Output Signal Processing Stages; Digital Delay; Filters; Compressor And Limiter - Lectrosonics DM84 Reference Manual

Output Signal Processing Stages

Each output channel provides a delay, nine filters, plus
a compressor and limiter to idealize the channel for its
function in the sound system. (See Typical Output
Signal Processing Block .)

Digital Delay

Delay on the output signal is normally used for time
alignment when loudspeakers are positioned in different
locations with overlapping coverage patterns that cause
comb filtering. The signal can be delayed up to 5
seconds in 0.5 ms increments to eliminate comb
filtering and improve intelligibility.

Filters

Up to nine filters can be implemented at each output to
idealize the output channel equalization and implement
crossover networks for bi-amped or tri-amped loud-
speaker systems.
The filter types include:
Low pass
High pass
Band pass
Parametric EQ
Low shelving
High shelving
Filter slopes can be selected with 6 or 12 dB per octave
Butterworth or Bessel parameters. Multiple filters can
be assigned to creater steeper slopes in 6 dB steps.
0.5 ms steps
Typical Output Signal Processing Block
Rio Rancho, NM
Gain Reduction Indicator
Delay Filter Stages
Off, LP, HP, BP,
0 - 5s
PEQ, LS, HS
6 or 12 dB/oct.
Butterworth or Bessel
when applicable

Compressor and Limiter

A versatile compressor and limiter are provided at each
output to control the average level and dynamics of the
audio signal, and restrict the maximum output level to
optimize the channel for its purpose. Compression is
often needed when the channel is feeding a recorder,
and limiting is often used to protect a loudspeaker
system and reduce distortion and amplifier overload.
Compressor adjustment parameters include:
Threshold
Time constant
Compression ratio
Makeup gain
Limiter adjustment parameters include:
Threshold
Time constant

Output Gain and Level Indicator

The output level can be adjusted from - 70 dBu to +20
dBu in 1 dB steps to perfectly match the requirements
of the device being fed by the channel. A bar graph is
provided by the on screen GUI to accurately indicate
the output level as it operates and is adjusted.
Activity Indicator
Activity Indicator
Compressor Limiter
Threshold Threshold
Comp. Ratio Comp. Ratio
Attack TC Attack TC
Release TC Release TC
Reference Manual
Indicator
Level Meter
Output Gain
-70 - +20 dB
1 dB steps
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