18 Jul
2011
18 Jul
'11
12:57 p.m.
David Adler wrote:
On Mon, Jul 18, 2011 at 12:13 PM, Renato wrote:
Do not confuse DAC/ADC bit width with bit widths used during DSP
calculations. The two are basically orthogonal.
On Mon, 18 Jul 2011 11:53:47 +0200
...
isn't it useless going way above 24 bits,
since that's what in the end
the DAC (sound card) will use? as far as I can remember, delta-sigma
DACs don't go over 24 bit, do they?
More than 24 bit for DAC/ADC is useless, going above 24 bit for
internal processing is not. The latter ensures that rounding errors
that may be introduced by multiple math operations disappear when bit
depth is finally reduced again to 24 before entering the DAC. The magnitude of rounding errors depends on the type
and number of
operations done. I don't know the limits, but for what Fons calls
"normal audio engineering practise" (see his posting above), 32 bit is
enough.
For audio data paths this is true. For the intermediate results
during complicated calculations (eg filters and reverbs) double
precision makes things easier and is basically available for free.
Erik
--
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Erik de Castro Lopo
http://www.mega-nerd.com/