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Avantgarde Acoustics Trio/Basshorn Loudspeaker System

As you already know if you’ve read my review of the Avantgarde Acoustics Zero-1 Pro and Magico Ultimate 3 loudspeakers in Issues 245 and online, respectively, the horn-loaded loudspeaker is my little girl with a curl. When a horn speaker is good, there is nothing else that can beat it for dynamic speed and impact, low-level resolution, lifelike midrange presence, and sheer acoustical output. When it’s bad, well, horrid is not too strong a word for twelve-foot-wide instruments and voices, marked cupped-hands colorations, piercing treble, and audible discontinuity among drivers.

I’ve gone over the reasons for the horn’s strengths and weaknesses before in these pages, and I hate to put you through this same litany again. But on the off chance that some of you don’t hang on every word I write, I’ve prepared a condensed version to refresh your memories. (Readers who don’t want to suffer this ordeal again feel free to skip ahead about five paragraphs.)

On the plus side, first and foremost, is a horn’s ability to couple the sound it produces to the air of a room with far greater efficiency than any other kind of transducer. Like a megaphone (in fact, exactly like a megaphone), a horn constricts the area and volume of air that the driver attached to it works “into.” As a result of this constriction, the acoustic impedance of the air trapped in the horn’s throat—the narrowest part of the horn immediately in front of the driver—comes much closer to the high acoustic impedance of the driver’s featherweight diaphragm. This superior impedance matching allows that diaphragm to generate very high sound pressures from very small excursions. (Indeed, within its passband a horn-loaded driver’s diaphragm barely has to move, greatly reducing inertia and thereby increasing the speed with which it starts and stops, while also virtually eliminating its backwave—and the necessity of damping, venting, trapping, or otherwise coping with same.)

Moreover, as the horn’s tapered shape gradually increases in area toward its mouth—the widest part of the horn that opens onto the listening room—the high-pressure soundwaves generated in the horn’s throat by those miniscule vibrations grow lower in pressure and progressively larger in displacement as they travel down the horn’s length, allowing them to couple more efficiently to the low-impedance air of the listening room. In sum, a horn-loaded driver is in many ways the ideal acoustical-energy delivery system, typically producing ten times more acoustic output than a cone speaker would from the same amplifier power via an ultra-lightweight driver that, because of its greatly reduced inertia, is capable of astonishing speed and resolution.

Unfortunately, a horn’s negative side is also built into it. To wit, the very-high-pressure soundwaves generated in the horn’s throat can reflect off the throat walls. These reflections (and any high-Q resonances in the drivers themselves) will add a characteristic turbulence to the signal, which ends up being amplified along with the music. The sonic result is the “cupped hands” or “horn coloration” typically heard with P.A. systems. Additionally, though properly designed horns are inherently phase-correct transducers, the necessarily much wider disposition of their drivers (because of the physical size of the tubes they are attached to) can make overall time/phase/frequency coherence a dicey proposition.

Nowhere is this incoherence more pronounced than in the bass, which in many contemporary horn systems is often handled by a cone subwoofer. Seamlessly matching a cone sub to an ultra-fast, ultra-clean, ultra-high-sensitivity horn via conventional means is about as tough a task as you can set for yourself in high-end audio. Even the best direct-radiating cone subs will seem slightly sluggish off the line compared to the super-charged engine of the horn-loaded drivers.

When it comes to horns, I know whereof I speak, because about two decades ago I spent several years trying to live with an elaborate horn-loaded system—the original Avantgarde Acoustic Trio-G2—before finally, and not without serious misgivings, giving up on it. For all its strengths (and it had a lot of strengths, many of them unique), the Trio’s weaknesses—particularly its horn colorations, its incoherence (primarily in the bass but also, from time to time, among its trio of horn-loaded drivers), and its subsequent failure to disappear as a sound source—finally compelled me to moved on to other transducers, even though, with the right recordings in the right octaves at the right levels, I never again heard certain instruments and ensembles, such as grand piano and symphony orchestra, reproduced with quite the same lifelike scale, power, and realism.

