billkilpatrick
Oud Junkie
Posts: 563
Registered: 1-3-2004
Location: italy
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Mood: what?
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oval vs round sound hole
is there anything to be gained by having oval shaped sound hole(s) instead of the traditional round shape?
- bill
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AGAPANTHOS
Oud Addict
Posts: 35
Registered: 2-23-2006
Location: CRETE-GREECE
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Mood: hopeful
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Bill
The oval vs sound hole is mainly a stylistic feature and usually implies the origin of the instrument. Ouds with an oval sound hole usually belongs to
the Arabic schlool(s) and ouds with a/or three round sound hole are originated to the Turkish/Ottoman tradition.
My opinion is, as it was already mentioned in the context of this Forum, that the sound hole (s), in general, is an essential technical feature of
string instruments and it has to do with their overall acoustic functioning and performance. It's a part of the breathing system of the
instrument.The Turkish/Ottoman three hole pattern is a much more complicated device and we can compare it to the woofer(the central sound hole) and
the tweeters (the two small ) of the sound speakers of the hi-fi sound system.
I have to mention and stress, by the way, that the position, the size and the openning of the triangle of the three sound holes on the instrument's
soundboard are very decisive questions that we have to test them scientifically on the basis of different assumptions, because we handle it, till now,
through a totaly empirical approach.
That's why the proposal of Master Faruk, to undertake scientific research on oud mechanics and acoustic is a very important and crucial prospect.
AGAPANTHOS
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freya
Oud Junkie
Posts: 275
Registered: 2-8-2004
Location: Asheville NC
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Mood: Happy in the mountains of WNC
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According to this paper that I posted some time ago:
http://www.mikeouds.com/messageboard/viewthread.php?tid=1965#pid122...
There is an interesting mathematical basis relating round to oval sound holes. Basically a oval sound hole (depending on the aspect ratio) has a
smaller effective area than a round hole of equal area. Were these mathematics to hold true in practice, this would be a way of lower the Helmholz
resonance frequency without having to resort to an overly small round hole. It's been too long since I've done serious math to try to calculate the
Helmholtz frequency of Oud bowls based on the math presented in the paper. I take the easy way out and hook my vacuum cleaner up backwards and blow it
across the soundhole - it's really obvious when you get the fundamental going - I measure the frequency with my electronic tuner. When I get around to
it some day I'll record the resonance and look at it's spectrum.
Harry
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