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META
SPHERICAL HORN SYSTEM
PICCO
The META PICCO is the second product in the META series
of Avantgarde Acoustic™. The horn specialists from Lau-
tertal managed to transform their eloborate spherical horn
technology into a new product with significantly reduced di-
mensions – the META PICCO is the smallest floor standing
speaker Avantgarde Acoustic™ has ever produced. It is
designed for all, to whom the shape and size of the classical
hornsystems is too spacy. Now there is a hornsystem which
combines the acoustical benefits of its bigger brothers with
an intelligibly reduzed footprint, system height and depth.
The META PICCO is a spherical 2-way hornsystem with two
active 300 mm bass drivers integrated in one single enclo-
sure. For the first time Avantgarde Acoustic™ arranges the
tweeter above the midrange horn. Here the reduced system
size is taken into consideration to allow a controlled disper-
sion on ear level heigth.
Despite its living room friendly dimensions, its sophisticated
technologies position the META PICCO in the top class.
Small but fine is the motto of the Lautertal company. Scaled
down spherical horns and special drivers with the elabora-
te OMEGA technology form the basis of this entirely new
development. The midrange runs without any filter compo-
nents in the signal path and the treble benefits from the pa-
tented CPC technology. Bass drivers and power amplifiers
correspond to the respective systems in the META PRIMO.
www.avantgarde-acoustic.de 1
2 www.avantgarde-acoustic.de
SPHERICAL HORNS
“We have a lot of friends who fancy
the dynamics and sound quality of
our horns, but who rather prefer a
smaller speaker system. So when we
started the PICCO project we first
had to design new smaller horns”
explains Holger Fromme, managing
director of Avantgarde Acoustic™.
The spherical horns SH5003 and
SH1301 is a new developement for
the compact arrangement in the en-
closure of the META PICCO.
The horn curvature is based on the
precise calculations of the physi-
cal-mathematical requirements of
spherical funnels. The typical pro-
portions of the Avantgarde Acous-
tic™ horn appearance have been
preserved. Different to the well esta-
blished 570 mm horn of the UNO,
the hornmouth of the new midran-
ge horn has been reduced to 500
mm diameter. At the same time the
designers increased the horn throat
dimensions to 75 mm.
This way Avantgarde Acoustic™ ma-
naged to use bigger drivers which
smoothly blend with the radiation
characteristic of the META PICCO.
“Our main task with the PICCO was
to achieve a perfect symbiosis bet-
ween horn and driver. In order not
to compromise the quality we had
to compensate the smaller horn di-
mensions by using a bigger and si-
gnificantly stronger driver. Although
the new horn is 45% smaller, we
managed to get the same resolution
as with our DUO system!” proudly
explains Matthias Ruff the designer.
The horns are manufactured in an
injection molding process using
high precision steel molds.
THE MIDRANGE DRIVER nology loading the new 500 mm
“Mostly people focus on treble and spherical midrange horn.
bass and completely forget about
the mids. But when we design a new “The M1 probably uses the stron-
speaker we always start with the mi- gest magnet ever being deployed
drange. The midrange is the core of in a 130 mm driver. We managed
any system. If you get this right you to further increase the effective ma-
have practically done most of the gnetic flow in the air-gap of the dri-
job” explains Matthias Ruff, techni- ver by eliminating the usual copper
cal designer of Avantgarde Acous- inlay of the pole-piece. The roll-off
tic™. The META PICCO offers the at higher frequencies caused by the
same technology as Avantgarde´s higher inductivity of the voice coil
flagship model TRIO. It features a and a specially designed cellulose
sophisticated M1 omega driver with dome was set to the exact crossover
SH1301 TWEETER HORN the OMEGA high impedance tech- point of the tweeter.”
www.avantgarde-acoustic.de 3
4 www.avantgarde-acoustic.de
THE OMEGA TECHNOLOGY
ver. No further low pass filters are necessary! CONVENTIONAL VOICE COIL VOICE COIL GAP
MIDRANGE 12 dB LOWPASS FILTER The CDC system thus causes the midrange
POLE PIECE
to only operate within their operational band
L1
and steeply fall off at the transition points.