Until recently I thought that a horn’s minuses were simply uncorrectable adjuncts to its plusses. Then along came the Avantgarde Zero-1 Pro and the Magico Ultimate 3, and all that changed.

Avantgarde’s and Magico’s use of digital signal processing to correct for the inevitable time, phase, and impulse anomalies of a horn/sub system simply erased the phasey imaging, cupped-hands colorations, piercing treble, and driver-to-driver discontinuity that had worn me down and out some twenty-odd years ago. Thanks to DSP, both speakers now offered a top-to-bottom neutrality and octave-to-octave coherence that I’d never before heard from a horn-loaded transducer. Both speakers now disappeared as sound sources almost to the extent that well-designed cones or planars do. When these newfound virtues were coupled to the horn’s unrivaled transient speed, resolution, and acoustical power, you got a speaker that in most ways competed with (and in some ways bettered) the very best dynamic and planars around.

I put “in most ways” in italics because of this: For me Avantgarde and Magico’s amazing fix of a horn loudspeaker’s perennial ills brought with it a new issue (“problem” is too strong a word), though I grant it is an issue that won’t bother others as much as it does me.


I am an analog guy (as if you didn’t know), and both the Avantgarde Zero and the Magico Ultimate are digital loudspeakers, which is to say they digitally process all source signals that are fed to them, before turning those signals back to analog ahead of the amplifiers (built-in in the case of the Zeros, and supplied by you—all five pairs of them—in the case of the Ultimates). Now, to my admittedly prejudiced ear this A-to-D and D-to-A comes at a sonic cost. To put this plainly, sources (be they native zeros and ones, or analog waveforms turned into zeros and ones) sound, well, just a bit more digital—just the slightest bit “processed”—once they’re DSP’d. (For the exact opposite view, see REG’s review of the Lyngdorf Audio TDAI-2170 in this very issue.)

Frankly I heard this effect more clearly with the Ultimate 3 than with the Zero-1 Pro, as the thirty-times-more-expensive Magico is just that much more transparent-to-sources than the much-more-affordable Avantgarde. But to a degree it is there in both—a little bit of dynamic constraint, a little loss of dimensionality and air, a little rolling-off of the top treble, a little over-tightening of the bass. If you’re not addicted to analog warmth, bloom, and body (that “white magic” REG describes as pitiful self-delusion), you probably won’t care about these side effects. But if you are, and you’re wedded to horn loudspeakers, you’ll either have to live with them, which isn’t as hard to do as I might be making this sound, or keep searching for a horn speaker that doesn’t have ’em.

Which, oddly enough, brings me to the subject of this review—the all-new, enormously improved, all-analog Avantgarde Trio-G2/Basshorn system.

The new Trio-G2, like the old one I reviewed almost two decades ago in Fi magazine, is a classic horn loudspeaker, which is to say that there is no built-in digital correction of its drivers or their alignment. If you leave out the humongous stack of Basshorns that supplies low end below about 100Hz (we will come to this anon), in appearance the new Trio-G2 looks identical to the old one: three, progressively larger spherical horns (injection-molded from low-resonance ABS plastic) hanging from a spare but sturdy, lattice-like framework of steel supports, like a spray of three different-sized magnolia blossoms. Thanks to this flower-like look (and the multitude of colors the horns come in), the Avantgarde Trio was, is, and remains one of the most strikingly beautiful loudspeakers in the world.

However, though it appears to be the same loudspeaker that I reviewed nearly twenty years ago, it isn’t. In fact, almost everything about the Trio has changed, save for the ABS plastic used for its horns.

First, all three of the Trio-G2’s drivers are now higher in impedance. In the earliest version of the Trios, the tweeter, midrange, and woofer were 8 ohms. Now, the bass horn and tweeter are 16 ohms and the midrange 27 ohms, making for a 19-ohm speaker overall. This change in impedance not only makes it easier to use low-powered SETs to drive the Trio; it also allows for better damping by any amplifier. (Avantgarde claims that an amp’s grip on the voice coils is doubled.) Of course, higher impedances halve the power output of many transistor amplifiers (and some tube ones), but with a speaker that boasts the new Trio-G2’s 109dB sensitivity, you can give away a lot of power reserve and still have way more than enough juice to play back any kind of music at ear-splitting levels.

