Avantgarde Acoustic Uno Nano loudspeaker
Could the Uno be made smaller and still retain its high sensitivity, unrestrained dynamics, and the sonic attributes that create the sense of "aliveness" that characterizes this speaker? This was the daunting task that Avantgarde designer Matthias Ruff and his associates set for themselves.
Although considerably smaller than the Uno, the Uno Nano ($16,500/pair) is still a substantial floorstanding speaker, no Honey-I-Shrunk-the-Uno miniaturebut its visual impact is more modest, drawing less attention to itself. The most immediately obvious changes from the Uno are the smaller midrange horn (Uno, 22.2"; Nano, 19.7"), and a tweeter horn that's integrated into the structure of the woofer cabinet, so that it doesn't add to the Nano's overall height, and permits a lower placement of the midrange horn. The Nano is 50" tall vs the Uno's 58", and 25.5" deep vs the Uno's 28". The Nano's weight of 157 lbs, including the SUB225-N woofer, is nearly identical to the Uno's. The Nano is an attractive speakerthe midrange and tweeter horns of the review samples were finished in a striking red metallicbut it doesn't have the Uno's "look at me" appearance of modern sculpture.
The structural changes are only the beginning. The Nano's midrange horn is smaller than the Uno's, but its M1-N midrange driver is larger (5.1" vs 3.9"), with a double ferrite magnet and a specialized 2.9" dome, especially developed for the Nano and optimized for large linear movement. The crossover from midrange to tweeter is achieved with a small chamber between the throat of the horn and the driver diaphragm, providing a kind of mechanical crossover, and allowing the midrange driver to be driven directly by the amplifier without any passive electrical components. This also controls the dispersion pattern, and is referred to by Avantgarde as the Controlled Dispersion Characteristic (CDC).
Because of changes in midrange and tweeter construction, the Nano's midrange/tweeter crossover is at 3kHz, compared to the Uno's 3.5kHz. The H1-N tweeter, derived from the same basic design as the Uno's, has been further refined; its specified sensitivity has increased from 100 to 104dB, with higher power handling. As with the midrange horn, the Nano's 5.1" tweeter horn is smaller than the Uno's 7" device.
As its name indicates, the Nano's SUB225-N active woofer is derivative of the Uno's SUB225, which itself had been improved for the Uno 3.0, and, like the SUB225, has two 10" woofers, now driven by a substantially revised 250W amplifier. The cabinet has the same 11.7" width as the SUB225's, but it's taller and not as deep; the subs' internal volumes are similar. The amplifier has both a speaker-level input (which Avantgarde recommends, and which I used), as well as an XLR line-level input. To minimize hum and/or noise caused by ground loops, the amplifier uses a transformer at the input; if ground-related noise persists, you can change the position of a "ground mode jumper" in the amplifier module. This involves opening the woofer enclosure by removing six screws. The manual warns that these screws must be replaced with great care, possibly using additional rubber/foam sealing tape, to ensure that the enclosure is completely airtight. Not the most user-friendly method, I'd say. Fortunately, I had no ground-loop problem, so I didn't have to tackle this task.
The woofer module has a set of crossover controls that allow the user to optimize the blend of the outputs of the sub and the midrange horn, and adjust the woofer volume to match the room acoustics and personal taste. In addition to a switchable filter that limits the sub's LF extension to 20, 30, or 40Hz (I used 20Hz), the amplifier module is also equipped with what Avantgarde calls Intelligent Subsonic Filter Circuitry. This monitors the woofer output and automatically shifts the high-pass filter to as high as 80Hz, depending on the volume and low-frequency content, enhancing dynamic headroom and protecting the SUB225-N from being overdriven.
When I first heard about the Nano, I assumed that, because it was smaller than the Uno, its sensitivity would be lower: after all, in most lines of box speakers, the smaller the speaker, the lower the sensitivity. The Uno's rated sensitivity was 100dB, but the Nano's is higher: 104dBnot a trivial difference. John Atkinson's measurement of the Uno's sensitivity in August 2000 showed that it was actually 102.5dB, higher than specified. I'll be interested to see how the Nano measures under the same conditions.
The review process for the Nano took much longer than is usually the casenot because of any problem with the speakers, but with Avantgarde's North American distribution. Stereophile's review policy is that a product given a full Equipment Report must be carried by at least five US dealers. Avantgarde changed its North American distributor about a year and a half ago, but when I began discussions with their new distributor about reviewing the speakers, I was told that although they'd lost some US dealers through the change of distributor, they still had more than five.
