Is there a difference between LPG and envelopes?

[deeplink]

Sorry for the weird title but couldn't think of a short way to put this:

Does using an LPG (like in Complex-1) achieve the same effect as,
sending one envelope to both the Amp and Filter?

Is there a sublte but important difference?

[Jackjackdaw]

That's the basic principle. But a hardware LPG has a vactrol inside it which I presume the software tries to emulate the behavior of.

[eXode]

Sorry for the weird title but couldn't think of a short way to put this:

Does using an LPG (like in Complex-1) achieve the same effect as,
sending one envelope to both the Amp and Filter?

Is there a sublte but important difference?

You kind of mixed the meaning when mentioning envelopes but in short:

A LPG (Low Pass Gate) is basically a combination of a VCA and a VCF, but you can often switch the behavior on a LPG to act either as a
VCA, VCF, or Both.

The LPG comes from the west coast philosophy of modular synthesizers like Buchla and Serge. The filter in the LPG has a roll-off of 12dB/octave (i.e. it's like a 2-pole filter) if I remember correctly. Like Jackjackdaw mentions, a hardware LPG is built from vactrols that contribute to it's characteristic sound.