One of the most misunderstood features of the Auto Filter is the Envelope section. I’m gonna show you a couple of fun things to do with it, but first you’ve gotta know how it works.
The Envelope section is used to detect the volume of the incoming signal and use it to control the filter’s cutoff frequency, like a classic envelope follower such as the Mu-Tron. To get started with this feature, first pull the cutoff frequency down until the source signal sounds a bit too filtered, then crank up the Envelope knob.
It’s also a good idea to make sure the LFO Amount is at zero. You can use the Envelope and the LFO simultaneously, but until you’re a filter master it can get a bit confusing.
The trick to understanding the Envelope section in action is that you’ll only get interesting results out of it if you use it on a fairly dynamic signal. An extremely dynamic signal is even better. Try it on a percussion loop with loud hits and soft hits, or better yet, plug a guitar or bass into Live and play right through the Auto Filter. (Warning! You may start to think you’re Bootsy.)
Set up like this, it should be easy for you to hear the dynamics controlling the cutoff frequency. Adjusting the Envelope knob will change how much the cutoff frequency is modulated. For more extreme effects, crank it higher, and turn down the cutoff frequency. To be more subtle, use a low Envelope amount and leave the cutoff frequency somewhat higher.