[PD] recirculating delay line reverberation time calculation

Miller Puckette mpuckett at imusic1.ucsd.edu
Mon Sep 1 10:44:42 CEST 2008

hi all,

I don't think anyone knows the answer to this.  Traditionally, ever since
Schroeder's reverberator, I think people have used delay times within a ratio
of 1.5:1 of each other so that any old mean works OK.


On Fri, Aug 29, 2008 at 10:07:30PM +0100, Claude Heiland-Allen wrote:
> Hi all,
> Referring to Miller's book [1], and having experimented with various 
> delay times,  I'm wondering what the "average" delay time used in the 
> text is.  If all the delay times are close to equal, then using the 
> arithmetic mean as "average" gives me a reasonably accurate 
> reverberation time calculation.  But the more they differ the worse the 
> result is (comparing with measurement against my implementation).
> [1] http://crca.ucsd.edu/~msp/techniques/latest/book-html/node111.html
> Intuitively it seems that the sound recirculates more often (and is thus 
> attenuated more) through the shorter delay lines, but this is obviously 
> not taken into account with arithmetic mean.  I'm thinking something 
> like harmonic mean might be better (but I tried it and it wasn't a huge 
> improvement, nor was geometric mean).
> Any clarification would be enlightening, thanks,
> Claude
> -- 
> http://claudiusmaximus.goto10.org
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