� � Thomas, are you recording single isolated drum hits that you analyze? �or are you trying to lift this partial information from a drum track with many hits? if the latter, you'll need to do a transient detection which should be pretty easy with monophonic drum hits. �if the former, then you just need to trim off the silence preceding the onset of the hit. �and the Levine/Smith model is good, but you can probably do it most easily on isolated drum hits even without much reference. then you want a window (or a half-window, like the latter half of a Hann window) to capture the attack transient and window down to zero at the "steady-state". �if there are no snare wires or beads, then i don't think there should be much of a noise component after the initial transient that you window off. �so what is left after the transient should be a collection of decaying sinusoidal partials since it's a drum and not a string or horn, the partials are not likely harmonic. �so then you need to use well-overlapped windowed frames and FFT it. �for analysis, the windows need not be a Hann or Hamming or some complementary window. �for analysis, i would recommend Gaussian windows because each partial will have it's own gaussian bump in the frequency domain and there should be very little sidelobe behavior between partials. �the frequency and amplitude of the partial should be the horizontal location and height of the interpolated peak of each gaussian bump in the frequency domain. �remember the phase for a particular partial of a frame should be the phase of the same partial in the previous frame plus the (angular) frequency times the elapsed time between frames. �that should help confirm tracking of the partial to make sure you're connecting each partial to it's counterpart in the previous frame. �if you're careful, the envelopes should be smooth and mostly monotonically decreasing in amplitude. then synthesize with basic sinusoidal additive synthesis, adding to the windowed attack. good luck. r b-j > > Sinusoidal-only modeling could be limiting for some of the intrinsic > features of percussive sounds. > A possibility would be to encode partials + noise (Serra and Smith, 89) > or partials + noise + transients (Levine and Smith, 98). > > > > On 7/26/2017 4:37 PM, Thomas Rehaag wrote: >> >> can anybody tell me how to track drum partials? Is it even possible? >> What I'd like to have are the frequency & amplitude envelopes of the >> partials so that I can rebuild the drum sounds with additive synthesis. >> >> I've tried it with heavily overlapping FFTs and then building tracks >> from the peaks. >> Feeding the results into the synthesis (~60 generators) brought >> halfway acceptable sounds. Of course after playing with FFT- and >> overlapping step sizes for a while. >> >> But those envelopes were strange and it was very frustrating to see >> the results when I analyzed a synthesized sound containing some simple >> sine sweeps this way. >> Got a good result for the loudest sweep. But the rest was scattered in >> short signals with strange frequencies. >> >> Large FFTs have got the resolution to separate the partials but a bad >> resolution in time so you don't even see the higher partials which are >> gone within a short part of the buffer. >> With small FFTs every bin is crowded with some partials. And every >> kind of mask adds the more artifacts the smaller the FFT is. >> >> Also tried BP filter banks. Even worse! >> It's always resolution in time and frequency fighting each other too >> much for this subject. >> -- � r b-j � � � � � � � � �r...@audioimagination.com � "Imagination is more important than knowledge."
_______________________________________________ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