4 OHM
C1
The attached graphics show the difference
TWEETER 12 dB HIGHPASS FILTER + LEVEL REDUCTION of conventional and the new OMEGA voice MAGNET VOICE COIL FORMER MAGNET
R1 coils. To achieve very high resistance the
C1
voice coils of the OMEGA drivers are made
4 OHM
R2
L1
with very long but very thin wires. Up to four
windings are placed on the voice coil former. POLE PIECE
Elaborate production technology is required OMEGA HIGH IMPEDANCE VOICE COIL
as the wire is so thin and easily breaks and with up to 4 layers very thin wire and minimized voice coil gap
TYPICAL 12dB CROSSOVER the voice coil gap is so narrow. Now, why is OMEGA VOICE COIL
To significantly improve the sound quality the horn manufacturer taking so much ener- tance of the crossover coil of 0,6 ohm,
Avantgarde Acoustic™´s OMEGA ap- gy and effort to simplify the passive crosso- the effective real damping factor will de-
proach is based on two major concepts: vers and enhancing the impedance of their crease to a value of only 4! Connecting
simplification of the passive crossover de- voice coils?. the same amplifier/cable configuration to
sign and high impedance voice coils. the META PICCO will result in a real dam-
The key point is the damping factor. Dam- ping factor of 18, which gives 4,5 times
Different to conventional passive crosso- ping factor is the technical term for the abi- more control and presicion! E.g. the con-
vers with six components (see graphic) lity of an amplifier to control the movement trol of the amp will increase by 450% and
the META PICCO crossover has only two of the membrane. E.g. simply speaking the at the same time will reduce the negative
components for the tweeter and no com- force the amplifier applies to the voice coil to effects of long speaker cables by 80%. As
ponent for the midrange. Using no crosso- follow exactly the musical signal. According a result the OMEGA drivers have more
ver in the midrange is usually not easy due to common knowledge the damping factor authority, less distortions and an excellent
to the large overlapping of the frequency is determined by the quotient of load impe- detailled response characteristics.
response. Using their “Controlled Dis- dance (driver) and output impedance of the
persion Characteristic” of the driver/horn amplifier. The high impedance of the voice coil
configuration, Avantgarde Acoustic™ ef- in OMEGA drivers can be best compa-
fectively controls the output. This is how An amplifier with an output impedance of red with the car tires. Big tires cause a
CDC works: The lower cut-off frequency 0,04 ohm will thus theoretically have a dam- higher rolling resistance but at the same
of a horn loudspeaker is determined by ping factor of 100 when connected to an 4 time have a much better traction. Using
the size of the horn. The larger the horn, ohm speaker. But this is a purely theoretical low impedance drivers is thus like using
the lower the response. Below the cut-off figure! In real life the signal has to pass a thin tires. Adding resistance with cables
frequency of the horn, the response falls speaker cable and the passive crossover and coils in the passive crossover, is in
off steeply at 18 dB/octave. Avantgarde components till it reaches the voice coil. this case like using thin tires with pulled
speakers thus operate only down to their Using a typical 5m long speaker cable with handbrake!.
cut-off frequency limit and require no high an W-resistance of 0,36 ohm and a resis-
pass filters. The upper frequency response
is determined by the driver. However, it
can as well be influenced acoustically ��
����
LOAD IMPEDANCE OF DRIVER
DAMPINGFACTOR
by the horn. For this purpose, Avantgar- OUTPUT IMPEDANCE OF AMP
de places a small chamber between the
driver’s membrane and the horn throat.
