Subject: Re: [linux-audio-dev] LADSPA 64bit FP support ?
From: James McCartney (asynth_AT_io.com)
Date: Wed Mar 22 2000 - 08:03:20 EET
on 3/21/00 11:01 PM, Paul Barton-Davis at pbd_AT_Op.Net wrote:
>> You are mixing up terms here. 32 bit FP has 151 bits of dynamic range
>> (=log2(FLT_MAX/FLT_EPSILON)), but only 24 bits of signal to noise. You don't
>> need as much SNR as you do dynamic range. Most manufacturers of digital
>> equipment mix up these terms as well in their published specs. A 24 bit int
>> signal has 24 bits of SNR, but the dynamic range depends on the amplitude of
>> the signal. With FP the dyanamic range doesn't depend on the amplitude for
>> any practical purpose.
>
> Can you explain this some more ? How can the dynamic range of a 24 bit
> int be dependent on the amplitude of the signal, when the FP one is
ACK! Sorry. In my attempt at explaining I myself reversed the terms.
That should read:
"A 24 bit int signal has 24 bits of dynamic range, but the SNR depends on
the amplitude of the signal. With FP the SNR doesn't depend on the amplitude
for any practical purpose."
In other words the quieter an integer signal becomes the less SNR there is.
Floating point signals do not lose SNR as they become quieter.
--- james mccartney james_AT_audiosynth.com <http://www.audiosynth.com>
SuperCollider - a real time synthesis programming language for the PowerMac.
<ftp://www.audiosynth.com/pub/updates/SC2.2.7.sea.hqx>
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