envelope follower

[stoPpa]

can someone explain for me what a envelope follower is, and what it does to the sound.
sincearly
Christopher

[CinningBao]

by itself, I'm not sure an envelope follower will do much at all, but in a filter it can by used to track the amplitude to regulate the filter, and voila! you have an auto wah!

essentially, an evelope follower will follow the amplitude of the audio signal which can then be used to control effect parameters, like the phase depth in Bram SupaPhaser
http://www.kvraudio.com/get/970.html

does that help?

[kylen]

Blue Cat has a type of envelope follower you can use to generate envelope points to later control any aspect of an audio track (in a host that supports it like Sonar) - volume, pan, aux send levels, effect params, etc. all based on the peak levels program content.

http://www.kvraudio.com/get/1357.html

It does not modify the sound of the audio itself - just allows you to modulate it by controlling transformations later.

[Panda]

An envelope follower extracts envelope characteristics from one wave and thus enables you to apply them to others in ways described above, and many, many others.

[emdot_ambient]

kylen is correct. An envelope follower looks at the amplitude of the audio fed into it and ouputs a control signal; it doesn't actually alter the original audio.

Originally this was on analog voltage controlled systems and the output was a continuously variable voltage that could be pointed at any VC device. So really it could use the amplitude of the input audio signal to control the pitch of an oscillator, the frequency modulation of a filter, the amplitude of an amplifier . . . or modulate any voltage controlled device. Often they were coupled with a gate/trigger signal set to fire off once a particular threshold amplitude is reached. So basically at that point it becomes a hyper envelope generator.

[stoPpa]

thanks for your replys, it really help me
christopher

[P.T.]

So, what are some envelope followers that we can try out?

[kylen]

So, what are some envelope followers that we can try out?

For audio Blue Cat Digital Peak Meter (free)

[Hermetech Mastering]

the only standalone one i know of is the one in the mda set, and it's pretty damn good. you can use it to do stuff like extract the amplitude from a drum loop and apply that to a pad for gated effects, or even delay its output and use it to effect the amplitude of the original loop for weird ryhthmic compression/expansion effects.

a lot of other effects have envelope followers built in, such as the aforementioned phaser from smart electronix, the phase shifter from ohmboyz, and the new classic filter from torben.

[kylen]

...or even delay its output and use it to effect the amplitude of the original loop for weird ryhthmic compression/expansion effects.

Now we're talking - adjusting the latency in Sonar4 causes the envelope to be written early so that, in effect, I have an envelope that predicts the future.

a lot of other effects have envelope followers built in, such as the aforementioned phaser from smart electronix, the phase shifter from ohmboyz, and the new classic filter from torben.

Voxengo compressors like Polysquasher (I think) and Soniformer have envelope follower detectors (as opposed to peak or sample detection) although Soniformer has a peak detector also. The point being thaere seems to be a good use for envelope followers in compressors also - that would tend to average out or smooth the response I would think. Polysquasher can be fast when it needs to though but I think there's some extra program dependent stuff in there too that adjusts attack/release.