Pilot tone generator
The DPA output stage contains an internal, configurable pilot tone generator which can be
switched to the output channels. The pilot tone generator is configured using the IRIS-Net
software. The following table sets out the available parameters.
Notice!
Under certain conditions (such as high level or speakers with high sensitivity in the high
range), it may still be possible for some people to hear the pilot tone. If this is the case,
increase the frequency.
Notice!
The switching of speaker lines with an active pilot tone can be heard under certain
circumstances. It is therefore not advisable to use the pilot tone in “1 in N”-type line
topologies.
Parameter
Default setting
Range/values
Generator
Off
On or off
Frequency
19,600 Hz
15,000 Hz to 25,000 Hz
Amplitude (depending on
load)
6 V
6 V or 12 V (Note: The 12 V setting is only
available for devices with a serial number
above 20,000.)
Table 7.3: Parameters of the pilot tone generator
Impedance measurement
The DPA output stage is equipped with a speaker line impedance measurement function. This
function measures the effective values of the output current and the output voltage, and the
impedance value of the connected speaker line is calculated using these measurements. Due
to the frequency and temperature dependence of the speaker line, the value obtained can vary
substantially. A continuous sinusoidal signal with an appropriate frequency is recommended
for the measurement. The voltage and current measurements do not claim to be a calibrated
measurement of absolute values. The measured value is compared with the reference
measurement for the amplifier/measuring system in question and a good/bad status is
indicated depending on the difference between these two values. If the amplifier is replaced,
the reference measurement must be performed again.
The impedance measurement is configured using the IRIS-Net software.
R
i
R
o
Amplifier
Speaker
Figure 7.6: Input resistance R
i
and output resistance R
o
of the DPA output
7.4
7.5
30
en | Safety information
PROMATRIX 8000 POWER AMPLIFIER
19-Aug-13 | 03 | F01U217494
User manual
Summary of Contents for DPA 8150
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