The driver does not emit directly but via
a small air chamber into the horn throat
opening. This air volume operates as a OUTPUT IMPEDANCE OF AMP SPEAKERCABLE COIL L1 DRIVER VOICE COIL
kind of band-pass filter and automatical- (0,04 Ω) (0,36 Ω) (0,6 Ω) (4 or 18 Ω)
ly filters frequencies above the resonance DAMPINGFACTOR
LOAD IMPEDANCE OF DRIVER
volume of the chamber (at 6 dB/oct.). By OUTPUT IMPEDANCE OF AMP + IMPEDANCE OF CABLE + IMPEDANCE OF COIL L1
choosing an adequate driver with a natu-
ral roll-off at 6 dB in this frequency range,
NORMAL SPEAKER
4
(0,04 + 0,36 + 0,6) 4
the manufactuerer obtains an acoustic at-
tenuation of the frequency response of 12
OMEGA SPEAKER
18
(0,04 + 0,36 + 0,6) 18 4,5 times better control !
dB without any passive frequency crosso- DAMPING FACTOR COMPARISON
Furthermore Avantgarde Acoustic™ First it reduces partial resonances of
added a powerful ALNICO magnet the cone. “It is similar to a waterbed
to this new M1 omega develop- with only one chamber. Once you
ment. This precious magnet mate- move it takes years till the movement
rial generates a powerful magnetic of the water comes to a halt. Using
field which homogeneously controls multiple chambers in waterbeds will
the movement of the voice coil. immediately calm any motion” exp-
lains Matthias. “Same with our VDE
The midrange cone of the META drivers. Any movement of the cone
PRIMO is coated with trillions of tiny itself is dampened by these micros-
microfibres generating a “VELOURS copic fibres”.
DAMPING EFFECT”. According to
the manufacturer, this incremental- The second benefit of the VDE tech-
ly small fur of the VDE technology nology is that it effectively absorbs
cone effectively works in two ways. high frequency distortions. M1 ALNICO MAGNET
www.avantgarde-acoustic.de 5
“If your listening room sounds hard
you will probably use a carpet or
hang up a curtain. That´s how simp-
le VDE works. The irregular surface
of the cone just eats up unwanted
harmonic distortions.”
The generously dimensioned ALNI-
CO magnetic structure of the 130
mm (5 in) cone, provides an exten-
ded efficiency as well as offering
very high power handling at long
excursions. This way the M1 ome-
ga has a very low cut-off frequency
of 290 hz which allows for an inte-
gration with the subwoofer without CPC CROSSOVER BOARD
any passive crossovers. The design
of the dome ensures the sound THE TWEETER “The spherical horns are so re-
waves entering the midrange horn In the treble of the META PICCO vealing that we had to restrict the
SH5003 are in phase and cover the Avantgarde Acoustic™ uses a high number of parts to the absolute mi-
required extended bandwidth. impedance version of the H2 dri- nimum and use only highest grade
ver of the DUO. This exceptional components”.
The CDC system features a cont- driver combines the smoothness of
rolled roll-off at 3,000 Hz and con- an electrostatic driver and the po- A potential limitation of any passive
sequently allows the operation of wer of a strong 1 inch horn driver. crossover is the capacitor required
the M1 omega in full range mode, The H2omega features a voice coil to filter low frequencies. A capacitor
without any degrading filter compo- former made of Kapton with a mini- consists of two plates or conductors.
nents in the signal path. mised air gap, a special geometrical As both plates are separated by a
shape of the 17 ohm voice coil and dielectric or insulator, the conduc-
“When you connect your Avant- an ultra light diaphragm. The mere tors have no direct contact but the
garde speaker the voice coil of the force of the 3 kg (6.5 lb) magnet signal is passed through a dielectric
midrange driver is directly linked to on the voice coil guarantees 100% field. Every time the music signal is
your amp. No phase shifting com- detail and precision even at low vo- changing from the positive to the
ponents in between, only the spea- lume levels, and provides the META negative half-wave and vice versa
ker cable! You can´t get an any bet- PICCO compression-free sound the dielectric field gets inverted.
ter direct connection.” reproduction at extreme sound
pressure levels. With the spherical This permanent change of direction
The M1 omega offers a neutral, silky horn SH1301 the H2 omega offers of the field in a capacitor - a phe-
and contoured sound reproduction an ultra wide bandwidth down to nomen called “dielectric memory
across its entire frequency range. 900 Hz. Due to the passive cros- effect”- causes distortions which get
Vocals, instruments and complex sover point being only at 3,000 Hz worse the closer the signal passes
signals are reproduced with speed Avantgarde Acoustic™ achieves a through the zero point and are at
and ease that will let you forget that seamingless smooth sound with in- a max just when the electric field
you are listening to a recording. credible dynamic headroom. changes its direction.
