[music-dsp] Costello Reverb...
fintain_d at hotmail.co.uk
Thu Jan 25 11:13:07 EST 2007
I am trying to implement a version of Sean Costellos reverb, but at the
moment it doesn't
sound very good. I'll do a quick walk through of what I am doing,
if there is an obvious mistake please highlight.
Start with 8 circular buffers of 4096 sample.
The operation on each buffer is the same:
A write pointer circles the line. To read a sample, I take the delay time
for a given buffer, as given in the
paper (prime numbers 4127,2143,1933...) and modulation it with low frequency
This is done sampling a noise source at a given frequency,and then linearly
intepolating to this new value over a number of cycles
to smooth the delay time change. Kind of like a smoothed sample and hold.
I then use this post modulation delay time to do a fractional index into the
given circular buffer using linear interpolation.
This is the reverb output for a single delay line.
I then take the write pointer and put in the current audio input sample
along with feedback taken from the buffer at the
pre-modulation with noise point (4127..). Before adding the feedback, it is
first low pass filtered (damping) and subtracted from a scatter
junction coeff, which is based on an average of all the delay lines low pass
Any glaring errors? If need can post some code, but its abit more ugly, even
than this post.
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