Re: 64bit processing - Why?
Re: 64bit processing - Why?
- Subject: Re: 64bit processing - Why?
- From: James Chandler Jr <email@hidden>
- Date: Fri, 31 Jul 2009 00:45:13 -0400
On Jul 30, 2009, at 11:51 PM, Brian Willoughby wrote:
There are, however, emerging converters which claim 30-bit or 32-bit
performance, but their techniques are not necessarily high-quality.
It does present the possibility that we may soon desire to go beyond
24-bit precision when passing data from host app to hardware.
Today's 32-bit DACs are questionable, but perhaps we're right around
the corner from something which truly goes beyond 24-bit.
Another decent reason for wide dynamic range is that not all audio is
mastered up to the ceiling. If playing back a -20 dB peak signal, and
the listener has turned up the playback system to compensate, then the
bits at the bottom become more important.
Long ago had read that DAC noise floor is not only limited by analog
noise-- thermal, shot, flicker noise. But it was also very difficult
to make the DAC linear down to the 24th bit. A DAC linear down to 24
bits would require accuracy better than 1 part in 16.7 million or
whatever, which was said to be a very difficult trick.
And of course if the linearity of the low 4 bits happens to be no
better than 'the luck of the draw', then that 4 bits of random hash
applies to all signal levels, not just the very quiet signals.
But time marches on and it will be interesting if >24 bit DACs claim
(and achieve) linearity down there.
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