fft blurring effect
Mar 23, 2012 at 1:06pm
fft blurring effect
how exactly does the “blurring” effect work, wich is part jf charles
well, as i like to build that with ftm i need to understand that.
thanks for any explainations or hintsâ€¦
Mar 23, 2012 at 3:16pm
of course i meant: how does the “blurring” effect work exactly, â€¦
Mar 23, 2012 at 9:45pm
instead of playing each fft frame in the correct order, it randomizes the order in which the frames play according the amount of ‘dither’ you apply (blur width parameter). it is this bit of the patch:
– Pasted Max Patch, click to expand. –
Copy all of the following text.Then, in Max, select New From Clipboard.
There are probably better ways to do it, like treating the spectral representation as an image that you can apply a gaussian blur to (2d convolve) and then play through without the playback jitter…
Mar 23, 2012 at 10:13pm
the good side of stochastic blur from J.F. Charles is that the blur works:
- at audio rate
PS: noise~ in “stochastic blur” patch functions as random generator at audio rate. So each sample, some random number is added to the X (frame) reading position. And also have in mind that sampling rate inside pfft~ is overlap times bigger as in parent patch, therefore noise~ has to be inside pfft~
Mar 24, 2012 at 7:42pm
thanks for help guys,
when i understand you right its about switching between the frames at audiorate.
regarding figure 8 in jfÂ´s paper â€“ one thing is not clear to me.
Mar 24, 2012 at 10:59pm
rather think of switching between bins from neighboring frames. the reading direction is vertical, from bottom to the top, so it’s very similar to asynchronous granular synthesis – instead of reading successive samples (or bins in PV case), you randomly jump forwards and backwards in time in some area around reading position. the width of the area is defined by blur amount (multiplying values generated by noise by some amount)…
so basically your FFT frame is still the same size, as without blur, only the bins for resynthesis are randomly taken from surrounding frames. so the spectrum of blurred frame consists of frequencies and amplitudes from surrounding frames.
Mar 27, 2012 at 6:37pm
i thinks its straight forward. the reading direction is vertical
what you mean with:
what is the realtion between the overlap of the frames and the random distibution?
anyway, everthing nice explained.
You must be logged in to reply to this topic.