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Reviewer: Paul Candy
Source: Eastern Electric Minimax CD player, Audio Zone DAC-1 non-oversampling DAC [in for review], Pro-Ject RPM 5 turntable w/Ortofon Rondo Blue cartridge
Preamp/Integrated: Manley Labs Shrimp, Audio Zone AMP-1, Pro-Ject Tube Box phono stage, Audio Zone PRE-T1 [in for review]
Amp: Manley Labs Mahi monoblocks, Audio Zone AMP-2 monoblocks [in for review]
Speakers: Green Mountain Audio Callisto (on sand filled Skylan stands), JM Reynaud Twin Signature [in for review], Silverline Audio Prelude [in for review], REL Q108 Mk II subwoofer
Cables: DH Labs Revelation, Air Matrix, Acoustic Zen Silver Reference interconnects, Auditorium 23 speaker cables, DH Labs D-75 digital cable
Power Cords: GutWire Power Clef², C Clef, X Clef² [in for review], Audience Powerchord
Stands: Premier three-tier, filled with sand
Powerline conditioning: BPT Pure Power Center w/Wattgate 381 outlets w/ Bybee Quantum Purifiers and ERS cloth
Sundry accessories: Grado SR-60 headphones, Pro-Ject Speed Box, Gingko Audio Cloud 11 platform, Skylan damping boards [in for review], Grand Prix Audio APEX footers, Isoclean fuses, Walker Audio SST contact enhancer, Nanotech Intron 8500 CD fluid, Audio Magic/Quantum Physics Noise Disruptors, GutWire SoundPads, Herbie's Way Excellent Turntable Mat, dedicated AC line with Wattgate 381 outlet, Echo Busters acoustic room treatments
Room size: 11' x 18' x 8', short wall setup, hardwood floors with large area rug
Review Component Retail: $3,695/pr

I remember the first time I heard a horn loudspeaker. I hated it. I thought it was the worst speaker I'd ever heard. There was no bass or treble. There was little in the way of precise imaging, soundstaging or any of the standard qualities one expects of a high-end design. Furthermore, I could hear a cupped-hands sort-of-boxy coloration. Those speakers sounded - well, horny if you catch my drift. Out of control. I listened casually over a couple of hours and then suddenly, somehow, those aforementioned colorations didn't offend as much. Music became curiously more real and visceral. I could feel the music in my chest. The resonant nature of pianos and violins was more life-like. What happened? It turns out that horn- loaded speakers, while hardly perfect, offer a totally different yet completely valid listening experience that may startle those raised on conventional dynamic speakers. They may even sound hopelessly broken. Sure, the lack of extension at both ends of the spectrum plus judicious coloration levels are caveats - to some even fatal flaws. However, give your ear/brain a chance to adjust and you might go ecstatic over their direct and very communicative mien, their immediacy, presence and coherence. You just might forget fussing over traditional audiophile minutiae and instead re-explore your existing record collection and perhaps even expand into other music genres.

Enter the Montreal-based Gemme Audio Concerti 108, a modern high-tech variation of the venerable rear-horn loaded loudspeaker.

Since Gemme Audio is a relatively new entry onto the audio scene, the company's Robert Gaboury provided me with plenty of background material. Considering that Robert was so forthcoming and enthusiastic (I wish all manufacturers were this helpful), I thought it best to condense our email exchanges into a quasi interview. Occasionally -- as in the case of Robert or Green Mountain Audio's Roy Johnson -- someone has truly poured their heart and soul into their product and it seems only fitting to share this whenever possible. I think you will agree that Robert has the passion when you read his comments. Cue interview:

Since I'm not familiar with Gemme nor are our readers, could you provide some background history as well as a description of the Concerti?

The Concertis are full-range back-loaded hornspeakers driven by a single FE108EZ 4-inch (actually, 2 5/8 inch) driver. They are CNC machined out of machine-grade MDF sheets and heat-pressed with heat-activated urethane glue to form a solid block.

The inside panels and horn path are then sealed and lacquered with polyester-based lacquer. When the insides are finished, everything is assembled, re-finished and "cooked" again to provide a complete enclosure hard as rock (and almost as heavy). The driver is mounted on a birch plywood plate finished with a compound called Effecta Gomma (a form of rubber coating).

The whole enclosure sits on machined leveling feet. Connectors are Cardas OFC
copper, inside wiring is 14AWG OFC copper. The compression chamber damping uses 95% pure untreated compressed wool.

My speaker design career started in a destructive way. I carried out my first speaker project at the age of 8 by destroying a portable AM radio I got for Christmas. Later on, I destroyed (and reconstructed) my mom's Telefunken table radio, then my father's cherished Grundig console. After those first projects, it was made clear that if I wanted to experiment more, it would be with my own allowance money. In Canada, the only readily available drivers then were Philips and Radio Shack so during the next 8 years or so, I bought every one of them.

