Peecker Sound AMCL2 User manual

AMCL 2
Automatic Multiband Control Limiter
Instruction Manual
Pro
f
essional Series
p
pe ee ec ck ke er r s so ou un nd d
The Sound of Entertainment

AMCL2 Professional Series
AUTOMATIC MULTIBAND CONTROL LIMITER
INTRODUCTION
INTRODUCTIONINTRODUCTION
INTRODUCTION
The Automatic Multiband Level Control AMCL2 has
been specially developed to control the sound
pressure level in an environment.
A typical example would be an amplification system
in a public premises, which must guarantee a
maximum music programme level equal to and not
exceeding the legal limits. Use of the unit AMCL2, if
correctly regulated, allows you to indeterminately
respect such restrictions even in the face of involuntary
intervention on the signal source regulation.
On the contrary to what happens to traditional
equipment, l’AMCL2 ensures a result of the maximum
quality: the sound is not affected by modulation or the
awful effects of “pumping”. Thanks to the special
circuitry adopted, the musical message is rich in
clarity in the bass notes and highly defined in the
acute ones.
FUNCTION
FUNCTIONFUNCTION
FUNCTION
The Automatic Multiband Level ControlAMCL2 has
been contrived as unitary gain equipment, fitted with
just four regulators: the input level, the release time
and the controls on the threshold intervention.
The reduced number on controls on the front panel
makes installation and tuning easier.
A locking panel prevents possible tampering by
unauthorised persons, as required by law.
AVANTAGES OF MULTIBAND LIMITERS OVER WIDE
AVANTAGES OF MULTIBAND LIMITERS OVER WIDEAVANTAGES OF MULTIBAND LIMITERS OVER WIDE
AVANTAGES OF MULTIBAND LIMITERS OVER WIDE
BAND LIMITERS
BAND LIMITERSBAND LIMITERS
BAND LIMITERS
Wide band limiters are affected by a significant
problem: the spectral gain intermodulation. In practice
the level of one part of the spectrum controls the level
of the other. A typical example is when a voice is over-
ridden by a drum roll or the sudden insert of a
speaker that lowers the rest of the music programme.
The highest energy contained tends, in fact, to control
the rest of the entire spectrum. So when the lowest
frequencies exceed the threshold limit, the highest
frequencies are toned down causing the effect of a
deep output sound.
A multiband limiter, in contrast to a wide band limiters
not subject to this type of behaviour. A multiband
limiter actually separates the audio signal into more
frequency bands and processes each band
separately. However with such a system the
parameters to control are more numerous and
complex.
The Automatic Multiband Level Control AMCL2 uses
an intelligent circuit that automatically controls all the
parameters reducing the commands to a minimum.
AUTOMATIC THRESHOLD CORRECTOR
AUTOMATIC THRESHOLD CORRECTORAUTOMATIC THRESHOLD CORRECTOR
AUTOMATIC THRESHOLD CORRECTOR
A multiband limiter divides the audio signal in more
bands, limits each band individually, and adds them
together. The result of this addition could be, however,
to have a level different from the present threshold
The conventional method provides for a wide band
limiter that elaborates the addition single bands. In
this case the disadvantages of a wide band limiter
would be introduced as previously described. In the
AMCL2 the addition of the two bands is sent to an
automatic threshold correction circuit. If the addition
exceeds the reference value the circuit individually
modifies the threshold of each band. When the
addition returns to below the reference value, the
individual thresholds of each band returns to the
original value. Such a method protects the maximum
brilliance of the sound without introducing noticeable
distortions.
Finally the AMCL2 adopts a single automatic
correction circuit for both channels: this allows for a
perfect balance of stereo image ensuring an equal
limitation of both stereo channels.
RELEASE TIME
RELEASE TIMERELEASE TIME
RELEASE TIME
The release time regulation allows for the musical
programme density modification. An extremely short
release time gives a very narrow dynamic range that
can cause distortion at low frequencies. With a
moderately short release time the output is
maintained as near as possible to the maximum. With
quite a long release time the distortion is reduced
and a softer rounder sound obtained. An extremely
slow release time determines a lower average value
output especially if the musical programme contains
notably quick variations in level (transient).
POWER SUPPLY
POWER SUPPLYPOWER SUPPLY
POWER SUPPLY
This machine has been made for use with a power
supply of 230 Vac 50/60 Hz.
The auto-reset protection fuse is situated inside.
CONTROLS AND FUNCTION
CONTROLS AND FUNCTIONCONTROLS AND FUNCTION
CONTROLS AND FUNCTION
Control of threshold levels
Control of threshold levelsControl of threshold levels
Control of threshold levels
The Automatic Multiband Level Control AMCL2 has
three controls to regulate the threshold level. The first
(5 of Fig.1),distinguished by our logo COARSE, is
achieved by a commutator (switch) with a passage of
2dB, and a range of intervention from –20dBm to
+2dBm.
The second, much more precise and distinguished by
the logo FINE (6 of Fig.1), allows for preceding
regulation correction with a field of action from –1dB
to +1dB.
If the level of the music programme to be controlled
too high and the COARSE control not enough, it is
possible to insert a third control, distinguished by the

