[PD] recirculating delay line reverberation time calculation

Claude Heiland-Allen claudiusmaximus at goto10.org
Fri Aug 29 23:07:30 CEST 2008

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,


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