Subject: Re: [linux-audio-dev] [ann] unmatched - a LADSPA amp tone
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Mon Oct 28 2002 - 19:47:49 EET
On Mon, Oct 28, 2002 at 05:53:26 +0100, Tim Goetze wrote:
> >make interesting non-linear filters by using different parameters for the
> >different halves of the wave cycle. This is what makes the gong sound
> >gongy (waveguide_nl.h). It could also apply to cone modelling, as the
> >characteristics of the deflection in the positive and negative directions
> >will be a bit different.
>
> it's interesting to know that valve preamp stages should have
> a small bias (to + iirc), and you can in fact observe this in
> the amp output i've recorded.
That is a side effect of class B amps IIRC. I would have though that
preamps would be class A, but maybe not.
> i'm still trying to model the hard-driven valve in the time
> domain. the more i look at it, the more i think the 'building of
> potentials' i've tried to describe comes near it. though it would
> be nice to base it on hard facts about valve amp behaviour, too.
'building of potentials'? Are you refering to your sinc summation idea?
Its a nice idea, especially as you get anitaliasing for free, but I think
it will be hard to turn a hardish clipping shape into a sum of sincs.
> interestingly, the sine, shaped by the hard-driven amp, looks
> a lot like the plots of 'ion conductivity' and 'Aktionspotential'
> from human heart analysis.
Woooosh. [that was the sound of that going way over my head ;) ]
> >Different amplitudes would be equivalent to how you model nonliear systems
> >with FIR impulses - I can't believe I didn't think of it before.
>
> in fact you described something along these lines a few days
> ago. ;)
Er, did I? Right. Maybe more sleep would be good ;)
- Steve
This archive was generated by hypermail 2b28 : Mon Oct 28 2002 - 19:56:22 EET