And for people with a lot of time on their hands, we added the Sliding DFT version (analysis frame updated every sample) a few years ago - including a simple instance of frequency domain convolution for the windowing. A real-time version of this was presented at ICMC last year, running on a GPU.
Hm, I have "some" time on my hands but would rather exchange it for some money, but I'm interested in the graphics card acceleration (I know I have a library for NVidia's Cuda 4.1 which should plug right in the Jamin FFT I compiled with fftw3), is this implementations somewhat Open Source, or not? Also, did it give good speedup ?
Oh, and about the whole idea, apart from the main considerations and of course the studio path experiment, there is also a main point concerning sub-sample information in the sense of perfect reconstruction in the well known sense of being able to reconstruct the original signal from the samples. This for instance is important when you put the signal with (partial) FFT transform based processing lets say running at a 44.1 kHz sample rate on a DA converter with it's built in reconstruction/oversampling/anti-aliasing filter.
It is highly unlikely that once especially the higher frequencies pass though some sort of short term convolution/averaging filtering made by a FFT the "linear" properties and filter-alikeness with analog filters are such that the reconstruction-ability (and therewith also the re-sample-ability in propwer sinc-sense) us still intact. In short: please keep the FFt effects in at least the low range (because of those horrible "always the same" near-DC transform products) and the high range (because of those sampling issues) away from my CDs and Blurays! I like to play back the materials over a 192 kS/s 24 bit DA converter with excellent distortion figures and the conversion to 192 works great on neutrally digitized signals and decent DSP processing (analog-congruent filter in the sense of z-1 for "s" or such things are reasonable for not-to-high frequencies), but many materials have been messed with, which I deplore.
So it wouldn't be a bad idea to check with the better studio people (I mean the great ones, of course) to get a piece of their mind about how to create digital effect equipment which can bring back the *music* and wonderful sounds, and what are right ways to go about using the great new processign resources we have at our disposal!
Theo. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
