Hi,
I'm having a hard time implementing the "switch-and-ramp" technique to cancel out discontinuous control changes as described in Miller's Book at http://crca.ucsd.edu/~msp/techniques/latest/book-html/node63.html
In attached patch I tried to build a very simple example of the technique in action (The Book lacks a Pd example as far as I see), however it only works if the discontinuity is one starting a zero again. Everything else actually amplifies the discontinuity instead of getting rid of it. Does anyone have an idea how to fix that?
Frank Barknecht _ ______footils.org_ __goto10.org__
On 2 May 2007, at 5:35 PM, Frank Barknecht wrote:
it only works if the discontinuity is one starting a zero again
isn't the book describing a way to switch from a playing wave form to
a new one which starts at zero?
The example refers to re-triggering something like a percussion
sample - it is a way to fix the glitch resulting from suddenly
cutting off the 'old' sample (which is likely not at a zero-crossing)
and replacing it by a new one (which starts at zero). The flowchart
shows adding a signal ramping to zero from the last value of the
'old' sample.
That is: the whole example/technique described depends on the
assumption that the re-triggered sample starts from zero, it doesn't
make sense otherwise.
simon
get the attack value at the inconsistency, crossfade back between that value and the original signal.
see attached patch.
of course, the problem is you usually don't know where the inconsistency will arise. the only way around that is to delay the audio while your patch finds such a probem.