Envelope Followers And Filter

[AzzR]

Can anyone tell me the exact difference between an envelope filter and an envelope follower

Thanks
DreamSeller

[RickL]

The short answer is that there isn't any.

More correctly, an envelope follower is an electronic circuit that derives a voltage that is proportional to the strength of the signal that goes into it. Loud guitar signal gives high voltage, soft signal gives lower voltage. This voltage can then be used to control some other circuit, for instance a filter, but it can be any number of things.

What is typically called an envelope follower or envelope filter is more properly called an envelope controlled filter. When the input signal is loud the cutoff frequency of the filter is high, as the signal dies down the cutoff frequency goes down. Or high input could give low cutoff and low input give high cutoff.

If the EF (envelope follower) is used to control gain (high input gives lower gain, low input gives higher gain) you have a compresser. EFs can be used to control any number of parameters with cool results.

Craig Anderton gives a great explanation of envelope followers in Electronic Projects for Musicians.

[Mark Hammer]

Actually, I thought yours was pretty good, Rick.

(BTW, you DID complete your employee survey form, didn't you?  I need that data.  )

[ragtime8922]

The short answer is that there isn't any.

More correctly, an envelope follower is an electronic circuit that derives a voltage that is proportional to the strength of the signal that goes into it. Loud guitar signal gives high voltage, soft signal gives lower voltage. This voltage can then be used to control some other circuit, for instance a filter, but it can be any number of things.

What is typically called an envelope follower or envelope filter is more properly called an envelope controlled filter. When the input signal is loud the cutoff frequency of the filter is high, as the signal dies down the cutoff frequency goes down. Or high input could give low cutoff and low input give high cutoff.

If the EF (envelope follower) is used to control gain (high input gives lower gain, low input gives higher gain) you have a compresser. EFs can be used to control any number of parameters with cool results.

Craig Anderton gives a great explanation of envelope followers in Electronic Projects for Musicians.

I was all ready to answer this question until I read Ricks explanation. Nice job Rick!

[RickL]

Aw gorsh thanks. I was mostly just paraphrasing Craig.

And yes Mark, I did complete the survey. Didn't you recognize my typing style?