One of my preferred csound option is `-n' (or --nosound).
In my scripts I avoid to write the soundfile adding

#ifdef _NORM_
0dbfs = $_NORM_
#endif

in the csd file and using this shell script

#!/bin/sh
# cs_norm

[ $# -lt 2 ] && echo "Usage: $(basename $0) <norm> <csopt>" && exit 1

NORM="$1"
shift
echo "waiting..."
PEAK=$(csound -d -n -m0 $@ 2>&1 \
    |sed -n '/^end of score.*overall amps:/s/^.*amps://p' \
    |xargs -n1|sort -nr|head -1|xargs echo "(1/$NORM)*"|bc -l)

[ $? -ne 0 ] && PEAK=0
csound -m167 --omacro:_NORM_="$PEAK" $@
exit


For example:

cs_norm 0.5 test.csd
...
end of score.		   overall amps:    -6.02    -6.94
...

tito

On Sun, Feb 05, 2012 at 02:11:14AM -0600, Forrest Cahoon wrote:
> I've found a technique for maximizing csound output level while
> getting no samples out of range that works perfectly every time, and
> since this is a question that has come up more than once on the list,
> I thought I'd share.
> 
> First, in all my instruments, I set my volume as follows:
> 
> iAmp = ampdbfs(p4 + giDBScale)
> 
> This gives me a global variable, giDBScale, which functions as a
> "master volume knob". This is what I will tweak to get the optimal
> overall level.
> 
> While I'm working I keep giDBScale low enough so there are no samples
> out of range; there's no formula for this but since I'm not concerned
> at this point with optimal levels, I've been taking off 10 db at a
> time, so that if -10 db is still giving me samples out of range I'll
> try -20. You won't have to adjust it too often if you use 10 db steps.
> 
> When I'm done and I'm ready to optimize my levels, first I render what
> I have to file. Then I find the volume level with sox like so:
> 
> forrest@supercool:~/csound$ sox test.wav -n stat
> Samples read:           2143042
> Length (seconds):     24.297528
> Scaled by:         2147483647.0
> Maximum amplitude:     0.405457
> Minimum amplitude:    -0.222015
> Midline amplitude:     0.091721
> Mean    norm:          0.049194
> Mean    amplitude:     0.000016
> RMS     amplitude:     0.064597
> Maximum delta:         0.370087
> Minimum delta:         0.000000
> Mean    delta:         0.001209
> RMS     delta:         0.002654
> Rough   frequency:          288
> Volume adjustment:        2.466
> forrest@supercool:~/csound$
> 
> Note that last line, "Volume adjustment". This is how much we need to
> increase the level. We need to convert this to a db value, and add it
> to our current giDBScale value.  The formula is 20 *
> log10(adjustment).  Here's how to do it interactively in python:
> 
> forrest@supercool:~/csound$ python
> Python 2.7.2+ (default, Jan 20 2012, 17:51:10)
> [GCC 4.6.2] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import math
> >>> 20 * math.log10(2.466)
> 7.839861445194257
> >>>
> 
> This is what we need to add to giDBScale. In my current file,
> giDBScale is set to -10. So I usually just use python to compute the
> exact value I need:
> 
> >>> 20 * math.log10(2.466) -10
> -2.1601385548057426
> >>>
> 
> Now this value is very close to exactly what you need to get maximum
> level with no samples out of range. If you use this exact value you'll
> probably get a few (I got 8 just now) and this is probably acceptable.
> I found that I needed to use -2.6 to actually get 0 samples out of
> range, so if you're obsessive like me you probably play with the value
> a bit to get it just right. But you're really super close; it's not a
> shot in the dark.
> 
> I hope some of you on the list find this helpful and/or interesting.
> 
> Forrest
> 
> 
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