Along with an alternative, I have some comments to the solutions above that suggest using the dysoncompressor.
From the manual:
2.37 Dyson compressor (dysonCompress, 1403)
Peak limit (dB)
Controls the desired limit of the output signal in dB's.
Release time (s)
Controls the time taken for the compressor to relax its gain control over the input signal.
Fast compression ratio
I have no clear idea what this controls.
Compression ratio
I have no clear idea what this controls.
http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#tth_sEc1.1
The author of the package doesn't know what the last two values control. So how could you all say what you should input as the last two values?
The plugin itself suggests control=0,0.25,0.5,0.5
$ analyseplugin /usr/lib/ladspa/dyson_compress_1403.so
Plugin Name: "Dyson compressor"
Plugin Label: "dysonCompress"
Plugin Unique ID: 1403
Maker: "Steve Harris <steve@plugin.org.uk>"
Copyright: "GPL"
Must Run Real-Time: No
Has activate() Function: Yes
Has deactivate() Function: No
Has run_adding() Function: Yes
Environment: Normal or Hard Real-Time
Ports: "Peak limit (dB)" input, control, -30 to 0, default 0
"Release time (s)" input, control, 0 to 1, default 0.25
"Fast compression ratio" input, control, 0 to 1, default 0.5
"Compression ratio" input, control, 0 to 1, default 0.5
"Input" input, audio
"Output" output, audio
I would even suggest that you try one of the other compressors, that seem better documented, like sc4.
load-module module-ladspa-sink sink_name=ladspa_sink plugin=sc4_1882 label=sc4 control=0,101.125,401,0,1,3.25,0