Am 28.09.2017 um 17:18 schrieb Martin Lind:
To get a realistic (or a musical for matter) sounding reverb it will include
thousands of listening tests with various test signals - I haven't seen any
'automated' or any particular strategy for tuning reverbs in the wild other
than extensive listening tests. The AP delay lines gets longer for each segment
when connected in series, but I don't believe I have seen an overall strategy
for the ratio and it's not particular important to use primes either. It's
obvious that the output taps needs a ping pong behavior.
The reduction to 2 APS in the first post was mainly
to match the RNG structure and for a simplfied example.
I use for instance 2-3 APs in two channels with modulation and a mixing
matrix etc
plus early diffusion stages and / or sparse FIRS outside the loop and
all these things-
But this ratio scheme actually /is /the result of thousands of listening
tests,
some years of reverb building attempts and lots of sneaking into
the reverbs of others...
I found the exactly same ratios +- some cents are used in a nice reverb
from a well known company
that was built for efficiency, whos designer I know and who tweaks them
by ear only AFAIK.
Coincidence? I think not. ;)
You still have to invest time to detune the ratios optimally
and lots of time to design your reverbs, these are just starting points.
But as I said there are strategies for that as well:
For instance you can detune 0.8 by ~ 19 cents to -1/(1-SQRT(5))
which is related to the Golden Ratio and should never repeat,
it's off enough to avoid beating or flanging
but still close enough to 4/5 to increase the echo density immediately...
And this rationale works in all sizes.
Similar numbers exist for diffusion ratios, for instance 0.618... will
give you the flattest response possible and 0.707.. an exponetial decay
of the impulses...
After lots of tweaking I have a reverb that works well for both, rooms
and large spaces,
I also use this as a late stage for a very nice plate reverb for instance,
to me it's become a basic building block now.
And I found that for some lofty reverbs only 2 APs in two channels in a
late stage are sufficient
to sustain the sound if its already decorrelated when it enters the loop,
when you have the right ratios for the AP delay lengths.
/"Don't be afraid if things because they are easy to do"/ - Brian Eno
Of course there must be optimal ratios, cause there are also shitty
ratios that dont work from the start.
And thats why I was curious hwo the RNG approach relates to my current
strategy
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