I got into art school at 16 and at that time, all students were either members of a band, groupies or roadies. I was the tech guy, building horn enclosures for bands and friends. We had no money to get real JBL and Altec drivers, hence settled on Peavy and Celestion drivers. My first love was a JBL scoop. To me, the scoop was the most beautiful enclosure ever. No enclosure to speak of, just a set of panels and curves giving an absolute kick. Nothing can approach the sound of a full horn setup. Later on, I experimented a lot with both horns and really small drivers (and enclosures) such as the Philips 4060, which -- apart from the 9710 full range -- was the best-sounding driver.

So I like horns for their dynamics but I also enjoy sealed and reflex and TL enclosures. There is no perfect speaker just as there are no perfect dogs. I like German Shepherds and Bouvier de Flandres and Boxers and Labradors. My favorite instrument is piano, especially the concert grand. When I was younger, punch and dynamics were my top priorities. When I got older, I became hooked on harmonics, especially large pianos and room harmonics. Blind people never hit walls. They don't see walls, they
hear walls. That's fascinating. Being able to hear walls and boundaries also became an obsession.

I became aware of Fostex drivers a few years back. I was not interested in the full range aspect of those drivers but only in the specs, which made making small scoops or back-loaded horns possible: low Qs, rising response, low mass cones and powerful magnets. These enabled me to build scoop-type enclosures that would fit in a room. But I also discovered that full-range sound meant absolute integrity of harmonics. Now that was interesting: mixing horn dynamics with real harmonic coherence meant that one small enclosure could bring together the two single items that really mattered to me. It also means that you can "hear walls" on well-recorded live music.

We are constantly fiddling with the design of the Concerti. The product core is where we want it to be but the details are still being worked on. For instance, all new Concerti (v2) will feature leather wrapping inside the horn mouth to kill any HF content that might still be present in the path. Also, we are still working on the resonant aspect of the enclosure. Concerti v3 might (or might not) feature slot openings on the mouth's sides to equalize the high mouth pressure with the low room pressure, designed after gun silencers. We are also working on advanced composite construction using MDF, steel panels and leather. Lots of fun!

I met my business partner last year. I sold him one horn I built. He was impressed with the sound and was interested in selling the same speakers to others. I was not interested in building any more of those. I'm not a cabinet maker. I sold him the horn because I did not like the sound anyway (it was based on a Fostex FE168EZ, a nice driver but too directive and "hard" for my tastes). But I stressed the point that I was working on another, better design that could be CNC-built: the Concerti.

So we built prototypes, then CNC'd prototypes and thus the Concerti was born. It was a difficult birth. MDF is the best material to cut on CNC equipment. It's also the worst material to build horns with. Horns are resonant enclosures. Playing with resonant enclosures is like dealing with the devil. There is a Mr. Hyde/Dr. Jekyll thing to horns and resonant enclosures. So we had to find ways to alter the MDF's damping. The answer was to use polyester lacquer on all inside curves. Polyester is used on pianos, it's hard as glass (and also breaks like glass if hit hard enough) and transformed the MDF into something that was perfect for the design. It does not swallow energy like raw MDF.

The four-inch Fostex FE108EZ is an amazing driver. Not as directive as the bigger siblings, it has marvelous midrange, a nice top end and gives credible acoustic bass, which is kind of spectacular considering the small 2.5 inch cone surface. It's slightly directive, so first reflections are reduced, improving focus in smaller spaces.

Gemme Audio is not a one-product company. I like the Concerti for its ability to deal with ambiance and detail in smaller rooms. I also know that there are other avenues. One thing is
certain though - all future Gemme products will focus on harmonics integrity, meaning no crossover in the 500 - 5000Hz range. In the works are other designs: a three-way full horn speaker code named The Beauty and The Beast, aimed at larger spaces; a bass module -- the Basso -- designed to enhance all single-driver horn speakers (such as Concerti, Hornshoppe, Lamhorn, Lowther cabinets) based on a critically damped sealed design; various "conventional" ported enclosures using small extended range drivers etc.

I forgot to mention an important part of the Concerti/Gemme Audio story, namely my business partner Jean-Pierre Boudreau. Jean-Pierre is an obsessive-compulsive audiophile who will spend countless hours mounting and dismounting drivers, tweaking and re-tweaking cables, damping - every minute detail is tested and retested. He's the one comparing 100% wool felt to 85% wool felt.

