[LAD] panning thoughts

Ralf Mardorf ralf.mardorf at alice-dsl.net
Sat Nov 13 17:51:17 UTC 2010

On Sat, 2010-11-13 at 16:26 +0100, fons at kokkinizita.net wrote:
> On Sat, Nov 13, 2010 at 02:57:44PM +0000, Folderol wrote:
> > Paul Davis <paul at linuxaudiosystems.com> wrote:
> > 
> > > there's an awful lot of math for which a modern processor can compute
> > > the answer faster than it can look it up. this is one such example (as
> > > fons noted), but there are many others. this started changing about 8
> > > years ago, and its only gotten more true since then.
> > 
> > Oh dear. I didn't realise I was so far out of date :(
> It's absolutely true. 
> Note that the calculation I posted earlier runs entirely on
> the FP processor, and two variables, q and d, will probably
> only exist there and never be written to memory. If it takes
> any time at all, the CPU can meanwhile do something else,
> such as getting the pointers to the audio data it will need
> later. Using a LUT will mean the CPU has to do all the work,
> which includes getting the base pointer and calculating the
> required offset(s).
> Ciao,

Just to ensure you aren't talking about different claims.

Is math even faster, as e.g. 4 states for left, 1 for centre and 4
states for right, provided e.g. by an array? Or are you thinking about
nearly stepless panning?


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