THE CPC CROSSOVER
Although the M1 omega midrange
driver is running full range without
any crossover, the H2 omega re-
quires a passive filter for thermal
protection. “I would have loved to
completely eliminate the crossover
for the tweeter, but its physically
not possible. The voice coil of the
tweeter would simply melt having to
cope with unfiltered bass signals”
resumes the designer.
So the manufacturer was forced to
research on components for passive
crossovers. As with all their products
Avantgarde Acoustic™ was taking a Filter output vs distortions photos of capacitors
very puristic approach. Less is more in a high pass filter at various frequencies
H2 OMEGA TWEETER is the design philosophy. CAPACITOR DISTORTIONS
6 www.avantgarde-acoustic.de
THE CPC TECHNOLOGY
The permanent change of direction of the NORMAL CAPACITOR
field in a capacitor - a phenomen called
“dielectric memory effect”- causes distor- MUSIC
tions which get worse the closer the signal
passes through the zero point and are at
a max just when the electric field changes Every time the music signal is
its direction. The attached pictures show changing from the positive to
these distortions of capacitors at different the negative half-wave and
frequencies. vice versa the dielectric field
gets inverted
To avoid these distortions Avantgarde CPC CAPACITOR
Acoustic™ uses with the “Capacitor Pola-
risation Circuit” an elaborate approach.
MUSIC
Different to conventional capacitors the
CPC–capacitor has multiple conduc-
tor–foils connected with a special electric
layout shown in the attached graphics. The
CPC module up-converts the income mu-
sic signal to the required voltage to bias
the conductors. Only the inner conductor
is biased with DC. In the CPC module a 100 VOLT
voltage cascade through a network of di-
odes increases the voltage of the music
signal to a multiple. This high direct cur-
CPC MODULE
OUTPUT
rent is than fed into the inner conductor.
Furthermore is the diode circuit electrically
INPUT
decoupled through a very high impedance
transformer to avoid any backlash to the
music signal. Already a view moments after
turning on the music the CPC module has
generated the required direct current to
bias the capacitor. As the CPC diode cas-
cade can build-up voltages by far beyond
allowable levels, Avantgarde Acoustic™
has included a protective circuit to avoid
overloading the capacitor. OUTPUT
Non-linearity of the oszcillating
100 VOLT LIMITER 100 VOLT
POLARISATION VOLTAGE
electrical field caused by the
dielectric memory effect
Linear modulation of the
always positive electrical field
due to the 100 V CPC bias
of the dielectric separator
INPUT
UP CONVERTION STEPS
MUSIC SIGNAL
BIASED ELECTRICAL FIELD CPC UPCONVERTION OF MUSIC SIGNAL
A solution according to Avantgarde the lesser the wind can distort the is biased with a direct current so it
Acoustic™ is to apply a strong force picture. You only have to make sure has a strong electric field strength in
which holds the electric field in one that the cloth is not torn apart”. one direction. This force is far abo-
specified direction no matter what ve the zero crossing point and much
the music signal is doing. Matthias The solution was to find a way to higher than the actual peak signal
Ruff tells about when he first got prevent the electric field through the of the music. The electric field now
the idea of the so called “Capaci- insulator to reverse its direction. By remains in its orientation and can-
tor Polarisation Circuit” to solve the developing a new type of capacitor not be modulated any more by the
problem: with an active polarisation circuit signal.
Avantgarde Acoustic™ claims to
“2004 in Athens I observed an have solved the problem. “We de- To get this theoretical principle to
Olympic flag. As it was only fixed veloped an unconventional type of work, Avantgarde Acoustic™ had
on one side it was flattering in the capacitor with multiple conductors to overcome two problem areas. At
wind. I could see the Olympic rings connected with a special electric first the designers had to make sure
but they were distorted by the wave layout. These where than used to that the induced direct current does
motion of the flag. If the cloth would induct a high voltage to polarize the not reach the speaker. DC would
have been stretched on both ends capacitor” explains the designer. heat up and likely destroy the voice
the rings would have been better vi- The function of the concept is fair- coil. “Our capacitor is constructed
sible. The more the flag is stretched ly simple. The field in the dielectric in a special way. Instead of only two
www.avantgarde-acoustic.de 7
plates we use multiple conductor
foils. Only the inner conductor is bi-
ased with DC. This way no current
can leak”.
