On Tuesday 04 April 2006 11:50, [EMAIL PROTECTED] wrote:
> > On Tuesday 04 April 2006 09:36, Erik Hofman wrote:
> >> Timothy Miller wrote:
> >> > On 4/3/06, Justin Findlay <[EMAIL PROTECTED]> wrote:
> >> >> I'd say more than 24, perhaps 32 bits per channel.
> >> >
> >> > Ok.  I thought about saying 32, but I didn't want to look absurd.  :)
> >>
> >> Internally you would have to use 32-bit floating point values,
> >> everything else will be obsolete rather soon. 24-bit D/A conversion
> >> would be nice and  32-bit D/A converters would be great.
> >> Or forget about an internal D/A converter all together and use digital
> >> output only.
> >
> > There are problems associated with 32bit floating point signal processing
> > in
> > audio especially if you are trying to do DSP on the card. The easiest
> > example
> > of this is low freqency/high Q filtering which needs simultaneous use of
> > large and small values, something floating point is not good at. A double
> > precision 24bit fixed point DSP would be much better. You get a dynamic
> > range
> > of 288dB plus more predictable results from your algorithm.
>
> What is "double précision 24 bits DSP" ?
>
> 32 bits flotting point unit use 24 bits mantissa. The precision is the
> same as a 24 bits fixed integer unit. So i don't understand you're point.
>
As I understand it you basically pair 2 x 24bit DSPs to give yourself a 48bit 
fixed point DSP. 

The benefits are explained here. 
http://www.jamminpower.com/PDF/48-bit%20Audio.htm

I know it would be more expensive but considering that the ear is very 
sensitive to "pumping" of audio I think it would be worth it if you were 
going to be doing filter on the card and selling it as a pro-audio card.

Regards,

Paul Mullen.

> Nicolas Boulay
>
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