YES! Finally,... I was waiting for someone to mention that.

Where does the 96dB come from? 

It comes from the idea that, in the the "Ideal" digital world,...

1-bit of digital audio data= 6dB of SNR (siganl to noise ratio).
So then, 16-bits x 6dB/per bit= 96dB. But that is "IDEAL" and
not real world, especiallly when other aspects are considered.
So in the end your dynamic range will be less and other values
like that 90.3 figure shows up through that Log figure in that 
other email from earlier. That is a more real world value, since
dynamic range is less than signal-to-noise ratio.

Thank you Richard, I was waiting  for someone to mention that.

-Partev



----------------------------------------------------------------------------




--- richarddobson@blueyonder.co.uk wrote:

From: Richard Dobson 
To: csound@lists.bath.ac.uk
Subject: [Csnd] Re: : dynamic range
Date: Sun, 21 Dec 2008 22:30:08 +0000

[coming late to this thread]

I have tended to assume people cite 96dB somewhat casually, based on 1 
bit (doubling of level) = 6dB, so 16bits = 96dB. It is a convenient 
approximation.


With dithering, you can get a dynamic range greater  than 96dB, I forget 
the details. I am rarely in a position to to turn the amp up loud enough 
to notice.

NB: previous to implementing 0dbfs, I wrote the ampdbfs and dbfsamp 
opcodes to enable decibel levels to be written in accordance with 
industry practice (i.e. digital peak = 0dB), even when using the archaic 
  quasi-16bit amplitude model. But as noted elsewhere, setting 0dbfs=1 
is by far the best approach these days.


The logic is very simple - digital peak equates to maximum level 
regardless of sample resolution - if you then define a signal at -110dB 
  you will lose it if rendering to a 16bit file, but retain it (audibly 
or not) if rendering to 24bit or better.  In other words, there is a 
fixed ceiling, but a moveable floor - you can define sounds as quietly 
as you like (e.g. envelope tails), in a predictable way,and  preserve 
them or not (without changing the orch code at all), depending on the 
resolution (file or audio i.o) you render to.


Richard Dobson



Send bugs reports to this list.
To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound"




_____________________________________________________________
Netscape.  Just the Net You Need.