On Sun, May 26, 2013 at 10:33:23PM -0400, Michael Gogins wrote:
> That is fine with me. I think the documentation should say:
> 
> 0dBFS is 0 decibels (maximum amplitude) at full scale. As always with
> decibels, which are a relative measure of energy, 0 dBFS is a nominal
> value.
>
> [.....]

I like that clear exposition, but maybe that should replace the slightly
later 'decibel' paragraphs in the "Amplitude Values in Csound" section.
I attempted a rewrite of the introductory one as:

"Amplitude values in Csound are always relative to a "0dbfs" value
representing a specified "0 decibel full-scale" peak amplitude. When
the final output from Csound will be some integer-sample format with
a strictly defined range (for example, WAVE or AIFF), this value also
represents an absolute level above which samples will be clipped. The
stream is also rescaled to match the actual range of the format. When
the output is in floating-point, as will usually be the case for live
audio in current systems, signals are not clipped, as floating-point
itself has no hard limit; rather 0dbfs is the signal amplitude which
will be rescaled to the standard sample value '1.0' for the output stream.

In the original Csound, this limit value was fixed at 32767, corresponding
to the bipolar range of a 16bit soundfile or 16bit AD/DA codec, Csound's
only possible output back then. This remains the default peak amplitude
for Csound, for backward compatibility and you will find some of this
manual's examples still use this value (hence you find large amplitude
values like 10000)."
...

Then for the "0dbfs" page:

"Amplitude values in Csound are always relative to a "0dbfs" value
representing the peak available amplitude. For integer output, this
is also the clipping point; with floating-point there is no clipping,
so it just represents the intended limit."

... or something like that.

	-- Pete --


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