Page 18
SP Controls, Inc.
when someone is talking excessively loud into a microphone. Or, the HF-100 can be instructed
to increase the volume when people are speaking so ly.
The DRC se ngs change the behavior of the DRC processing block.
General Char ng Overview
The x-axis of the graph shows the input sound (volume) level in decibels. The y-axis shows
the output sound level in decibels. In the example above, when the processing block hears an
average sampliing of audio at a -50 dB sound level or less, the system will increase the output
volume by a
fi
xed 8.875 dB. Beyond -50 dB the gain level will decrease to a point that at -20 dB
the incoming audio will actually be a enuated by as much as -6 dB. Finally, if a much louder
sound above -20 dB is observed the DRC block will a enuate all frequencies an addi onal
amount to limit possible clipping. The a ack me tells how quick this will happen and the decay
value explains how long the sound level will remain a enuated before resampling the audio and
returning to a new audio level.
Colors. The black line is an indicator of unity gain. That is, if the system were set such that
whatever comes into the DRC block is simply passed on to the output block. Based upon the
DRC se ngs, the blue line displays the audio level as it would leave the DRC block. Red regions
are “satua on” areas. Keep the blue line out of these areas. Ver cal magenta lines represent
the threshold marks.
Threshold 1 and Threshold 2
A threshold is a key in
fl
ec on point. It’s a key audio level in which some change needs to
happen to the incoming sound. In the example graphic above, when the incoming sound is
}
}
O
ff
set 1
(Calculated)
O
ff
set 2
Threshold 2
Threshold 1
Identity Line
(Input = Output)
New Output
After
DRC Block
Red Saturation
“Stay Out”
Zones