AMCL2 Professional Series
AUTOMATIC MULTIBAND CONTROL LIMITER
logo RANGE (7 of Fig.1), which allows for an output
level reduction of 20dB.
The simultaneous use of these three controls allows
you to obtain a threshold level regulation in an
interval of 44dB.
During the operation of this device the level of audio
signal limitation is visualised on the Vumeter (2 of Fig.
1).
Automatic controls
Automatic controlsAutomatic controls
Automatic controls of Lmax and Leq
of Lmax and Leqof Lmax and Leq
of Lmax and Leq
(with chart DPC215 OPTIONAL)
The automatic control of the intervention parameters
occurs putting jumper of fig.4 in the NORMAL position.
The line signal will be like this positioned in input to
guide the device intervention.
The default values, present in production, of the para-
meters Lmax and Leq can be varied by the dipswitch
table (9 Fig.1), situated on the back panel near the
connector JUMPER CAL. The Lmax value (Fig.dipswitch
table) is changeable working on the dipswitch from 1
to 6: each dipswitch set to ON increases the Lmax
value according to the table quoted. The Leq value is
changeable working on the dipswitch from 7 to 10:
each dipswitch set to ON decreases the Leq value
according to the table.
Process Key
Process KeyProcess Key
Process Key
The AMCL2 is supplied with the button PROCESS (4 of
Fig.1) for the exclusion of the device from the
reproduction chain.
With the button in the 0FF position a direct connection
is carried out between the input and output
connectors via high quality audio relays.
INPUT AND
INPUT ANDINPUT AND
INPUT AND OUTPUT
OUTPUTOUTPUT
OUTPUT
For the input and output connection tables, refer to Fig.
2. Both principal audio input and output adopt
Cannon XLR connectors ,whilst jack stereo of 6,3 mm
are used for auxiliary connections. To guarantee the
maximum performance both input and output are
balanced without transformers.
In any case, the output stage to crossed coupling
indifferently allows for the balanced or unbalanced
connection without noticeable level differences. In the
case of unbalanced connection the unused stem (2 or
3) must be connected to the stem 1 (GROUND). The
output impedance of 70 Ohm allows you without
difficulty to guide even long capacitive lines.
On the back panel there is also a jumper to select the
function NORMAL or CAL to use when tuning the
system.
TUN
TUNTUN
TUNING THE SYSTEM
ING THE SYSTEMING THE SYSTEM
ING THE SYSTEM
After connecting the AMCL2 to the power supply and
to the input and output device, set the controls as
follows:
1. Position the button PROCESS to ON.
2. Position the button RANGE to 0dB.
3. Position the commutator (switch) COARSE to
maximum (+2dBm).
4. Position the release time to an opportune value to
obtain the functionality (see parag. Release time).
5. Keeping the jumper CAL disconnected, play
apiece of low density music (which produces the
lowest Leq level).
6. Adjust the THRESHOLD value to obtain the Leq
value desired. Work on the input attenuator until
you obtain an attenuation from about 3 to 6dB
on the display.
7. Set the Lmax and Leq values on the Dipswitch, if
different from those present in the manufacturing
(Lmax=104,5dB, Leq=95dB).
8. Insert the jumper CAL in the normal position.
9. Play a piece of high density music (that produces
the highest Leq value).
10. Carry out a period of monitoring with different
types of music and with relative data printouts, for
at least 30 mins. If the minimum values wander
excessively or defect from the values given, work
on the THRESHOLD, Lmax, Leq controls to get as
near as possible to the limits.
The points 5. 7. 8. are considered only if the optional card
DPC215 is installed.

AMCL2 Professional Series
AUTOMATIC MULTIBAND CONTROL LIMITER
TE
TETE
TECHNICAL SPECIFICATIONS
CHNICAL SPECIFICATIONSCHNICAL SPECIFICATIONS
CHNICAL SPECIFICATIONS
Input
InputInput
Input
Type Balanced electronic / unbalanced
Impedance 20 kOhm bal / 10 kOhm unbal
Max level +24dBm
Connectors XLR (Female) and 6,3mm JACKS
Output
OutputOutput
Output
Type Balanced electronic / unbalanced
Impedance 140 Ohm bal / 70 Ohm unbal
Connectors XLR (Male) and 6.3mmJACKS.
Frequency response 16Hz+100kHz +0/-3dB
TDH + Noise 0,005%
IMD (SMPTE) 0,006%
Noise/signal ratio: Reference 0dBm
-90dB with RANGE 0dB (20+20kHz)
-106dB with RANGE –20dB (20+20kHz)
Separation between channels (CROSSTALK)
86dB a 10kHz
Rejection report in common mode (CMRR) >66dB
Nominal gain 0dB
Checking Controls
Checking ControlsChecking Controls
Checking Controls
Release time from 150 mSec. to 7 Sec.
THRESHOLD level from –41dBm to +3dBm
Lmax automatic checks from 90 dBA to 121.5 dBA
Leq automatic checks from 82.5dBA to 119.5dBA
Particulars
ParticularsParticulars
Particulars
Power supply 230V~ 50÷60Hz
Consumption 25VA
Dimensions (LxHxW) 483x88x282mm.
Weight 3Kg.
Dipswitch

AMCL2 Professional Series
AUTOMATIC MULTIBAND CONTROL LIMITER
Figure 1
1) POWER SWITCH 7) RANGE SELECTOR
2) VU METER 8) JUMPER CAL
3) RELEASE TIME 9) DIPSWITCH
4) BY-PASS 10) GROUND LIFT
5) THRESHOLD LIVEL 11) INPUT GAIN
6) FINE THRESHOLD LEVEL

AMCL 2 Professional Series
AUTOMATIC MULTIBAND CONTROL LIMITER
Figure 2: Plan connection of the device and the 3-pin XLR plug

AMCL 2 Professional Series
AUTOMATIC MULTIBAND CONTROL LIMITER
Figure 3: Optional card DPC215
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pe ee ec ck ke er r s so ou un nd d
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Tel. ++39-(0)522-557735 - Fax. ++39-(0)522-393733
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www.peeckersound.com