[sdiy] AR, AD envelopes

[Scott E.]

Tim,

I can't recall where, but I have seen AR circuits with what I remember 
to be a "Free run" option where it will complete the attack cycle 
regardless of the presence of the gate voltage. It would sustain only if 
the gate signal were present after the attack portion had finished. I'll 
look around to see if I can find where I saw this.

Regards, Scott
=============================================================
Tim Parkhurst wrote:

> Hi All,
> 
> Okay, this should be a stupid simple question, but I want to make sure I've
> got it correct in my mind. The more I thought about it, the more I realized
> I wasn't 100% sure. Basically, I'm trying to straighten out the differences
> between AR and AD envelope generators. Here's what I've got...
> 
> AR Envelope: Attack cycle begins when gate signal goes high. If the gate
> signal goes low before the Attack cycle has completed, the envelope will
> immediately jump to the Release cycle. If gate is still high when Attack
> cycle is complete, envelope remains at peak level until the gate goes low,
> at which time the Release cycle begins. 
> 
> AD Envelope: Attack cycle begins when gate signal goes high. The attack
> cycle completes and then the envelope goes to the Decay portion regardless
> of the status of the gate signal.
> 
> Is this correct? Is there a need for an AD/S (Attack, Decay with Sustain)
> envelope? In this one, the attack cycle would complete, the envelope would
> remain at peak level as long as the gate signal was high, and then go to the
> Decay cycle as soon as the gate went low (this is a little different from
> the AR envelope in that the Attack cycle would always finish, even if the
> gate goes low before the Attack is complete). 
> 
> Again, this should be butt-simple stuff, but I just wanted to make sure. I'm
> laying out a simple little EG, and I was curious as to whether the extra AD
> and AD/S modes would be worth it. I await your comments, wisdom and insults.
> 
> 
> Tim (sweating the details) Servo
> 
> "Imagination is more important than knowledge." - Albert Einstein
> 
> 
> 
> 
> 
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