On 2/22/07, Tim Orford <orford@xxxxxxxxx> wrote:
On Thu, Feb 22, 2007 at 04:04:34PM -0500, Paul Davis wrote: > On Thu, 2007-02-22 at 15:53 -0500, Rick Wright wrote: > > > This is true, but as Folderol wrote, 32 bits should be *plenty* of > > dynamic range for audio. In fact, it has been argued that ~22bits is > > sufficient as beyond this you get into the h/w noise floor, hearing > > limits, etc. > > 32 bits of resolution gets you close to the *thermal* noise floor. i.e. > your recording contains noise contained by brownian motion. not very > useful. Unfortunately digital processing has completely different set of problems than analogue. 32 bit seems to be plenty for us mere mortals with more practical problems, but I wouldnt dismiss the esoteric benefits of increased resolution for complicated processing tasks so easily when quality is the prime concern. The maths is very tricky.
Yes, in my experience 32-bit audio isn't necessary for listening so much as it is for processing. Csound is available with 32- or 64-bit calculations, and the usual recommendation is to use 32 for composing and producing and making all decisions, and 64-bit for final rendering, simply because, if you have a dozen or so filters all making little round-off errors, sine wave tables that are accurate to so many bits all being scaled and time-shifted, Fourier transforms converting from time to frequency representations, and a thousand other things being calculated and rounded off, having twice the bit depth could change the final outcome, even if the eventual delivery method will be 16 bits. I'm sure it's the same idea with graphics. BTW, I thought 24-bit graphics were sometimes implemented as 32-bit, with an alpha channel? What a brilliant idea. I wouldn't make the comparison, though, that 48 bit graphics is like 16 bits with 3 channels, because I don't see red, green, and blue separately. If you change the value in one channel, I don't say "hey that looks bluer, but about the same red and green", I say "It's a different color". -Chuckk -- http://www.badmuthahubbard.com
