[Fpga-synth] Envelope - linear attack & expo decay/release?

[Eric Brombaugh]

Scott Gravenhorst wrote:

> My GateMan synths, both poly and mono use linear slopes for all of the ADSR phases.  I
> did not perceive abrupt changes in my envelopes - is it a matter of degree?  I.e., how
> long of a release are you doing that this is noticable?

I'm talking release times in the > 2s range. The sort of thing you might 
use for a bell or an open guitar string. The effect is like someone 
damped it down at the end rather than letting it ring on.

> I believe that analog ADSRs are usually exponential since they are a simple single
> pole RC circuit allowed to charge or discharge through a resistor.  When I did my
> GateMan design (the first one) I considered expo, but first tried linear because it
> was simpler.  Having not noticed a problem, I went no further.

I agree with your origin theory, and I had the same approach - linear is 
easy so try that first. I'm starting to think that expo is necessary for 
the best dynamics in some situations though. It's gonna need another 
multiplier - good thing I've got a few to spare.

Eric