[PD] why do [bp~] and [vcf~] sound different?

[Ichabod]

On Tue, Jul 14, 2009 at 8:32 AM, cyrille henry
<cyrille.henry at la-kitchen.fr>wrote:

>
> source code for both object look really diferent, so i don't know if it is
> possible.
> but seriously : why do you need to replace vcf~ with bp~???
>
> Cyrille


I wouldn't say I *need* to, I'd just like to... Here's an example: I was
making a composition that used a choral pad with vcf~ objects acting as
movable formants.  I decided I only really need the voices to sing "aaaaah,"
so I realized I don't need the movable formants after all, so I can
economize on CPU by using static bandpass filters rather than moving ones.
I've never seen anything about differences between the filters' internal
math, so I was surprised to find that they sound different.

So basically what I want to know is: if I have a vcf~ with a given q and
constant center frequency, is there a way to replace it more cheaply?

--Stefán
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