|This Avantgarde duet delivers audio bliss
by Ernie Fisher
For this evaluation, I broke my self-imposed rule and auditioned
the system at one of my loyal reader’s house. Chris,
the man of the house, has been an audio enthusiast as long
as I can remember — since about the early seventies.
In those days, I was still retailing and had sold him the
odd component. Chris has a great collection of audio gear,
which includes amplifiers from Art Audio, McIntosh, Bryston,
Audio Aero monoblocks, Luxman, classic Fisher tube receivers,
etc. He also owns the Audio Aero Prestige CD player, WLM
speakers, Brinkman turntable and a whole slew of cables and
other gadgetry. To call him an audiophile is an understatement
as he is more of a critic who often auditions audio components
for fun, as a hobby. Chris and his wife Denise are blind,
consequently relying on their ears to deal with life’s
obstacles. I suppose that, due to their handicap, this couple
has developed, not only a keen sense of hearing, but also
a profound sense of awareness. When it comes to audio, they
are not distracted by appearance and the only yardstick to
judge a system’s performance is (as it should be) music.
I am quite sure that Denise and Chris hear stuff that is
likely inaudible to others.
Chris recently bought the Avantgarde speakers and investigated
the addition of a suitable amplifier, one that is a synergistic
match. This inspired Globe Audio’s Jody Hickson and
the integrated amplifier arrived for an audition. It arrived
at about the same time as I did and the listening sessions
began a short while later.
Before we get to the important stuff, it should be noted
that Avantgarde has been around for a number of years and
I have often listened to their horn speakers at trade shows.
To tell the truth, I have heard them sound great as well
as poorly and I was curious about the sonic makeup of these
impressive-looking horns. For my auditioning session, I agreed
to bring my own music — a collection of classical,
jazz and blues, of course. As the amp drives the top frequencies
of the Horns let’s get to it first.
Model Three integrated amplifier Appearance
The unit has clean lines and features an uncluttered faceplate
that accommodates only the input selector and the volume
control. The electronics are housed on a rigid chassis
in a compact enclosure with ventilation slots on the top.
The faceplate is finished in matted aluminum while the
cover is completed in powder-coated gray.
On the unit’s rear, two pairs of balanced XLR sockets
and three pairs of single-ended RCAs make up the inputs.
High quality WBT terminals allow solid connection and the
balanced preamplifier output features male XLR sockets. There
are five I
nputs for source components and one can be configured as
an AV-direct input making it possible for use in home theatre
systems as a power amp for the front channels.
A pair of unbalanced RCA outputs (REC OUT) taps the input
signal and allows for analog recordings (on tape, open reels,
DAT, hard disc etc.).
The main power switch is also located on the unit’s
rear. The source selector on the front panel serves as a
standby switch (red display illumination). If MUTE is selected,
(only available by remote control) the display is partly
All in all, Avantgarde managed to maintain an elegant look
in a simple, timeless design that contains contemporary technology.
Model Three integrated Amp Technology
This isn’t your everyday integrated amp with loads
of power. Rather, the Model Three has been designed to achieve
the pinnacle of performance with all sorts of very efficient
loudspeakers, including, but not limited to Avantgarde horns.
It is a solid-state design that provides 0.4 watts/ch into
an 8 ohms load, (1.1 watts/ch into 20 ohms) in pure CLASS
A mode. In the CLASS AB mode, the amplifier delivers up to
38 watts into an 8 ohm load. When employed with Avantgarde’s
highly efficient horn speakers, the unit generates more than
enough power at any given moment.
The Model Three amplifier has only two amplifying stages,
a simple and fast design that boasts remarkably short signal
paths that guarantees fast signal processing and thus, works
with higher efficiency. The amp operates at very low feedback.
A cascode power stage circuit provides considerably increased
bandwidth and resolution. Cascode-based designs produce high
gain with low noise — a type of circuit in which a
grounded emitter input stage is coupled directly to a ground-base
(or grit) second stage. A further positive side-effect of
the cascode stage is the “immunity” of the power
output stage for fed-back EMF (electro-magnetic forces) from
According to Avantgarde, this and the additional parts required
for the complex circuit ensures that the amplifier doesn’t
change the music signal by having to compensate a complex
reflux signal from the loudspeakers.
