[LAD] FULL audio-signal path

Paul Davis paul at linuxaudiosystems.com
Sun Jul 22 17:29:19 UTC 2007


On Sun, 2007-07-22 at 10:48 +0100, Dan Mills wrote:
> On Sun, 2007-07-22 at 09:45 +0100, Steve Harris wrote:
> > On 21 Jul 2007, at 13:56, Dan Mills wrote:
> > > Be very careful how you write float->int conversions (it is not
> > > trivial), and work in floating point as far as is possible, there is
> > > little reason (other then marketing) to move to doubles (IIR filters
> > > possibly excepted).
> > 
> > Well, I'd qualify that as there's no need to use doubles between  
> > modules, there are many DSP processes that work better in double if  
> > you can afford the extra memory bandwidth. Filters are one.
> 
> Granted. 
> 
> > It's generally not doubles in the audio path though, but its things  
> > that you're using to modify it, coefficients, phase accumulators and  
> > so on.
> 
> I was thinking mainly about some commercial DAWs that boast of stupid
> word length accumulators for mix buses and the like. I never did
> understand that.  

1) the ones that do are using fixed point math, not floating point
2) there are some good theoretical arguments for needing more than 32bit
floating point resolution for a mixer

--p





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