My part often stops with the rough outline, the basic design where I get things where I want them. Jean-Pierre then takes over and tests everything on all kinds of equipment (chip amps, solid state, tubes of all varieties, different CD players, etc.). He tries to get a hold of the best possible way to integrate our products in the audio chain.

The Concerti pair you have is wired with a special cable made out of single-strand copper, silver and gold conductors courtesy of Jean-Pierre and his friends from 6 Sons Audio. To put it in hockey terms, I get the puck out of the corner while JP gets it in the net.

We also work with other players, namely from the Montreal Audiophile Association, a very active bunch of guys who love to test new ideas and products just for the fun of discovering things (good and bad). The Concerti were also tested and commented on by the chief sound engineer of Fidelio Records and by Stephen Monte of NAT Distribution.

The biggest challenge in building the Concerti (and all upcoming Gemme Audio products) was to find the right people to build it. We changed woodworking shops three times before finding the right CNC shop to cut the parts, the right craftsman to assemble the parts, the right paint shop to get perfect finish, the right machine shop to machine steel and brass and aluminum parts, the right finisher for chrome and zinc plating and buffing. When we decided to finish the horn with leather, we had to find the right "maroquinnier" and so on.

After all those headaches, we finally found the properly dedicated, quality oriented bunch of
artisans. That was the hardest part. Today we have assembled the perfect team to tackle any project. I guess that's what Gemme is all about. Sure it's about sound. Sound is the core of Gemme. But after we get the right sound, we have to think about the home into which it will fit.

Each and every pair of the Concerti is built by hand. One at a time. We decided not to produce offshore (the same lacquered cabinet would cost 75% less if produced in China) because having container loads of cabinets would restrict us with real-world applications: the person buying the Concerti. All Gemme Audio clients are unique. We want our products to be perfectly adapted to each client. For example, one Toronto client requested a special Raspberry Red (which we call Saturn Red, Saturn being the client's first name) with black leather interior.

Another client requested a very rare and hard-to-find Tiger-figured Anigre veneer. We basically had to wait for the right tree to fall in order to comply. All Gemme Audio products can be "hot-rodded" for any application. Inside wiring can be customized in any alloy or alloy combinations. So the corporate focus is working with clients once they've decided that the sound we offer suits them - to get exactly the right product variations. If someone requests a water buffalo wrapped enclosure (as someone did ask for), we get our maroquinnier on the assignment. Call it extreme WAF.

Could you tell me a bit more about the Fostex driver? Why the shape and patterns on the cone, dust cap and surrounds?

The FE108EZ Fostex is part of the Sigma series. It's a wonderful piece of engineering and I guess it's one of those examples where art meets science. The design of the cone and dustcap is called hyperbolic paraboloid. The surround (as well as spider) is formed in a UDR pattern, which means up/down roll.

Very simply, the cone and dustcap are creased for increased rigidity for a given mass. A creased piece of paper is more rigid than a straight piece of paper. So for the same rigidity, it can be made with thinner material. The paper material (actually banana pulp) is so thin that it's translucent.

For instance, if we compare the moving mass (including air) of the FE108EZ vs. the highly respected ScanSpeak Revelator 5-incher, the FE108EZ mass is 2.7 grams while the Revelator is 13.0 (this is for comparative purposes only since the Revelator cone is a bit larger). This means that the lighter cone has less inertia so it should be "faster" or easier to move.

A lighter cone also makes possible the use of a smaller voice coil. The 108's voice coil is 20mm while the Revelator's is 38mm. This in turn means less copper on the voice coil, hence a smaller inductance value (a high value inductance makes the coil acts as a low pass filter). The Revelator has a voice coil inductance of 0.35mH while the 108 clocks in almost 10 times lower, at 0.038mH. So a light moving mass coupled with a low inductance means a driver with high efficiency and very extended bandwidth.

Since there is no free lunch, there's a downside to this too: low mass means high resonant frequency and short voice coil means no extension to speak of. The Revelator has an Fr of 30Hz (!) while the 108 hits its excitation at 77Hz. The Revelator has a max extension of 9mm (each way) while the 108 gets an (almost) non-existent 0.28 mm. This means that the Fostex FE108EZ can't make any bass in a conventional cabinet while the Revelator is a bass freak.

In order to get
some bass output, the Sigma (as well as all Sigma models and most Fostex drivers in general) needs to be loaded by a horn enclosure. Fortunately, it was designed for such use (low mass and low inductance equal rising frequency response and no bass). The speaker is loaded into a very small sub-enclosure (less than half a liter), the compression chamber. The air trapped inside the compression chamber is - well, highly compressed. This compressed air naturally wants to decompress so it acts on the horn path's volume of air. The volume is increasing at an almost exponential rate so a small volume of air molecules (present in the throat at the beginning of the horn) acts on a slightly larger volume and so on until the horn reaches its end: the mouth. So a very small volume acts progressively on a large volume/area. Contrary to a reflex port where the air velocity can approach speed of sound to create port noise or chaffing, the horn decreases air velocity by acting as a gradual impedance transformer.

