# Drum question

Discussion in 'The Projects Forum' started by Vanush, Jan 1, 2011.

1. ### Vanush Thread Starter Active Member

Apr 19, 2008
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Is it possible to 'convert' the sound of a drum to a keyboard instrument, e.g. using signal processing techniques. Measure the pitch of a snare drum, and attempt to recreate it in MATLAB? I don't think it's possible, since a (snare) drum doesn't have a fundamental frequency, does it?

2. ### kubeek AAC Fanatic!

Sep 20, 2005
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I am not really sure what you want to achieve. One way could be triggering, which is a circuit that recognizes the hit and tells a synthetizer to play a note.

As for converting in matlab, you would have to record the sound and work from there, or google how did the old analog synthetizers create drum sounds and recreate that process.

3. ### Vanush Thread Starter Active Member

Apr 19, 2008
46
0
I basically want to be able to play a drum pattern on keyboard, and figure out the notes to play so it will be recognizable from the original and not have it sound like rubbish. The keyboard sound doesn't have to be stock standard piano though.

4. ### Papabravo Expert

Feb 24, 2006
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Like many instruments the sound of a drum is a combination of sounds. There is of course a fundamental frequency along with harmonics generated by the stretched drumhead.

http://paws.kettering.edu/~drussell/Demos/MembraneCircle/Circle.html

The interesting thing about drums is that the harmonics of the various vibrational modes are not integral multiples of the fundamental frequency

5. ### kubeek AAC Fanatic!

Sep 20, 2005
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I think every keyboard has a drum preset, where each key plays some drum sound.

So, what do you really need? Take a song and map it to different drum hits? Like import the song into matlab and get separate key hits as output?

6. ### atferrari AAC Fanatic!

Jan 6, 2004
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Heard it happens with pianos as well, with armonic components not being all exact multiples.

7. ### Vanush Thread Starter Active Member

Apr 19, 2008
46
0
Yes, I know my MIDI keyboard has a drum preset. Even if it sounds like crap, I can replace the samples with higher quality ones. So I would like to be able to play the drum fill on keyboard.
I'm wondering whether measuring the frequency in matlab of each drum hit from the original audio file will help in trying to determine what keys to press (and whne)

Last edited: Jan 2, 2011
8. ### kubeek AAC Fanatic!

Sep 20, 2005
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So, what do you really need? Take a song and map it to different drum hits? Like import the song into matlab and get separate key hits as output?

9. ### bearblock Member

Oct 24, 2008
18
1
i'd describe what you're after as "auto transcription of unpitched percussion". you might want to google that, but you'll need a fair bit of DSP background to make sense of the results.

you could probably just slow down the track in some audio editor and do it by ear.

10. ### Papabravo Expert

Feb 24, 2006
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That's because each key cause multiple stings to be struck and the notes on the separate keys are not related by integral harmonic multiples.

On a single sting however unlike the drumhead the harmonics are integral multiples.

http://paws.kettering.edu/~drussell/Demos/string/Fixed.html