The amp’s parts are beautifully arranged on a unique
chassis. It is made from 2 mm aluminum, shaped to prevent
the development of resonance, laminated and coupled to a
solid 20 mm aluminum face plate. Further strengthening is
achieved with 10 mm aluminum “rails”, which also
accommodate the power transistors and serve as heat sinks.
The unit’s power supply boasts a proprietary toroidal,
statically and magnetically shielded transformer. It provides
seven separated secondary voltages for various circuits (e.g.
driver stage, display, relays etc.), thus minimizing internal
interference. In addition, the voltage supplies are buffered
individually, e.g. the power stage possesses 40,000 µF
of exclusive filter capacitance.
Duo Grosso Speaker Appearance
The horns almost demand your attention as they rise above
the bass enclosures and most of your furniture. As beauty
is in the eye of the beholder, I’ll leave it at that.
My personal take on the subject of beauty is that nothing
can replace a beautiful lady, and audio is rarely better
than unpretentious. However, I see and hear simultaneously,
which results, like it or not, in some form of bias — and
I admit having been seduced by looks and performance occasionally,
when I was a lot younger.
Having said this, I must admit that I like the Avantgardes
for their obvious function as well as the19th century styling.
Horns, in case you are wondering, were first used decades
ago (amplified horns were first seen about 80 years ago).
Thus, the Duo Grosso horns convey old-fashioned speaker technology,
but in a very neoteric variation, and even if one isn’t
particularly fond of their appearance, they convey importance
to an audiophile. The standard version of the Grossos comes
with several metallic lacquer finishes for the horns. The
circular housing tubes and the three-pillar steel tube frame
is powder-coated in black. The rear covers and the subwoofer
enclosures are coated in a high quality NEXTEL finish. Special
designs are optional. The enclosures are equipped with spikes
or pads. Each speaker measures 26 inches wide, 26 inches
deep, 61 inches high and weighs in at 206 pounds.
The picture tells the story of a completed speaker system,
whereas the technology is only partially apparent, It begins
with the structure of the system. Each enclosure is constructed
from 1.2 inch MDF (30mm) and has a strategically placed
stabilizer, which renders a very rigid enclosure to prevent
The midrange is mounted into orbicular housing tubes. A
three-pillar steel-tube frame is used to support the midrange
horn with chrome screws on lateral fixtures. To restrict
vibration and resonance, rubber pads have been employed between
the frame rails and the (subwoofer) enclosure. The tweeter
is placed in a specially designed, sealed enclosure in the
top section of the subwoofer. The more complicated matter,
the Duo Grosso’s assemblage, is described briefly in
the following overview.
The design is a rather complex arrangement of subwoofer,
crossover, gain control and, the company’s specialty,
the midrange horn and high frequency horn-driver.
Each enclosure contains two active subwoofers (SUB231-G)
with 12 inch long-excursion drivers. Two powerful 250 watt
amplifiers — one for each driver — allow integration
via an active (electronic) crossover. This arrangement provides
ample adjustments to attain musical and acoustic coherence.
According to Avantgarde, the design boasts a real-time feedback
loop to remove deviations of the amps and the drivers. Consequently,
the SUB231-G achieves flat frequency response down to 18Hz — considerably
lower than all program material.
The SUB231-G can be connected by way of WBT speaker terminals
for direct connection to integrated or power amplifiers or,
optionally, via XLR terminals. The system provides a signal
with high impedance and is also balanced and transformer-coupled,
thereby avoiding hum and noise and enabling connections to
balanced or bridged amps.
Avantgarde designed all drivers, but the M2-Omega midrange
unit — the horn — certainly is the focus of attention.
It’s the same one as employed in the top-of-the-line
Omega models and has a seven inch cone, backed with a large
magnetic structure. It can handle a lot of power that generates
long excursion characteristics. In this design, the horn
has been engineered to operate between 170Hz and 2,000Hz.
