Except that he is using fixed frequency oscillators, which are
amplitude modulated by the data. fiddle~ is for frwequency tracking,
which is not relelvant here. He suggests using fft; you might also
try narrow band filters tuned to each of the frequencies.
Lawrence Casserley - firstname.lastname@example.org
Lawrence Electronic Operations - www.lcasserley.co.uk
Colourscape Music Festivals - www.colourscape.org.uk
Here is a patch that theoretically does something like what you will
need to do. The rect~ objects are merely there as a model of the square
waves that you will be receiving from your audio interface. The FFT
portion passes only a specific frequency bin of amplitude data. From
this, you can use abs~ and rampsmooth~ to follow the amplitude of the
signal. Remember that you will most likely need to tune your
oscillators so that they fit nicely into different frequency bins.
Looking at the schematic, it appears that the left and right channel use
the same oscillators.
Seems like a pretty cool circuit. I may try building it myself just to
see if it works as advertised.