The review pair of Uno Nanos was shipped to me from Germany, and I set them up in a casual way, playing the speakers more or less just to break them in. However, as time went on, I heard through the audiophile grapevine that Avantgarde no longer had five US dealers; when this was confirmed, the review was put on hold. Finally, the word came from Avantgarde that they had a new distributor: Globe Audio Marketing, which also serves as distributor for some other prestigious product lines, including Audio Aero, Breuer, Brinkmann, and Nirvana. Before too long, Globe Audio confirmed that they'd acquired the requisite five US dealers. The review was on.
Not only was the review on, but Jody Hickson, Globe Audio's genial president and owner, lives in Stoney Creek, Ontario, only an hour's drive from my house. When he offered to help me tweak the Uno Nanos' positions, I happily took him up on the offer.
The Avantgarde Unofirst the Series 2.0, then the Series 3.0has been my reference loudspeaker since 2000, so I was generally familiar with the setup procedure for this type of speaker. Setting up the Nanos, however, was different. The woofer's crossover settings are now adjusted with three controls, not two dials. One dial still controls volume and the other the frequency range, but the range over which the latter acts is now determined by a new three-position switch (Low, Medium, High). Setting the frequency control wasn't that difficult, but adjusting the volume control required a delicate touch to get just the right amount of bass.
The Nanos were set up in roughly the same positions as the Unos: along the long side of my 16' by 14' by 7.5' listening room, the rear of the woofer module about 18" from the front wall, the angle between the speakers and the listening seat a bit wider than classic 60°. The speakers were toed-in so that the midrange driver and tweeter pointed about 8" to the sides of the listening position. The Nano comes with feet designed to be easy on floors, but, for optimal performance, Avantgarde recommends using the supplied spikes under the subwoofers. I followed this recommendation in the final positioning. The speakers needed to be tilted back to produce the high soundstage I like, and, fortunately, Jody Hickson had brought along some extra-long spikes to accomplish the right degree of tilt.
For power amplifiers I variously used the PS Audio C-100, PrimaLuna ProLogue Seven (with ProLogue Three preamplifier), and Audiopax Eighty-Eight Mk.II monoblocks (with Convergent Audio Technology SL-1 Ultimate preamp). They all worked well, bringing out different aspects of the Nano's performance, but my overall preference was for the CAT-Audiopax combo, which had the best combination of transparency and musicality. This is what I used for most of my listening, and all of my comments about the Nano's sound assume that pairing. In the past, I've occasionally had a problem with hum caused by ground loops, and a speaker whose sensitivity is 104dB will let you hear the slightest amount of hum or other noise coming from the amplifier. This time, all was pretty quietuntil music started playing, of course! The little buzz I'd been used to hearing from the Unos' subwoofers between tracks of a CD was very nearly goneI had to put my ears close to the Nano subs to hear it.
In evaluating the sound of loudspeakers, the temptation is to focus on specific aspects of performance: lows, midrange, highs, transients, dynamics, soundstaging, etc. This is all very well, but my feeling is that doing this sort of analysis puts you in danger of missing the forest for the trees. The real question is a more global one: Assuming an appropriate source and amplification, does the sound produced by the speakers bear a close resemblance to live music? Does it sound as if the performers could be playing and/or singing in your listening roomor as if you're in a concert hall or other performing venue, listening to live music? This, to me, is the prime test of a loudspeaker.
The Nano passed it with flying colors. Something about this speaker transcended such technical aspects as frequency response, phase response, and dispersion, and allowed it to create an unusually effective impression of music being played live. This was apparent not only when I listened from the sweet spot, but from outside the listening room altogether. As I write this on a laptop in the living room, Something Wonderful: Bryn Terfel Sings Rodgers & Hammerstein (CD, Deutsche Grammophon 449 163-2), one of my "Records To Die For" picks of a few years ago, is playing through the Nanos upstairs in the listening room. Reason tells me that it's just a record, yet from time to time I find myself startledfor a few moments, at least, it sounds as if the gifted bass-baritone is singing upstairs.
Each summer, my wife and I attend performances at the Stratford Shakespeare Festival, a classical repertory theater in Stratford, Ontario. Among the Festival's incidental pleasures are the fanfares played at the Festival Theater prior to each performance, signaling the audience that the performance is about to begin. The fanfares, written by Louis Applebaum especially for the festival, are played by a small ensemble of four herald trumpets (three soprano, one bass) and a snare drum. The players assemble quietly against the wall in the lobby; you don't realize they're there unless you happen to look in their direction. They then start playing, and Wham!heard at close range, those horns have an impact that's purely visceral. I remember thinking, the first time I heard them, "Boy, I wish I had speakers that could reproduce a sound like that!"