Meeting Gunny
AXPONA 2019 was my first exposure to Sonner Audio.  After strolling the long hotel hallways and listening to dozens of rectangular boxes playing jazz trio music, I was ready to give up and head home.  As I reached the corner near the elevators, I paused.  Here was Tchaikovsky’s “Pathetique” Symphony, with a realistic sense of scale and accurate timbres.  Maybe I’d stop for one more listen.
Gunny Surya, Sonner’s president, was running the exhibit.  It didn’t take long to understand that he has an abiding passion for classical music, with a well-stocked hard drive of the repertoire.  (Translation: not only does he like the music I do, but also he has many of the same performances.)

Outward appearances

Several aspects of the Sonner display immediately caught my attention.  First, the display was powered by a Luxman integrated amplifier – a worth component, but nothing extraordinary, either in performance or in price.  Gunny was able to produce excellent sound with electronics the average audiophile could afford.

The Allegro Unum speaker is a little over a foot tall and eight inches wide, with its front baffle slanted backward.  The enclosure is almost eighteen inches deep, but doesn’t draw the eye any more than the standard rectangular box when seen from the listening seat.  The speaker front is aluminum, and the rear is curved.  No exotic materials or bizarre geometric shapes draw attention from the music.

Along the same lines, the driver component is intelligent but not aggressively high-tech: there’s a one-inch ring radiator tweeter, and a six-inch magnesium tweeter.  The crossover point is 2 kHz.  Transition slopes are not specified.  

Selecting such high quality but conventional components told me something about the designer.  For several days at AXPONA, I had been listening to ribbon or air motion or diamond or beryllium tweeters mated to cone woofers.  These high-tech high frequency drivers often become marketing points, but they don’t necessarily merge with the low frequency elements: often there’s a striking, prominent treble and a slightly slower bass.  The result is sometimes far from coherent.

First Impressions

Gunny passed me his server pad.  Many manufacturers advertise their abiding love of music, but there are not many have as extensive a classical collection as I saw that day.  

I scrolled around and found Paita/Royal Philharmonic in the Mahler “Titan” symphony (Lodia 776).  This is a reading of uncommon sensitivity to tempo and delicacy, and no other conductor achieves the same effects.  The Allegros played with authority and grace.  

As the performance rolled along, I raised my left hand to shoulder height and began conducting.  Here I encountered the special charm of the Allegro Unum; it draws the listener into the music to a remarkable degree.  The score lies open on the podium, you can hear into the composer’s intention and the orchestra’s execution.  There are few speakers of any size or price that can accomplish the feat.  To produce this immersive experience with a modest system in a hotel room is most impressive.  
Gunny and I agreed that this was a speaker that needed reviewing.  I commented on the woofer dimension and the limitations it would place of bass performance and dynamics.
“You won’t be able to match a subwoofer to this speaker,” Gunny said.  “The speaker’s too quick, too articulate.”

I was happy enough to find a speaker of modest dimensions that did so well with everything above the low-40 Hz range I didn’t complain.  In the end, I was able to find a subwoofer to accommodate the Allegros, too.

 Home Trial

The Allegros arrived with twenty-six inch high, three-legged Sound Organization stands and spikes.  There’s a small rectangular panel that mounts on the front of the stands.  Wilson Audio used the same tactic to improve the bass on the original Wilson WATT.  This combination placed the tweeters at ear level.  The speakers are ported, and placing them closer than two feet to the rear wall boosted mid-bass, at the cost of some smoothness.  I found that the sound balance was better with the speaker out into the room.  Angling the cabinets in about 15 degrees sharpened the focus. 

My impressions at AXPONA were confirmed by listening at home.  The Allegro Unum is detailed without being irritating.  That’s intelligent design and driver selection at work.  It possesses a great sense of rhythm and allows the music to flow smoothly.  This is certainly a speaker you can listen to all evening with pleasure.  

The Allegro produces a very broad soundstage, and admirable depth.  In fact, there was little this speaker couldn’t do in a moderate sized room except produce lots of bass and thunderous dynamics.  

Plays Well With Others

The Allegros matched numerous components.  Every amplifier from an Audio Innovations Alto integrated (solid state, 35 watts) to a Wells Innamorata power amp (solid state, 150 watts) to Line Magnetic 210IA integrated (vacuum, 8 watts) to VAC Renaissance 70/70 power amp (vacuum, 70 watts) produced an enjoyable result – but each pairing resulted in a different sound.  I could easily discern each amplifier’s signature: not only were the characteristic sounds of tubes and transistors clearly portrayed, but also the differences between push-pull and single-ended circuits were shown.  
I swapped various interconnects and speaker cables into the system, and again the differences between solid and braided, copper and silver and hybrid designs showed up plainly.  But I never had an unsatisfactory listening session with the Allegros.  That’s unusual in my experience: a speaker that works well with one set of equipment produces marginal or even unacceptable sounds with another.  A simple example is the catastrophic mismatch between some horn loudspeakers and grainy solid-state amplification.  No such problems occurred with the Allegros.  And, as time went on, I appreciated Gunny’s choice of the Luxman integrated: it was clear and detailed with stepping over into the etched or aggressive side of reproduction.  

 Mating Game

There remained the problem that all small speakers must endure: they can’t go very deep into the bass, and they can’t produce the ultimate in dynamic range.  Gunny had said there were no subwoofers to match the Allegros.  Who was I to argue?

But high fidelity is a field that encourages experimentation, and sometimes rewards the listener with very pleasing results.  

I carried one Hsu VTF-2, a ported design, into my medium-size listening room and set the crossover to 30 hertz.  The combination added an octave of bass and impressive dynamics, but the midrange became a little thick and slow.  I adjusted crossover point, phase angle and output, but they combination never melded: the Hsu couldn’t keep up with the Allegros.  The Allegros weren’t too “fast” in the sense of sounding forward, but they played more clearly.

I don’t give up easily.  What could be better than a single, well-designed subwoofer?  Two, of course.  With a Hsu unit behind each Allegro, I had more than enough bass and lots of dynamics, but the presentation was still split between the Allegros and the subwoofers. 

In retrospect, the solution was simple.  I have a pair of MartinLogan Depth i subwoofers in my main system.  That was a good match: speed, control and extension complemented the Allegros very nicely.

While you probably wouldn’t go to that extreme, it’s worth noting that the Depth was designed to work with electrostatic main speakers.  I use them with my stacked Quad 57s, which are famous for their speed and coherence.

VII.  In Context

The Sonner Allegro Unum is a wonderful speaker.  It’s smooth and continuous from the low-40 hertz range to the limits of audibility, fits into small- to medium-size rooms without drawing attention to itself, and works with any amplification you can find.  It’s handsome in a way that most small rectangular boxes aren’t.  

The Allegro has better bass extension and definition, better dynamic range, and a smoother, more continuous voice than the crop of small monitors.  Placed in an appropriate room, I can’t think of a speaker this size I’d enjoy more.Ω 
Richard Weiner


-  In black or white: $9,900.  Speaker, stand and audio points: $11,890.

Product Details

Sonner Audio Reference Stand Mount loudspeaker - 2 way stand mount loudspeaker capable of delivering soundstage and size similar to the one produced by a floorstanding speaker. Delivering musical emotion with natural sound and vivid imaging within a huge soundstage.  Available in Gloss Black and White body. The face plate can be changed to different color or finish.


Sonner Audio
68 Daniel Webster Highway, Merrimack, NH 03054
(603) 881 3978