Re: 64bit processing possible?
Re: 64bit processing possible?
- Subject: Re: 64bit processing possible?
- From: Brian Willoughby <email@hidden>
- Date: Thu, 30 Jul 2009 15:14:49 -0700
On Jul 30, 2009, at 15:04, David Duncan wrote:
On Jul 30, 2009, at 2:56 PM, Brian Willoughby wrote:
To pick a nit, though, there are plenty of audio hardware devices
which can use all 24 bits of precision. 32-bit float actually has
25 bits of precision when you include the implied "1" bit in the
mantissa, and thus it's true to say that no audio hardware can
make use of all 25 bits of available precision. I'll assume this
was just a typo below.
32-bit floats have 23 bits of mantissa (8 exponent, 1 sign). The 24-
bit precision already includes the implied leading 1.
Oops. I swear that I saw a table of standards which listed 24 bits
for the mantissa, but perhaps that table already included the implied
leading 1. In any event, every reference I can find today says that
it is 23+1, so I was clearly mistaken.
In light of that correction, then I will say vehemently that there
are several audio interfaces which make full use of all 24 bits of
precision. Perhaps Bill is thinking about the analog noise
specifications, which do not match the potential 144 dB of dynamic
range that could be possible. However, the presence of analog noise
is not exactly equivalent to a lowering of the bit depth, since
digital quantization noise is perceived differently by the human
hearing system than the analog noise. In other words, audio still
needs to make use of all 24 bits that are available, even if the
overall dynamic range is barely over 110 dB or 120 dB.
Brian Willoughby
Sound Consulting
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