Having executed numerous test
and listening sessions Avantgarde
Acoustic™ verified that whenever
the polarisation current was dupli-
cated the distortions decreased and
an audible improvement could be
heard. This means that ideally the
polarisation current should be as
high as possible and is only limited
by the load capacity of the capa-
citor.
Now the task of the designers was
to find a simple way of providing
the required direct current. Using
an external power supply would not
have been practical and batteries
were excluded as they did not pro-
vide a high enough voltage. Instead
Avantgarde Acoustic™ uses its pas-
sive CPC board (Capacitor Pola-
risation Circuit; patent pend.). As
the music signal is providing the re-
quired electrical energy to drive the
CPC module no additional power
supply is needed. The CPC module
now automatically up-converts the
income signal to the required volta-
ge to bias the conductors.
A CPC biased capacitor has less
distortions and can more precisely
handle incremental signal variati-
ons. “The effect of CPC is amazing.
When executing our AB compari-
sons, we could immediately hear
the difference. There is much more
detail and I thought the treble level
has been increased. But at the same
time the sound got much sweeter.
Subtle nuances are totally detached
to project lifelike aura of spaces and
instruments” raves Armin Krauss,
customer support manager of
Avantgarde Acoustic™.
THE ACTIVE SUBWOOFER
In the bass of the META PICCO
Avantgarde Acoustic™ melts the
prooven technology of the SUB225
subwoofer with the drivers and po-
wer amplifiers of the META PRIMO.
As the META PICCO subwoofer
does not have a horn flare, the AD-
RIC compensation circuit has being
replaced by an active REAL-TIME
controller. This REAL-TIME control-
ler compensates deviations of sig-
12X600 BASS DRIVER
8 www.avantgarde-acoustic.de
nal and driver movement and line-
arizes the low frequencies down to
18 Hz. Although the volume of the
META PICCO enclosure is relatively
small for two 12 inch drivers of this
caliber, the Avantgarde Acoustic™
REAL-TIME controller ensures preci-
sion and low frequency extension.
“Our active REAL-TIME controlled
systems are superior to any pas-
sive subwoofer on the market. Be-
sides the linearity of its frequency
response and the lower frequency
extension, the major benefit is the
compensation of all mass related
deviations from the input signal
throughout all volume levels.” ex-
plains Matthias Ruff. According to
the designer the inertia of the heavy
bass membranes is the cause for
problems all passive speakers are
facing. When not beeing in motion
inertia is the force which opposes
the acceleration of the membrane.
“Typically passive speakers have no
bass when driven at low volumes!
Only when turning up the volume
the heavy membranes start moving
and only than bass becomes au-
dible”. Different to this, when be-
eing in motion inertia is the force
which opposes the deceleration of
the membrane. “Passive speakers
have a certain volume level they are
confinient with. First they have no
bass and when you play louder they
become ok. But if you than further
increase the volume level they will
start sounding boomy. That´s phy-
sics and there is nothing you can do
against in a passive system.”
For these reasons Avantgarde
Acoustic uses its REAL-TIME cont-
roller to compensate the inertia of
its bass membranes. The controller
always compares the accelaration
of the driver with the input signal. At
low volumes the circuit detects that
the driver is not start moving as it
should and increases the inphase
signal strength. At high volumes it
detects that the membrane wants to
continue moving although it should
stop. The electronic increases the
opposing electronic forces.
