MB>> Well, the A/D/S/R formulas were invented in the 70's/80's I think, and
 MB>> because digital synthesizers had quite poor math for quite high prices,
 MB>> it was much easier to use linear equations rather than exponential
 MB>> ones.
 SX>   Hmm... actually, I've been thinking of designing a new music format 
 SX> based on
 SX> this. I'm planning to write up a design doc sometime soon when a little 
Hmmm, there are already the ROL format and the CMF format.
 MB>> A real guitar string sound would only have an A and a D: the A is the
 MB>> kind of noise you get by rubbing a finger or a pick on the string, and
 MB>> the D is a e^-kt envelope equation.
 SX>   Hmm... yes. Wouldn't there be a brief sustain, too? If you rubbed your 
 SX> finger
 SX> for some distance, that is?
According to my description, the attack on a guitar string isn't a
linear ramp-up envelope. I think it rather looks like an
almost-constant envelope. When the "real sound" starts to play at the
beginning of the decay part, there starts the ce^-kt thing. the "c"
here is a constant, the initial volume of the decay. Note that this "c"
might be different from the volume level of the attack.
so, say "a" is the length of the attack and "n" the attack volume:
for ta play tone at volume A(t) = c e^-k(t-a)
if n=c, volume of attack is same as initial volume of decay.
Does it clarify that a longer rubbing only is a longer attack, and the
D/S/R part of a sound is only one physical phenomenon on a guitar
string?
Matju 1:243/68.1 101:163/100 34:104/103 http://www.comnet.ca/~galois/matju/
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