Re: Convolution: How much CPU needed?

[van Sinn <vansinn@post.cybercity.dk>]

andy butler wrote:
> 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

Thanks Andy, Per and Charles.
My bad - I should of course have stated the convolution purpose..
It's for running impulses to emulate the guitar amp/speaker/mic chain.


Further, thinking back on theory on digtal signal processing, I agree on 
how compute intensive digital filters can be; should've used my brain ;)
This part can of what the computer is intended to be used for can be 
left out if need be; it's more on the wish list than strict requirement.


-- 
rgds,
van Sinn