the Unos in the living room, just to give them some playing time until the arrival of Jim Smith, who had offered to come by for a visit to help carry the speakers upstairs to my listening room and check that they were working properly. The Uno is heavy (the subwoofer alone weighs 100 lbs) and awkward to get ahold of, so taking them up the narrow set of stairs to my listening room involved a certain amount of weeping, wailing, and gnashing of teeth.

Once in the listening room, they were placed in what is my more-or-less-standard position, along the long side of my 16' by 14' by 7.5' room, forming an angle of about 70 degrees from the listening position, toed-in to point almost exactly at the listening seat. The distance from the listening position to the midrange driver (the driver itself, not the front of the horn) was about 9.5'.

Jim Smith had brought along a 1/3-octave spectrum analyzer, which was useful in tweaking the subwoofer levels. My room has a closet with louvered doors on one side, which tends to create a L/R bass imbalance; the Uno's subwoofer's level and frequency controls were able to correct this to a considerable extent. Subwoofer phase is reversible by the simple expedient of reversing the subwoofer cable connections; I left the sub in phase with the midrange and tweeter. The horns' controlled dispersion (narrower than that of direct radiators) is supposed to make them less sensitive to room acoustics; this may be so, but a pair of RoomLenses placed to the outside of each speaker still resulted in a reduction of "room sound" and a wider soundstage.

The Uno's powered subwoofer allows the use of main amplifiers with much lower power; unfortunately, it also means that there are two more amplifiers in the system, with greater opportunity for ground loops. And, sure enough, when I first set up the speakers in my listening room, I got all sorts of buzzing and humming noises coming through the midrange horns and the subwoofers. In my experience, the only way to solve ground-related noise problems is to try different grounding and hookup arrangements (each piece of equipment grounded/ungrounded; preamp, power amp, and subwoofer amp plugged into the same outlet/different outlets) and hope that some combination works. The Uno's sensitivity is about 13-15dB higher than that of the average audiophile speaker (footnote 1), which means that noise as well as signal will be correspondingly higher. In any case, I was able to get ground-related noise down to an acceptably low level by grounding some of the equipment and letting the rest float.

Sound
One of the most thought-provoking articles to have appeared in Stereophile in recent years was Markus Sauer's "God Is In the Nuances" (Vol.23 Nos.1 and 2). Taking another run at the perennial problem of defining what it is exactly that we want from a music-reproduction system, Markus argued that the main reason people listen to music is to have an emotional experience. He presented experimental evidence (from a doctoral thesis by Jürgen Ackermann) to show that some audio components are markedly superior in their ability to produce an emotional response in the listener, and that this emotional response is a function of subtle factors in the reproduced music, factors that are difficult to identify by the sort of critical analysis normally performed by audiophiles and reviewers.

Markus' example was of the superiority of an analog/tube system over a digital/solid-state one in producing an emotional response to the music, but he might well have been talking about the Avantgarde Uno. There was something utterly compelling about this speaker's presentation of music, something that produced an emotional response in a way that rendered almost pointless the analysis of sonic attributes commonly used by audiophiles and audio reviewers. The Uno drew me into the music, focusing my attention on expressiveness in the playing and singing rather than on audiophile concerns like detail, soundstaging, tonal balance, etc.

Emotional response to music is a very personal matter. Listening to "Make Our Garden Grow," from Candide, played over a car radio affects me more profoundly than The Beastie Boys' Greatest Hits played over the world's best audio system (or live, for that matter). However, whatever kind of music you like—yes, even the Boys—my bet is that you'll find it more involving with the Avantgarde Uno.

If I were to attempt to analyze the Uno's appeal in audiophile terms, the obvious starting point would have to be dynamics. The Uno could play loud, very loud—and live music is sometimes very loud. Of course, given sufficient power, some conventional (ie, non-horn) speakers are capable of high sound-pressure levels, and speaker designers have started paying more attention to this attribute. (The Vienna Acoustics Mahler, which I reviewed in Vol.23 No.4, and the Paradigm Reference Studio/100 v.2, reviewed in Vol.23 No.6, are good examples of this trend.) However, the way the Uno presented high levels seemed qualitatively different. It wasn't just loud; it was effortlessly loud.

There's the obvious automotive analogy of 200hp from an 6-cylinder vs 200hp from a 4-cylinder engine. Even more apt is the comparison of a singer with a naturally big voice vs one with a smaller voice who is able to produce a big sound through sheer effort: Both singers can produce the same volume, but the one who doesn't have to "push" to get the effect is more pleasant to listen to. With the Uno, there was never any sense of "pushing," and no dynamic compression as things got louder.

Martin Colloms reported that the Avantgarde Duo has extremely low distortion; I expect the same will prove true of the Uno. The effect of this low distortion was an absence of volume-dependent strain, and I often found myself playing the system louder than is my custom. Played at realistic levels, Reference Recordings' Big Band Basie had a visceral impact, the combined weight of the brass filling the room with a power and punch that were simply breathtaking.

But the ability to produce high SPLs with low distortion was only part of the Uno's dynamic capability. The speaker was also able to project a great sense of quickness and dynamic tautness at moderate and low levels. The sound was very direct, as if the speaker was being driven directly by the signal, with no intervening electronics—an effect that may be related to the fact that there's no crossover between the amplifier and the midrange driver. In demos, there's a tendency to want to show off the speaker's ability to play loud, but the Uno doesn't have to be played loud to sound dynamic.



Footnote 1: The average audiophile speaker's sensitivity is 85-87dB, according to John Atkinson's article, "Measuring Loudspeakers Part 1," in Vol.21 No.11.
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