[sdiy] 4-pole SVF theory

[karl dalen]

>David G Dixon <dixon at mail.ubc.ca>

>>> Pleez, help me edukate meself!
>>First, learn to spell!
 
> So, I guess that course in "Internet Etiquette"
> at the local Kom Vux was full, eh?  :)

Yes, you and Neil had taken the two last seats. :) 

>You keep creating feedback gain matching the pole polynomial
>you want to create.You keep creating feedforward gain matching
>the zero polynomial you want to create.

>The booring detail is this... for variable Q setups the polynomials can 
>get messy, unless you try to create a simple polynomical matching that 
>of a normal lowpass-filter with a feedback for Q. So adapting to 
>"musical" filters needs a bit of care. 

>State-variables are neat for the theorists, as it allows for simple 
>mapping of polynomials to filter synthesis. This does not necesserilly 
>make it neat for musical use.
>Cheers, Magnus.

Amen to that, and that's why Neils 3pole sounds so lame Mr Dixon. ;)

KD