IMG STAGELINE 25.9510, Instruction Manual

Page: 23 / 48

23
English
Values for the limiter :
Threshold: threshold value in dBV (0 dB = 1 V); the gain will be at-
tenuated when the signal level has exceeded this value
(= max . output level allowed)
The value set here will be the upper limit for the threshold
value of the compressor .
Release: release time, i . e . the time the gain takes to reach its
original value after the signal level has fallen below the
threshold value
7.4.5.1 Setting the limiter
To limit the load of the speaker to a specific value, approximate the
setting of the limiter threshold by means of the following formula:
Value of the limiter threshold: = 20 log
10
√ P
lim
/ P
nom
P
nom
: rated power (RMS power) for the corresponding imped-
ance
P
lim
: desired maximum power for the same impedance
Example:
At the output CH A OUT of the STA-1600DSP, an 8 Ω speaker is to be
limited to a power of 50 W:
P
nom
= 500 W at 8 Ω (cf . chapter 10)
P
lim
= 50 W
Value of the limiter threshold = 20 log
10
√ 50 W/ 500 W = −10 dB
8 Application Example: Crossover Network
Fig . 18 shows how a crossover network for a two-way speaker system
can be implemented by means of an amplifier .
– The output of the audio source is connected to the input CH A IN .
– By means of an XLR cable, the signal is routed from the jack LINK
OUT of the input CH A IN to the input CH B IN .
– The operating mode STEREO is selected .
– The high-pass filter is active in channel A; the low-pass filter is active
in channel B . Both filters are set to a crossover frequency that is
matched to the speakers used .
– The tweeter is connected to the output CH A OUT; the bass speaker
is connected to the output CH B OUT .
– The volume balance between the high-frequency range and the
low-frequency range can be changed by means of the setting GAIN .
– Depending on the position of the speakers, signals can be delayed by
means of the signal delay DELAY to compensate different distances
between the speakers and the audience .
– The filters of the parametric equalizers can be used to compensate
room resonances, for example .
– To protect the speakers against overload, the level limiter LIMITER
can be used .
9 Protective Circuit
The protective circuit is designed to prevent damage to the speakers
and the amplifier . The LED indicator PROTECT (1) will light up while
the protective circuit is activated:
– for a few seconds after switch-on (switch-on delay)
– when the amplifier is overheated or when there is a short circuit
at a speaker output
– when the unit is being switched off
When the LED indicator PROTECT lights up during operation, when it
does not extinguish after switch-on or when the circuit breaker (14)
has tripped, switch off the amplifier and eliminate the error . If required,
press the button of the circuit breaker to reset it .
10 Specifications
Model STA-1600DSP STA-2200DSP
Output power
RMS power
Stereo at 4 Ω
Stereo at 8 Ω
Bridge at 8 Ω
Peak power
2 × 800 W
2 × 500 W
1600 W
2700 W
2 × 1200 W
2 × 750 W
2200 W
3000 W
Amplifier class AB H
Input sensitivity 1 V
Input impedance 20 k Ω (bal.)
10 k Ω (unbal.)
Frequency range 20 – 20 000 Hz (±1 dB)
S / N ratio > 90 dB
Channel separation > 55 dB
THD < 0.1 %
Power supply 230 V/ 50 Hz
Max. power consumption 2600 VA 3400 VA
Ambient temperature 0 – 40 °C
Dimensions (W × H × D) 483 × 88 × 430 mm 483 × 88 × 496 mm
Rack spaces (RS) 2
Weight 17 kg 23 kg
Subject to technical modification .
Fig. 18 Example: crossover network
MUTE
HPF PEQ 1 – 9
out
in
LIMITER DELAY
out
in
COMPRESSOR GAIN PHASE
INVERT
D
A
LINK OUT
CH A IN
CH B IN
CH A OUT
CH B OUT
HF
LF
A
D
Signal
Source
MUTE
LPF PEQ 1 – 9
out
in
LIMITER DELAY
out
in
COMPRESSOR GAIN PHASE
INVERT
D
A
Work
Mode
STEREO
A
D
X-Over
PEQ
Work Mode Delay Gain
Phase
Compressor
Limiter
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®
INTERNATIONAL GmbH & Co. KG.
No part of this instruction manual may be reproduced in any form or by any means for any commercial use.