Nice. Thanks Chuck, I learnt something. On 22 April 2015 at 23:45, Charles Z Henry <[email protected]> wrote:
> On Wed, Apr 22, 2015 at 5:11 PM, Alexandre Torres Porres > <[email protected]> wrote: > > > So I start with this idea that the audio (values from -1 to 1) can't be > in > > full 32 bit float resolution, it's less. I don't see why that is "wrong". > > And then, from it, my first question here was: "what is the audio > resolution > > then?". I'm still clueless here about this answer. > > > > Moreover, is it more or less than what 24 bit audio cards handle? > > Let me try: > > 32-bit floating point numbers have 24 bits of precision. Always. The > remaining 8 bits are just for the sign and exponent. When the > amplitude of the signals decrease, you don't lose any precision in > floating-point. The value of the least significant bit (LSB) gets > proportionally smaller. > > However, the output of a 24-bit soundcard always has a fixed > quantization. The LSB is always the same size. Smaller numbers have > less precision. > > The mismatch occurs when converting from the 32-bit floats to the > 24-bit fixed point numbers. Now, the smaller numbers aren't as > precise anymore. They get rounded to the nearest number in the 24-bit > fixed point system. > > So, yes, the resolution (of small numbers) in floating point (internal > to Pd) is finer than the resolution of those numbers when output > (driver/DAC). > > Also, the 24-bit fixed point format is for values between -1 and 1. > That means that numbers between 0 and 1 have just 23 bits. In 32-bit > math, the numbers between 0.5 and 1 still have 24 bits of precision > (the sign is held elsewhere). That means that Pd's internal > resolution is finer than the soundcard resolution for all numbers > between -1 and 1. > > Chuck > > _______________________________________________ > [email protected] mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list >
_______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
