Re: Convolution: How much CPU needed?

[andy butler <akbutler@tiscali.co.uk>]

van Sinn wrote:

> Which leaves by far the worst CPU hog: Convolution, but how much ?

Depends on how large a sample you want to use.
Charles is right it's a very simple operation,
indeed your 31 band eq will likely use convolution as
the most efficient way to do the filtering.
 
...but 
there can still be an awful lot of work for the processor to do.
The eq is only going to have something like 1024samples to
calculate.

I'm using a dual core 3GHz intel machine and
it just took 15s to convolve a 1 minute file 
with a 5s stereo sample.

So..if I was running it real time (which I wasn't)
it seems reasonable to equate that with 25% use of resources.
...and an equally rough calculation says that a 20s stereo sample
would be the absolute limit for real time convolution on my machine.

...which suggests that if you want to use the convolution for a 
long reverb you might run out of processing power.

Maybe if you're more revealing about what you want the convolution for
then someone whose actually got experience will be able to give you
some better info.

andy butler