Second, the drivers themselves have been redesigned by Avantgarde’s Technical Director, motorcycle maven, and resident engineering genius, Matthias Ruff. The original bass horn used a paper-cone driver and a ferrite magnet. The current one uses a Kevlar diaphragm and a strontium-ferrite magnet. (The new Kevlar diaphragm features a big carbon-fiber dome on top to reshape the waveform so that it better mates with the horn’s throat.) The original Mylar midrange driver is now made of PEEK (polyether ketone thermoplastic), which is lighter than Mylar, resulting in a thinner diaphragm with the same stiffness and stability as the original. Its magnet has also been changed from ferrite to strontium. Finally, the compression-driver tweeter features a Mylar diaphragm (it had been aluminium), has a stronger ferrite magnet, and its voice coil is built to higher tolerances.

Third, the spherical horns have a new mounting mechanism. Where all three used to be directly attached to the drivers via bolts, they are now screwed on by means of a damping ring and a spring mechanism capable of extremely high pressure and an air-tight seal, rather like the lid on a jar of preserves. Damping the intersection of cone and horn is said to result in considerably lower resonance.

Fourth, the crossover has been adapted to the new higher-impedance drivers, and the crossover parts are of much higher quality. In addition, the dielectric material of every signal-bearing capacitor is polarized via a proprietary Avantgarde CPC circuit (capacitor polarization circuit). (When a signal changes polarity the dielectric material of a capacitor also changes polarity, resulting in dielectric polarization—a sort of slip/stick effect that creates a latency that can add time-domain distortion. The polarization voltage provided by the CPC circuit prevents these dielectrics from flipping polarity and producing this distortion.)

Fifth, the internal wiring has been changed. In the old Trio, all three drivers were driven from a single input. In the new Trio-G2, each driver has its own input terminals, allowing the speaker to be tri-wired or tri-amped. Of course, this also means that each driver has its own crossover board, so the signal no longer passes through the single board from which all three of the original Trio’s drivers were supplied. (The midrange driver sees only one capacitor in the signal path.) Additionally, in the first version of the loudspeaker Avantgarde used coaxial copper wire; today the wire is silver-plated copper.

However, the biggest change, quite literally, is this new Trio-G2 system’s low-bass driver.


In the original Trio, bass below 120Hz (the cut-off frequency of the Trio’s horn-loaded woofer) was supplied by a conventional, free-standing, cone subwoofer (or a pair of these per Trio), housed in a rectangular wooden box, powered by a built-in 60W solid-state amplifier, and crossed over via a built-in high-pass filter at slopes that were either 6dB or 12dB per octave—which one I can’t at the moment recall. (There is a very loud amusement park just outside my window.)

To say that this sub/amp/XO was the Trio’s foremost weakness is to put the case mildly. The truth is that any “subwoofer” that is called upon to play up into the power range (100–400Hz), as the Avantgarde’s was, is really acting more like a “mid/woofer” than a “subwoofer.” In other words, the sub didn’t go all that deep in its bottom range and played too markedly in its top one—its sluggish, comparatively ill-defined sound coloring, veiling, and “slowing up” the horn-loaded woofer’s fabulous articulation in the lower mids.

Back in the day, I tried just about everything I could think of to fix this problem, and though I could ameliorate it by adjustments to placement and crossover hinge-point, I could never eliminate it. This “overlap” of disparate sounds in the bass and power range, coupled with the way the horns occasionally called attention to themselves as individual drivers, was the main reason why the original Trio—for all its power, majesty, and resolution on much music—eventually wore me out.

I remember thinking at the time: “Why can’t Avantgarde build some kind of horn-loaded sub to fully match the speed, color, and detail of its horn-loaded woofer?” Of course, I already knew the intractable answer to that question: Size.

I’m not going to go into the math behind the design and construction of very-low-frequency horns because, frankly, I don’t understand it. But the long and short (actually, there is no short) of it is that to reproduce, say, a 30Hz note (which has a wavelength of 37.7 feet), a horn has to be roughly one-quarter that wavelength long (a little more than nine feet) and about one-third that wavelength wide at its mouth (a little more than twelve feet in diameter).

