Hi, i added an experimental feature to libconvolve/jack_convolve which might be able to preserve some of those precious cpu cycles from being burnt. jack_convolve now has commandline switches --min_bin=bin_no and --max_bin=bin_no which can be used to specify which bins of the fourier transformed signal and response to multiply. The range for both is always 0..periodsize+1, but min_bin must always be < than max_bin.. An example: assuming jack periodsize of 2048 and samplerate of 48khz: jack_convolve response_file.wav --max_bin=1200 This leaves out the top 849 bins out of the multiplication and thus reduces cpu load by ca. 2/5. The cost is that the high frequency spectrum is cut off. And it's not even a really clean cutoff which jack_convolve response_file.wav --max_bin=40 would show (you get crackles due to edge effects, etc). This feature is probably most useful to get some preview with degraded quality but less cpu consumption. Although at some samplerates it even makes sense. Assume a samplerate of 96khz, then there's quite a bit of signal which doesn't need to be processed since it's far out of the range of human perception. the min_bin parameter is not really useful and only included for completeness sake :) It cuts out low frequency bins out of the equation. Due to the crackle effects when throwing away bins that are audible one should not use these settings for filtering of the convolution in the audible frequency range.. In one of the previous releases (which went unannounced i think) i also added a gain argument which can be used to boost the level of the convolution output. Example: jack_convolve response_file.wav --gain=4.0 to get a 300% increase in level.. Regards, Flo P.S.: I am also currently working on a qt app which uses libconvolve, but it might still take a while until initial release (due to my time constraints induced by studying). Preliminary screenshot here: http://www.affenbande.org/~tapas/wordpress/?page_id=27 Help would, of course, be appreciated :) Anyone know of waveform or vu meter widgets for qt which are reusable? Flo -- Palimm Palimm! http://affenbande.org/~tapas/