“Our REAL-TIME controller signifi-
cantly increases the dynamic win-
dow of our speakers. From very
low volumes to very high volumes
the speaker will not loose its tonal
AMPLIFIER BOARD REAR VIEW
www.avantgarde-acoustic.de 9
AMPLIFIER BOARD
balance. Turn the PICCO to back- three zones and fine adjusted with CO. The slightly recessed profile of
ground volume, listen and you un- a attentuator. The low frequency re- the cabinet in exclusive wood finish
derstand what I mean” raves Holger sponse can be set with a 3-position with its tender rear section gives re-
Fromme. subsonic switch. The system can be miniscence to the bigger META PRI-
remotely switched on/off using the MO but at the same time continues
The bass of the META PICCO is dri- 12V trigger signal of AV amps. the heritage of the characteristic
ven by two 30 cm (12 inch) long- tripod concept of the existing PRO-
excursion 12X600 drivers with each Each of the two powerful twin amps LINE series. The driver front panel is
600 watt RMS power capacity. The have 2 x 250 watts and are powered visually detached from the wooden
paper membrane combines stiffness by a mechanical decoupled 540 VA cabinet by a subtle 6 mm shadow
and acoustical neutrality with low toroidal transformer buffered with gap. “With this small gap the horns
mass. The 4 inch voice coil of the 80.000 uF capacitance. The ela- seem to float in a frame build by the
12X600 provides a powerful drive borate mechanical mounting with cabinet. It puts the spherical horns
with high thermal handling capabi- four buffers completely decouples elegantly in scene.”
lities. The 230 mm magnet with a the power transformer from the
weight of 9 kg generates a BL factor heat sink and thus inhibits induced “As a horn is something of everlas-
of 20 N/A. vibrations. The total of 1.000 watt ting value, we purposely refused to
of integrated amplifier power in the follow fashion and trends.” finalizes
Each speaker is equipped with its META PICCO provides sufficient re- Hannes Wettstein his philospohy.
own REAL TIME power module. serves and headroom.
The active modules are connected “In the design of the PICCO the
through line or speaker level con- THE PRODUCT DESIGN lust of sounds and luxury explores a
nections. The input level attenua- As with the META PRIMO zed., visual and content-related minima-
tor adjusts the volume between the the renowned Swiss designstudio lism. A lean style combined with a
bass and the spherical midrange around designer Tobias Adami and nearly exaggerated composition of
and tweeter horns. The crossover Hannes Wettstein account for the small detail visualizes the quality of
frequency range can be shifted to product design of the META PIC- the technology inside.”
12X600 BASS DRIVER MECHANICAL DECOUPLING OF THE 540 VA TRANSFORMER
10 www.avantgarde-acoustic.de
SPECIFICATIONS
SYSTEM DATA
Frequency response – Bass 18 — 350 Hz
Power handling 70 Watt
Sensitivity (1W/1m) > 106 dB
Crossover frequencies 300 / 3.000 Hz
Nominal impedance 18 Ohm
Recommended amplification > 15 Watt
Recommended room size > 16 qm
CDC yes
HORN spherical Horn 180°
Diameter Midrange 500 mm
Tweeter 130 mm
Horn-length Midrange 280 mm
Tweeter 60 mm
Horn-area Midrange 0,196 qm
Tweeter 0,013 qm
Diameter driver Midrange 130 mm
Tweeter 1 Zoll
BASS DRIVER 2 drivers per channel
Power handling - RMS 600 Watt
Nominal diameter 300 mm
Voice coil diameter 100 mm
Magnet diameter 228 mm
Magnet weight 10 kg
VERSTÄRKERMODUL 1 modules per channel
Amplifier power output - RMS 2 x 250 Watt
Power supply 80.000 µF
High quality toroidal transformer 540 VA
Active crossover variable, 60 — 350 Hz
Subsonic filter, 3-position 20 — 30 — 40 Hz
Audio transformer yes
SoftStart circuit yes
REAL TIME control yes
ADRIC-compensation —
Low and high level inputs selectable
12V remote ON/OFF integrated
DIMENSIONS / WEIGHT
Dimensions (per speaker) Width 500 mm
Depth 560 mm
Height 1.255 mm
Weight (per speaker) 85 kg
www.avantgarde-acoustic.de 11
ACCADEMIA
dell´ AUDIO
HIGH END
DESIGN AWARD
Avantgarde Acoustic™ GmbH
Nibelungenstr. 349
D–64686 Lautertal / Germany
Tel: +49 (0) 6254/306-100
Fax: +49 (0) 6254/306-109
email: info@avantgarde-acoustic.de
