[LAD] simulating analog audio devices part II

Robin Gareus robin at gareus.org
Thu Jun 7 10:05:38 UTC 2007



Stefano D'Angelo wrote:
> Il giorno gio, 07/06/2007 alle 09.20 +0200, Robin Gareus ha scritto:
>> Stefano D'Angelo wrote:
>>
>>> Hi,
>>> I read on spicy sound website: "However todays computing power allows to
>>> do so almost in real-time!"... do you think you'll get it real-time?
>> no, not any more.
>>
>> Without oversampling, small circuits run /almost/ in real-time. However
>> the posted 3 seconds of guitar took almost 4 mins to be processed with
>> ngSpice simulating at 1s/(64*48k) timesteps.
> 
> 4 mins? OMG! :-\

indeed - at least it scales linearly with decreasing timesteps ;) - for
guitar a *8 or *16 oversampling is sufficient. ngSpice is clearly is not
suitable to be used as audio-effect; yet it's handy to test&debug
audio-circuits, or even create convolution samples.

Does anyone here have access to the full version of
http://www.acusticaudio.com/modules.php?name=Products&file=nebula2free
VST plugin? - It would be interesting to know if ngSpice-snd samples can
be used to program it.


nudged by Erik at
http://linuxaudio.org/pipermail/linux-audio-user/2007-May/045899.html
I've Taylor-expanded a convolution integral, and started to look for
some papers. The maths is not too wicked after all; but coding a
volterra transfer function best with CPU optimization is no laughing
matter.. - I've chatted with a physicist friend who has access to some
pro-maths software to crunch integrals and product series and experience
doing so - I'm gonna spend a few weeks with Florian during the summer
and 'll get back to you guys. ATM my ToDo list is way too overloaded and
just glimpsing at bruteFIR or aliki: this is no small project either!

robin



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