Technically, the Concerti is a horn/transmission line hybrid whose horn length is calculated as a quarter wave enclosure tuned to 42Hz, the lowest fundamental of the double bas. It behaves like a horn and a transmission line. In pure horn fashion, the enclosure would need to be 10 times as big. I do not want to imply that the Concerti will reach 42Hz flat but there is some output at that frequency, enough to give a credible image of the double bass.

Acoustic design is full of contradictions like the previous Revelator/Sigma comparison. On paper, it would be much simpler and more effective to stick a Revelator in a box and produce far more bass from a far smaller cabinet. I'm a piano freak and in acoustic music, bass is only part of the equation. The real thing is harmonics integrity, meaning the ability of a single small driver to reproduce the sound of fundamentals
and their harmonics in a pure and coherent way with no crossover reconstruction. I guess it's like concentrated orange juice versus freshly squeezed orange juice. Same 100% pure juice but different taste.

Speaking of contradictions, the same reverse psychology took place when I designed the Basso (the bass cabinet companion of the Concerti). Conventional wisdom would dictate the use of a high Q driver (one with ample bump at its resonant frequency) in a large box to achieve a max-flat alignment. Instead of this, we use a low Q driver (below 0.25) in a critically damped enclosure. Just to give some proportions to this, figure a 10" driver in an 8" cube. Using a critically damped design (meaning a box with a larger volume of air than what would be required for a max-flat alignment) gave us just enough volume to fit the driver and amplifier in a one cubic foot box and still get in-room extension to 15Hz with no boominess, just ultra fast transients.

I'm starting to drift here so sorry about the "loss of focus".

I noticed on other Concerti pics a metal ring around the driver. My sample does not sport one. I'm just wondering about the significance of that. I also noted that my driver is mounted on a suspended plate whereas others seem to be mounted directly to the front baffle.

The brass ring is a factory option. When we first introduced the Concerti, retail price was $4,700US (we thought the price was right because it was in the Cain & Cain bracket for a similar speaker, the IM-BEN with 108 driver). Stephen Monte from NAT Distribution, our US distributor, thought the American market would not be receptive to such a small speaker at that price so we had to cut costs somewhere to get the retail to $3,700.

There was no way we could drop the price without changing the basic design of a perfectly smooth horn path. So the ring had to go along with profit. But ring removal had to be compensated for with a beefier baffle board. So the baffle was redesigned using a full 1-inch plate (the suspended plate was 5/8th of an inch). There was no adverse effect on the sound and the ring is still offered as an option. That's why the new base-level Concerti doesn't have the ring. Overall I feel that this change was for the better since we can now offer full veneer as a cost-effective albeit cosmetic option.

Does the listed retail price include choice of finish colors etc? Or is there a surcharge?

For the basic retail of $3,700, black piano finish is standard as are cherry, maple and mahogany veneers. Every color you can think of is available. For piano finish colors outside black, there is a $300 surcharge. For regular 30% gloss lacquer, any color can be specified at no extra cost (even metallic colors such as silver and gold apply). Super exotic finishes are also available such as Bubinga, Ebony, Anigre, Zebrano etc. and billed at cost. We do not use veneers from endangered wood species. Exotic woods are bred.

Regarding the piano finish, it's
very important to understand that we do not use automotive finishes (i.e. a mat base coat topped with a gloss clear coat). A real piano finish has 7 coats of 90% reflective lacquer and each layer is hand buffed. It's very time consuming but it won't crack after a couple of years like automotive finishes will on wood.

The basic Concerti design evolved since the time you had your review pair and it will continue to evolve. For instance, all current production Concerti feature pebble grain leather in the mouth area on top of the polyester seal (this reduces micro turbulences by creating an air cushion around the surface pretty much like a golf ball). In the near future, the horn's mouth area will be stiffened with composite steel/silicone plates as requested by Fidelio Records' chief sound engineer. Connector plates will be thicker and silver/gold/copper wiring (the same as you have) will be standard. There's a lot of tweaking that will be done to extract the maximum transparency that the driver can achieve and I anxiously await your review for further tweaking suggestions.

These days I'm playing with an upcoming Gemme product code named TTMO with a minimum efficiency of 101dB (we're aiming for 104). This design relies on a super low-Q 12-incher (stiffer than anything from Lowther, AER and Fostex) fitted in a BLH enclosure that should exceed the 125dB dynamic range. Lot's of fun!