If you have the equations, it should be possible, in general,
to code them in Csound.

I'd have thought guitar amp simulators would use convolution
with measured IRs of the various 'modelled' amps.

Victor
----- Original Message ----- 
From: "Darren Landrum" 
To: 
Sent: Saturday, January 19, 2008 7:40 PM
Subject: [Csnd] Re: Re: Circuit modeling in Csound?


> victor wrote:
>> Don't know much about analogue electronics, but things like
>> digital filters etc can be easily modelled
>> with just arithmetic in Csound.
>
> That's not really what I'm looking to do. I'm actually trying to simulate 
> the physics of electronics components in software (or at least, what they 
> do to sound), and then building virtual circuits for processing or making 
> audio. This is how most of the various guitar amp simulators on the market 
> work, for example. Some analog softsynths also work in this manner.
>
> Thanks for the reply!
>
> -- Darren Landrum
>
>
> Send bugs reports to this list.
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe 
> csound" 

victor wrote:
> If you have the equations, it should be possible, in general,
> to code them in Csound.
> 
> I'd have thought guitar amp simulators would use convolution
> with measured IRs of the various 'modelled' amps.

Well, that's certainly one way to do it, but it can't be parameterized; 
Your amp sim sounds the way the amp did at those knob settings, and the 
only way to get other settings is to take more IRs. I suppose there are 
tricks that can be done, like cross-fading IRs, but I don't know how 
well such ideas work in real-time. Also, distortion effects (which is 
the addition of previously non-existent harmonics) aren't really 
convolution's strong suit, IIRC (filters aren't good at adding new 
harmonics is how I understand it).

Waveshapers are one simple trick, and tweaking some different non-linear 
shapers can begin to sound close to various tube amps. Add in an IR 
response for the *cabinet* (rather than the amp) and you can get some 
decent sounds.

Of course, the DSP experts on this list will probably point out where 
I'm wrong, and I'm only happy to expand my education. Thanks, all!

-- Darren Landrum

As a related aside, does anyone know or have a link to a site that might 
explain how to convert an incoming digital audio stream (32 or 64-bit) 
into a voltage/current representation? Those are the numbers most of 
these component models like. Thanks!

-- Darren Landrum