Obviously, a pair of nine-foot-long, twelve-foot-wide subwoofers is going to have what I would reckon to be a lowish wife-acceptance factor, not to mention room acceptance factor—you’d have to live in a palace to house such monsters. (Just for the record, if you wanted 20Hz response, a horn would have to be better than fourteen-feet long and nineteen feet wide at its mouth.)

However, there are ways around these problems, such as corner-loading or “folding” the horn within an enclosure. While corner or folded horns are still large, they are far more manageable in size (as any Klipsch owner can tell you) than a “true” low-bass horn.

Which leads me to Avantgarde’s solution to horn-loaded bass: what it calls the Basshorn, three pairs of which you see pictured between the Trio-G2s on p. 138.

Avantgarde’s Basshorns differ from the other legs of the Trio by not employing spherical horns attached to cone drivers; instead their twin, 12-inch, paper-cone woofers (with neodymium magnets) fire into a mix of exponential and spherical curves, 55 inches (four-and-a-half feet) in length and approximately one square meter (about nine square feet) in diameter per module. Their stacking structure produces a cylindrical wavefront with calculated low-frequency cutoffs of 55Hz for two Basshorns (which have a collective mouth area of about thirteen square feet), 38Hz for four Basshorns (which have a collective mouth area of 36 square feet), and 24Hz for six Basshorns (which have a collective mouth area of 54 square feet). All of the Basshorns are actively equalized below their cutoff frequencies to play down to 20Hz via a system, invented by Matthias Ruff, called ADRIC (Active Dynamic Radiation Impedance Compensation). Typically, the problems with horn-loaded drivers forced to work below their cutoff frequencies are caused by back reflections hitting the driver diaphragms, causing impedance changes and resonant peaks. Matthias has created an inverse curve to compensate for such changes and predictable resonances, which when applied allows the two 250W Class AB amplifiers that come with every Basshorn to see a stable, resonance-free load, and allows the listener to hear low bass without the usual blaring/farting noises of a horn eq’d below cutoff.

So, you may well be asking, what do all these changes add up to? The short answer is: The most lifelike conventional horn system I’ve yet heard in an actual listening room. Though the Trio/Basshorn system may not be quite as seamless, coherent, and colorlessly neutral as its beautifully DSP’d cousins, the Avantgarde Zero-1 Pro and the Magico Ultimate 3, it comes close, and does certain other things that I value better than either.


On the very first cut I listened to, “Guantanamera” from the superb Analogue Productions reissue of The Weavers Reunion at Carnegie Hall, 1963, the Trio-G2/Basshorns delivered extraordinary realism on Pete Seeger, Ronnie Gilbert, and Bernie Krause’s vocals, with no horn colorations, no sense of the speakers behaving as individual tubes or as tubes hooked to a “slow” subwoofer; in fact, virtually no sense of the speakers at all. Tone color was exceptionally rich and beautiful, as were the clarity of articulation and the delicacy of textures on voice and guitar. Imaging was neither razor-cut nor twelve-feet-wide; I’d call it “life-sized” (rather like a Maggie). In addition, on larger-scale numbers, such as the whole outfit chiming in full-throat on “’Round The World,” the spine-tingling thrill of fortes reproduced without shrillness or excess sibilance (okay, there was a slight touch of spittiness at the loudest moments) reminded me of why I fell in love with the original Trios in the first place. This was simply and wonderfully lifelike high fidelity, replete with a soundstage that extended wall-to-wall across a very large room and imaging that, as noted, was much more tightly focused and naturally sized than it used to be. Perhaps my only demurrer was that stage depth seemed somewhat compressed.

I had the exact same reaction to Marc Cohn’s “29 Ways” from MoFi’s reissue of Cohn’s eponymous album, where the Trio-G2/Basshorns were fabulous on kickdrum and Hammond organ, great (again) on voice, and extremely realistic overall. At louder level, the Avantgardes projected Cohn’s voice a bit forward of the plane of the speakers (as was the case with The Weavers), though, paradoxically, they also managed superior depth of stage with the backup singers on “Walking in Memphis.”