It is accomplished with a Kevlar diaphragm coated with a
A four-inch paper dome directs the generated sound waves
into the horn and assures phase integrity over its rated
frequency reach. Microscopic fibres cover the entire surface
of the midrange membrane, a process called Velours Damping
Effect. Avantgarde features a “controlled dispersion
characteristics” (CDS) system that rolls off at 2,000Hz
and consequently allows the operation of the M2-OMEGA without
any degrading filter components in the signal path.
The tweeter — a slightly modified rendering of the
Omega model — is said to mimic the smoothness of an
electrostatic driver and the force of a one-inch horn. It
boasts a 6.5 pound magnet on its voice coil and, along with
a very high efficiency rating, blends with the horn via a
passive crossover at 2kHz. Frequency response for the entire
system is from 20Hz to 20kHz; sensitivity is 107dB watt/metre;
crossover points are 170Hz and 2kHz; Impedance is 18 ohms;
variable active crossover is adjustable from 60Hz to 220Hz.
The System’s Sound
First, I listened to the Duo Grossos’ horns connected
to an Art Audio Carissa amplifier with the Luxman C-800 preamplifier.
The loudspeakers’ crossover to the bass drivers setting
was at about 25Hz with the built-in amp’s gain adjusted
to blend with the horn. I was happy with the harmonic-rich
sound, I liked the midrange glow and liked the warm quality
of the high frequencies, but found a slight lack of firmness
and resolution at frequency extremes — the bass and
treble areas. However, I assure you, this is faultfinding
at its best (or worst) as I could live with that system combination
and enjoy it. Had I not auditioned the system with another
amp, I’d have said “great sound” and leave
it at that. But here is where conclusions become perplexing,
as the Art Audio power amp/Luxman preamp was replaced by
Avantgarde’s Model Three integrated amp. After a couple
of hours of warm-up, I listened to my compilation of tunes
Connected to the Model Three, the horns began to show their
awesome musical authority. It became obvious that the amp
is a perfect synergistic match as it improved the already
great-sounding combination of the Art Audio amplifier/Luxman
preamplifier. The Model Three introduced the kind of midrange,
I’d call transparent; but along with the see-through
quality that allows the musical information to reach the
ears totally unobstructed by the equipment, there is no denying
the amp’s ability to resolve every note from upper
bass to midrange. The Duo Grosso speakers, when connected
to the Art Audio amp, had full, melodic mid-bass, though
a touch overripe. With the Model Three amp in the system,
mid-bass became well tempered, resolute all the way down
to the crossover point of the woofers, but it took about
one hour of play before it performed to perfection. My own
preference (bias) is sound that transcends amp and speaker
personalities and offers the most organic tonal quality.
This said, I feel that the Avantgarde system has a sonic
signature, not intrinsically organic, but delightfully musical,
the sonic signature signed by an artist who understands tonal
As big as these horns are, when they are connected to the
right amps and placed a minimum of three feet away from the
rear wall of the listening room, they fade into a harmonious
musical panorama. Though they will be conspicuous in all
listening environments, they have the ability to set up and
dissolve into an awesome sound stage that allows a grand
perspective of the musicians and their instruments.
I didn’t expect the Model Three to outperform an outstanding
amp/preamp combination, but it did in this system combination.
I have no idea what the Model Three sounds like with different
speakers, but, based on what I heard, I assume that it will
match well with many highly efficient loudspeakers.
I feel that the electronics industry is part of the entertainment
profession, where art is as important an issue as the manufacture
of electronic gear. Many entertainers are held in high
regards for their ability to enthrall us, whether they
act on stage or in film, recite poetry, song or music;
and it is much the same with audio. I believe that, in
the entertainment world, the audio industry delights us
with reproduced art — music and theatre — and
could be classified as part of the arts. In Greek mythology
there were gods, female divinities to be sure, and these
mythical ladies we supporters and defenders of art. The
were known as the nine muses and I can think of at least
three of them — Euterpe (music), Erato (lyric and
love poetry) and Terpsichore (dance and song) that could
be the masters of the audio industry’s universe.
For centuries, these mythical ladies promoted art by encouraging
inspiration, purpose and creativity, which results in art.
The Avantgarde system can be considered art — audio
art, which transcends technological wonders and offers some
of the best entertainment I’ve run across in years.