<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>>> Wishart describes in his book a technique he calls spectral focusing,<br></div><div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "><div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; ">>> which relies on lpc. He says that lpc can be set to generate a filter<br>>> bank<br>>> which is distributed evenly with respect to pitch, but I’m not sure I<br>>> understand what he means and how it can be done in PD. lpc seems to<br>>> output<br>>> a set of amplitudes for the coefficients. Can I set the filters to<br>>> frequencies of my choice?<br>>><br>Ah...LPC in PD.</div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370"><br></div><div
style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370">I had a go at turning another speech processing system into a PD external with a view to being able to manipulate spectral envelopes and components about 5 years ago, but with no success. What LPC does is split the signal into filter coefficients and excitation - so that the excitation passed through the filter will reconstruct the original signal.</div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370"><br></div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370">There is still no LPC plugin that really works in PD, and my attempt was glitchy and horrible. What would be better would be a pitch+noise separation process, such as is used by Spectral Modelling Synthesis by Xavier Serra at UPF in Barcelona.
It is still available as part of the CLAM package ( <a href="http://clam-project.org/">http://clam-project.org/</a> ).</div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370"><br></div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370">Perhaps the iem_spec library contains some useful FFT related stuff, but to be able to manipulate each frequency component individually is a formidable challenge!</div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370"><br></div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;" class="yui_3_2_0_37_130697101424370">Best,</div><div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"
class="yui_3_2_0_37_130697101424370">Ed</div></div></div></body></html>