In timbre and dynamic, B.B. King and his band (from B.B. King Live in Memphis) sounded just as I’ve heard them in life. Indeed, it was listening to this harder-driving album, after the sonic triumphs of the first two, that made me realize that the density of tone color, depth of image, and dynamic ease I was hearing through the Trio-G2/Basshorn were qualitatively different than what I was getting from the Zero-1 Pros at home or the sound I’d heard from the Magico Ultimate 3s in Cali. The very slight sense of digital “processing”—of something very lightly curtailing the dimensionality and energy of music—was no longer present. No, the sound of the Trio-G2/Basshorn system wasn’t as textbook flat nor as time-and-phase-coherent (e.g., the slight touches of spittiness and midrange forwardness on fortes) as that of the digitally optimized horn systems, and, yes, I was listening to vinyl with the Trio-G2s rather than to server-based digital (as I did with the Zero-1 Pros and the Ultimate 3s), but despite any slight deviations from neutrality, the Avantgarde Trio-G2/Basshorn presentation was richer, airier, bloomier, and more robust than what I hear and heard from digitized horns.

After folk, pop, and blues, I turned to classical. If you think that the Trio-G2/Basshorn proved a letdown with large-scale acoustic music, you’d be very mistaken. On Malcolm Arnold’s Tam O’Shanter Overture from the excellent Classic Records reissue of Witches Brew (what a great-sounding LP!), I heard ravishingly lovely, massed string tone, superb timbre on brass and winds, great foundation on cellos and doublebasses, truly biting transients (without edge) on purling horns, darting flutes, and whip snaps, and deep rumbling timps. At the lovely entry of the Scots piping tune, I literally put down my pen, because there was nothing to critique—string and winds had the air they have in life, cushioned and sweet, and on orchestral tuttis the Trio-G2/Basshorns served up the terrific dynamic range that only horns are fully capable of. (At average-to-moderate levels I measured 38dBC valleys and 98dBC peaks—60dB dynamic range! And all of it clear and beautiful.)

This was a far cry from the sound I remembered from twenty years ago. The driver-to-driver discontinuity, which affected timbres, dynamics, and imaging, was gone, replaced by naturally gorgeous tone color, blur-free attacks, and lifelike focus, all accompanied by a realistic sense of ambient bloom. Plus, on full orchestra the Trio-G2/Basshorns were adding a sizable virtue I’d never before experienced from any two-channel stereo system.

I don’t know whether the centrally located Basshorns were the reason, but the new Trio-G2 had much of the solidity of three-channel playback, coming closer than any hi-fi I’ve heard to the continuous, wall-to-wall sweep of a real symphony orchestra playing all-out (rather than the slightly discontinuous, U-shaped, puddled-up-in-spotlights presentation that most loudspeakers deliver). In short, on symphonic music the overall presentation was spectacularly realistic.

Were there downsides? Yeah. Over and above the Trio-G2s’ occasional midband spittiness and forwardness, I suppose the Basshorns’ bottom end wasn’t as deep-going or as tightly defined as I’ve heard through certain other speakers, including the DSP’d horns, though the color, bloom, power, and natural sense of decay of these giant woofers were highly realistic. Avantgarde’s own claims notwithstanding, I estimate low-frequency rolloff begins at about 40–45Hz—not subterranean bass, but superbly continuous and very musical. Like most horns (including the DSP’d ones), the Trio-G2/Basshorn system had just a little less air in the very top treble than certain ribbons and cones, and once again was somewhat more compressed in stage depth than many dynamic multiways.

This said, what’s not to like? A horn system with top-to-bottom coherence, bloom, three-dimensional body, air, lifelike focus, and sensational stage width and continuousness, to go with the phenomenal dynamic range, lifelike speed of attack, and the superb resolution that such speakers have always excelled at delivering. A horn system with bass that (finally) matches the beauty, speed, and power of its midrange.

