Re: [Bluemusic-users] Modal Freqs
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From: Mark V. P. <Mar...@te...> - 2007-10-07 10:56:11
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I downloaded Praat this week and experimented with it. I rendered a single note of a xylophone with a soundfont (Campbells_Grand_Xylophone) to a wavefile and loaded it in Praat. It looks like this one needs at most 8 formants, because when I tried more formants, several formants had about the same values. The textfile produced by Praat contains a frequency and a bandwidth for each formant. The mode opcode requires a frequency and a quality, but you can convert this easily with the formula quality = frequency / bandwidth. I didn't average the values, because the values seem quite constant. When I made an instrument with the 8 formants, it sounded like a xylophone but still not like the original sample. idur = p3 iamp = ampdb(p4) aexc mpulse 1, 0 a1 mode aexc, 1582.29932, 1582.29932/7.89720488 a2 mode aexc, 2225.94, 2225.94/10.8666286 a3 mode aexc, 2746.1, 2746.1/2.10496593 a4 mode aexc, 3595.45, 3595.45/22.9179974 a5 mode aexc, 4504.3584 , 4504.3584 /27.6062775 a6 mode aexc, 5079.95215 , 5079.95215 / 18.8226795 a7 mode aexc, 182.29932, 182.29932/302.28 a8 mode aexc, 1606.29932, 1606.29932/391.61 asig = (a1+a2+a3+a4+a5+a6+a7+a8)*iamp ;asig = (a8)*iamp blueMixerOut asig, asig a7 and a8 can be removed without affecting the sound. I tried using the bandwidth value instead of the quality, which ironically made it sound a little better, but still not like the original (in this case you can remove all of them except a7 and a8 ). The most likely problem is that Praat doesn't give amplitudes for the formants. I therefore used the same amplitude for all of them, but this means that a formant may be too strong or too weak. Praat is actually meant to *recognize* a sound (what is needed in speech recognition), not too *imitate* a sound (which is what we want). -- Mark _________________________________________ When you get lemons, you make lemonade. When you get hardware, you make software. |