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DPA Series — DPA80/DPA100 Operating Instructions
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Operating Your Amplifier: Understanding the Metering
The metering on your DPA Series is both comprehensive and simple, but it is worth knowing
what points in the signal path are being monitored and how the readouts are affected by
changes during editing.
LED Meters
When the BANK selected is Input A-D, the LED meters are showing input level pre-
processing, monitoring the output of the ADC or digital inputs. If the RED LED illuminates, it
is indicating that the clipping point of the converter channel has been reached (with 1dB of
headroom).
Adjusting input gain or EQ will NOT affect the level shown on these meters.
If a digital source is selected (either network or AES)
then the level shown is relative to 0dBfs. If the RED
LED illuminates, there is less than 1dB of digital
input headroom left.
Obviously it is desirable, in the case of analogue
inputs, to operate with a good level of input signal, to
maximize converter resolution and to minimize
noise. Operating with approximately 6 - 12dB of
headroom is a good reference point (so peak signals
illuminate the yellow LED).
With digital input sources, it is not uncommon for the RED LED showing input clip, to
illuminate on peak signals — especially when using AES digital sources that are pre-mastered
(such as prerecorded audio files and CDs). This is NOT a fault — the signal has already been
optimized as for analogue input sources. DO NOT attempt to increase digital input gain
before the amplifier in these circumstances as there will be severe digital clipping which
sounds a whole lot worse than clipping the analogue input stages and can kill HF and mid
drivers even at relatively modest output levels!
When the BANK selected is either Out 1-4 or Aux 1-
4, the LED meters are showing output level,
relative to the channels’ limiter threshold.
Adjusting the limiter threshold will therefor affect
the scaling of these meters, designed to show how
close a channel is to limiting, and if it is being
driven past the limiter threshold and is into
limiting.
The yellow LED illuminates at the point of limiting,
and the red LED indicates that there is 4dB or more
of gain reduction happening (so 4dB or more over
the threshold). Metering is also affected by the settings of the limiter time constants, so
expect meters on LF and sub outputs to appear “slower” in response time to those on HF
channels.
Any output gain or EQ changes will affect the levels shown on these meters.
