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About Drums: the physics of overtones

circularscience.com

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Re: About Drums: the physics of overtones

#11

Post by adamnemecek »

dominotw wrote: post #9
adamnemecek wrote: post #2

If you want to learn more about sound design[0], you should check out Syntorial http://www.syntorial.com/#a_aid=AudioKit . It's an interactive software synthesizer that teaches you in like an afternoon more than just about any book or video on the topic. This tutorial series is also illuminating but it's almost too detailed http://sonicbloom.net/en/63-in-depth-synthesis-tutorials-by-... You might also be interested i…

is syntorial worth $129 ? Also I was not clear from the website what kind of synthesis you get to learn. Can you build vst/au with audiokit for integrating with your daw?

It definitely was to me. It's subtractive synthesis with some fm iirc.

Audiokit is audiounit only but yes, yes it does.

Re: About Drums: the physics of overtones

#12

Post by edejong »

algesten wrote: post #3

It's a great article, but the piano tuner in me must correct a detail about "typical musical instruments" such as pianos. The overtones are not necessarily perfect multiples of the base waveform and this is called inharmonicity. In fact, this is part of why a piano sounds like a piano and guitar sounds like a guitar. For any piano and especially the upright, the bass strings are actually too short to produce any vibr…

Any piano can produce the main frequency of the bass notes. Apart from length, the tension and density of the string play a role in the main frequency as well.

The problem with shorter strings is rather simple. Shorter strings are stiffer than their longer equivalents. These strings produce sharp overtones, since there is less length of the string to vibrate on higher frequencies. Perfect overtones need perfect flexibility to be an exact multiple of the main frequency, which is physically impossible.

Re: About Drums: the physics of overtones

#13

Post by edejong »

adamnemecek wrote: post #2

If you want to learn more about sound design[0], you should check out Syntorial http://www.syntorial.com/#a_aid=AudioKit . It's an interactive software synthesizer that teaches you in like an afternoon more than just about any book or video on the topic. This tutorial series is also illuminating but it's almost too detailed http://sonicbloom.net/en/63-in-depth-synthesis-tutorials-by-... You might also be interested i…

Cheaper solution would be to try the open source Pd (PureData) in combination with the free "Programming Electronic Music in Pd" book [1].

[1] http://www.pd-tutorial.com/english/index.html

Re: About Drums: the physics of overtones

#14

Post by wwer »

algesten wrote: post #3

It's a great article, but the piano tuner in me must correct a detail about "typical musical instruments" such as pianos. The overtones are not necessarily perfect multiples of the base waveform and this is called inharmonicity. In fact, this is part of why a piano sounds like a piano and guitar sounds like a guitar. For any piano and especially the upright, the bass strings are actually too short to produce any vibr…

> In fact, this is part of why a piano sounds like a piano and guitar sounds like a guitar.

My understanding is that it is a bit more complex than that, literally!

The the final waveform is a not just

W = sum(a_i * f_i) = Psi

where a_i is the amplitude and f_i are the fundamental frequencies.

It is actually

W = sum(a_i * f_i + sqrt(-1) * (b_i * f_i))

  = Psi + i * Phi
Loosely, the imaginary part plays a significant role in making an instrument sound like it.

Of course, the brain fills up a lot of stuff that is still a mystery but the elec keyboards can set the a_i, b_i to change from "guitar" to "reed organ".

Re: About Drums: the physics of overtones

#16

Post by maheshp »

Well,

Recently I’ve been trying to figure out what is special about mridangam and was wondering if I needed to do some analysis myself. Fortunately, I happened to run into CV Raman’s papers analyzing the physics/acoustics/wave forms of a mridangam that are well worth a read.

He first wrote his short paper in 1920 in Nature (almost 100 years ago) http://dspace.rri.res.in/bitstream/2289/2042/1/1920%20Nature...

his fundamental thesis/analysis is that the way the mridangam is built is special in that produces harmonic tones (integral multiples of frequencies) which is highly unusual for drums therefore giving it the ability to sound uniquely special, accompany vocal well and to be played in a smaller, softer setting.

A good blog delving into all of this including some cool youtube videos at the end on wave spectroscopy demos using talcum powder (related to raman) are at https://croor.wordpress.com/2010/11/10/cv-raman-on-drums/

A longer version of his paper from proceedings of IIS published in 1934 is here: http://dspace.rri.res.in/bitstream/2289/2047/1/1935%20Proc%2...

Figured some of you would be interested in this.

Re: About Drums: the physics of overtones

#17

Post by eon1 »

Applejinx wrote: post #8
eon1 wrote: post #7

Earlier quoted context omitted.

To my understanding it's more like Equal Temperament vs Just Intonation..?

No, those work even with sine waves. What the piano tuner is talking about is timbre: overtones can be not-perfectly-in-tune with the fundamental. Has to do with the thickness of the core windings, I think? Something to do with the string acting partly as a rigid rod, not just an idealized wire. I hear this also in electric bass strings with super-heavy core wires.

Right, you're absolutely correct. I actually "get" inharmonicity, I think lack of sleep and the fact that tuning and the imperfect interval of an octave comes into it (I didn't know that tunings were actually shifted around inharmonicity) made me start thinking about JI/ET.. how embarrassing.

Re: About Drums: the physics of overtones

#18

Post by tel »

edejong wrote: post #13
adamnemecek wrote: post #2

If you want to learn more about sound design[0], you should check out Syntorial http://www.syntorial.com/#a_aid=AudioKit . It's an interactive software synthesizer that teaches you in like an afternoon more than just about any book or video on the topic. This tutorial series is also illuminating but it's almost too detailed http://sonicbloom.net/en/63-in-depth-synthesis-tutorials-by-... You might also be interested i…

Cheaper solution would be to try the open source Pd (PureData) in combination with the free "Programming Electronic Music in Pd" book [1]. [1] http://www.pd-tutorial.com/english/index.html

Or SuperCollider or any demo of a standard synth plugin dropped into a free VST host (like dropping a demo version of Massive [0] into Reaper [1]... though Reaper technically not free).

[0] https://www.native-instruments.com/en/products/komplete/synt... [1] http://www.reaper.fm/

Re: About Drums: the physics of overtones

#19

Post by sn41 »

maheshp wrote: post #16

Well, Recently I’ve been trying to figure out what is special about mridangam and was wondering if I needed to do some analysis myself. Fortunately, I happened to run into CV Raman’s papers analyzing the physics/acoustics/wave forms of a mridangam that are well worth a read. He first wrote his short paper in 1920 in Nature (almost 100 years ago) http://dspace.rri.res.in/bitstream/2289/2042/1/1920%20Nature... his fund…

I have always wanted to understand the result in this paper, since it is one of the first major publications of the first Indian to win a Nobel prize in science. Can you point out to some more basic acoustics?

I've wondered about what similar results hold for Idakka [1], a drum played in Kerala, and the talking drums of Western Africa [2].

[1] https://www.youtube.com/watch?v=kaozNblda54

[2] https://www.youtube.com/watch?v=B4oQJZ2TEVI

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