ArtsCompressor compresses the sound.
Compression is a dynamic operation that consists of two parts:
(
1) the current input volume of the signal is detected
(
2) if it exceeds a given theshold, the volume of the output signal will be reduced
The input volume detection has an attack and a release half-life time which can be specified - in milliseconds - with the corresponding properties. This envelope causes the compressor to adapt slowly to the actual input signal level.
The ratio specifies how the volume of a signal should be reduced, if it exceeds the threshold. A compression ratio of
2:
1 means for instance that if the input volume is
2 dB over the threshold, the output volume will be
1 dB over the threshold. Example (threshold =
-10, ratio
2:
1):
input =
-20 dB => output =
-20 dB
input =
-10 dB => output =
-10 dB
input =
0 dB => output =
-5 dB
input =
10 dB => output =
0 dB
input =
20 dB => output =
5 dB
Compression is often thought off as an operation to make music "sound louder". To achieve this, the first step is to reduce the dynamic range like in the example above. As the loud parts of the music have been reduced in volume, we can now amplify everything, without risking distortion or clipping. This has the overall effect of the music sounding louder. In our example, an output amplification of
5 dB would be okay, if the input signal never exceeded
0 dB.
Authors: Matthias Kretz, Stefan Westerfeld
License: GNU General Public License
Channels:
| audio-in1: | |
Audio input 1 |
| audio-in2: | |
Audio input 2 |
| audio-out1: | |
Compressed audio output 1 |
| audio-out2: | |
Compressed audio output 2 |
|
Properties:
| attack: | |
Set the attack time in milliseconds (Range: 0.1 .. 250) |
| release: | |
Set the release time in milliseconds (Range: 0.1 .. 250) |
| threshold_db: | |
Only parts louder than threshold are compressed (Range: -100 .. 0) |
| ratio_to_one: | |
Set the compression ratio to x:1 (Range: 1 .. 20) |
| output_db: | |
Set the output amplification (Range: -20 .. 20) |
| auto_output: | |
Adjust the output amplification automatically according to threshold and ratio |
|