Of course, you’re going to need a good-sized room to house these critters (which is why they’re not sitting in my digs at this very moment). And only time will tell whether they’ll fully satisfy in the long term. But in the short term, after listening to scores of albums (and some digital, too), I can tell you that I haven’t heard a better (non-digitized) horn loudspeaker at anywhere near this price. (When you consider that the entire Avantgarde system—Trio-G2s and six powered Basshorns—comes in at about $170k, you’ve got to think that this is, if not a bargain, a pretty damn good deal by ultra-high-end pricing standards, especially compared to the near-million-dollar horn systems it is competing against.)

Obviously the Avantgarde/Trio-G2 system comes with my very highest recommendation—and my genuine applause for all that Holger Fromme, Avantgarde’s CEO, and Matthias Ruff have done to improve these classics. If you like your music big, powerful, detailed, beautiful, and coherent (and you have the space to house them and the money to properly amplify them), the Avantgarde Trio-G2/Basshorns are certainly must-auditions.


Type: Three-way spherical-horn-loaded loudspeaker
Power capacity: 150W
Sensitivity (1W/1 m): >109dB
Crossover frequencies: 100/600/4000Hz
Nominal impedance: 19 ohms
Recommended amplification: >2W
Recommended room size: 250ft2
CDC (Controlled Dispersion Characteristic): Yes
CPC crossover (patent pend.): Yes
Horn type: Spherical horn
Horn material: ABS injection-molded
Horn diameter: Low midrange, 37″ midrange, 22″ treble, 7″
Driver diameter: Low midrange, 8″; midrange, 2″; treble, 1″
Dimensions: 37″ x 66″ x 33″
Weight: 123 lbs.
Price: $51,000/pair

Type: Expo-spherical horn-loaded subwoofer
Frequency response: 18–350Hz
Crossover frequencies: 60–350Hz
Horn type: Expo–spherical horn
Driver diameter: 12″
Number of drivers per module: Two
Magnet material: Neodymium
Power output (RMS): 2 x 250W
REAL TIME feedback control: Yes
ADRIC circuit (patent pend.): Yes
Subsonic filter: 20/30/40Hz
Dimensions: 40″ x 29″ x 42″
Weight: 196 lbs.
Price: $39,000/pair

JV’s Reference System
Loudspeakers: Raidho D-5, Raidho D-1, Avantgarde Zero 1, Avantgarde Trio/Basshorn, MartinLogan CLX, Magnepan .7, Magnepan 1.7, Magnepan 3.7, Magnepan 20.7
Linestage preamps: Soulution 725, Constellation Virgo, Audio Research Reference 10, Siltech SAGA System C1, Zanden 3100
Phonostage preamps: Audio Research Corporation Reference Phono 10, Constellation Audio Perseus, Innovative Cohesion Engineering Raptor, Soulution 725, Zanden 120
Power amplifiers: Soulution 711, Siltech SAGA System V1/P1, Constellation Centaur, Audio Research Reference 250, Lamm ML2.2, Zanden 8120, Odyssey Audio Stratos
Analog source: Walker Audio Proscenium Black Diamond Mk V, TW Acustic Black Knight, AMG Viella 12
Tape deck: United Home Audio UHA-Q Phase 11 OPS
Phono cartridges: Clearaudio Goldfinger Statement, Ortofon MC Anna, Ortofon MC A90, Benz LP S-MR
Digital source: Berkeley Alpha DAC 2
Cable and interconnect: Crystal Cable Absolute Dream, Synergistic Research Galileo LE, Ansuz Acoustics Diamond
Power Cords: Crystal Cable Absolute Dream, Synergistic Research Galileo LE, Ansuz Acoustics Diamond
Power Conditioner: Synergistic Research Galileo LE, Technical Brain
Accessories: Synergistic ART and HFT/FEQ system, Shakti Hallographs (6), Zanden room treatment, A/V Room Services Metu panels and traps, ASC Tube Traps, Critical Mass MAXXUM equipment and amp stands, Symposium Isis and Ultra equipment platforms, Symposium Rollerblocks and Fat Padz, Walker Prologue Reference equipment and amp stands, Walker Valid Points and Resonance Control discs, Clearaudio Double Matrix SE record cleaner, Synergistic Research RED Quantum fuses, HiFi-Tuning silver/gold fuses

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