Muff's Modules & More

dvdborn · Posted: Mon Mar 05, 2012 7:40 am Post subject: Patching up a compressor

How would you create a patch that has the functionality of an audio compressor?
Extra points for adding a side chain to input to it.

Stereotactixxx · Posted: Mon Mar 05, 2012 8:13 am Post subject:

For a traditional feed forward VCA comp:

You need two signals, one is the audio you want to compress, and the other one either a duplicate achieved by a splitter or multiple, or our side chain signal. The audio you want to compress goes straight into the input of the VCA. The other signal is used to create a CV for the VCA:

Run it through an envelope follower. Add a negative offset (threshold). Kill the negative part of the signal so that it only consist of positive voltage. Run it through a slew limiter with separate attack and release. Invert the signal. Attenuate (Ratio). Add +5V or what ever you need to fully open up the VCA. Use signal to control VCA.

Haven't tried it, but it should work.

EDIT: had a brain fart and wrote slope detector, but what i meant was envelope follower. Changed it.

Zenn · Posted: Mon Mar 05, 2012 8:20 am Post subject:

For sidechain, plug your audio into the VCA Audio in, sidechain signal into the input-in.

*) VCA should be an exponential vca. my bad

Fnord · Posted: Mon Mar 05, 2012 8:29 am Post subject:

Check out Babaluma's classic post on this topic
http://www.muffwiggler.com/forum/viewtopic.php?p=81690

Babaluma · Posted: Mon Mar 05, 2012 8:55 am Post subject:

thanks fnord, i was also gonna post that link! i miss the VCS/Boogie compressor combo... waah

dvdborn · Posted: Mon Mar 05, 2012 9:03 am Post subject:

Thanks for the info and the topic link.