billkilpatrick
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an oud's moment of truth
over on the lute list there's a very interesting thread concerning the key your oud is made in. here are the initial questions:
- Does a lute maker know how a lute is going to sound as he's building it? Or, is he unsure until he has put tensioned strings on the finished
product?
- I've heard tales of a lutemaker who could tell by knocking on a tree how it will (most likely) sound ...
- I took my lute for repair to a violin maker and she blew in the sound hole to figure out my instrument's tuning: the bowl was in D, she
said.
it's this last entry that really started it off.
what sound does an oud make without strings? (this is not a dharma question...)
- bill
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Elie Riachi
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I think my oud has bias to F note.
I am also told by a PhD physicist and classical violinist that the cavity of a stringed instrument is tuned by the size of the sound hole.
A well known oud maker told me that ouds with three sound holes tend to have a higher pitch sound while the ones with a single sound hole tend to have
deeper tone. This seems to be in agreement with what the PhD physicist further reasoned that by cutting out the two small holes, the soundboard gets
lighter in the region where the smaller holes are.
Regars,
Elie
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billkilpatrick
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bowl note
quite by chance i found a way to gauge the note in which the bowl of your oud is naturally tuned.
stroll into your bathroom (or adjacent duomo) playing the notes of a chromatic scale and listen carefully to the reverberations. the room itself acts
as a sound chamber and any notes played in it resonate sympathetically with "the" note of your instrument's sound chamber. you can get
better reading of this by playing well away from the bridge.
- bill
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Brian Prunka
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Bill,
I believe this method will give you the resonant frequency of the room, not of the bowl of the oud.
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billkilpatrick
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ah....
you may have a point there.
i took two of my charangos into the bathroom to try this experiment (both of which are tuned g - b - e - a' - d' instead of the traditional
tuning). one charango i have is pear-shaped and very similar in sound to a treble lute. it resonated more with "c" while the other,
slightly smaller charango resonated more with "g".
just tried it with my egyptian oud and it wasn't as easy to detect "the" note.
a mandolin maker named gary sent me this:
The usual way in which we measure the Helmholtz resonance is to embed the intrument backside down in a sandbox (with plastic sheeting covering the
sand so as not to scratch the instrument's finish) and place sandbags (plastic sandwich bags filled w/ sand) on the top plate of the instrument.
We then feed the output of a speaker driver via a rubber tube into the body cavity of the instrument. The speaker driver is driven by a signal
generator (sine wave). A microphone is fed into the body cavity and guided into various positions with a stiff wire (a straightened paper clip).
The signal generator output is fed into the x-axis input of an oscilloscope, and the mic output is fed into the y-axis input. The result is a
lissajous figure, a tilted ellipse. We then dial the signal generator frequency up and down until the lissajous figure reaches maximum amplitude.
That frequency is the Helmholtz resonance frequency. As science goes, the above equipment is very cheap. Careful scrounging could get you all of
that gear for under $100. Careful shopping could get you all of that gear new for only a few hundred $.
this site was very helpful as well:
http://www.phys.unsw.edu.au/~jw/Helmholtz.html
if you have a "stranded on a desert island," low-tech solution to this, please let me know.
sincerely - bill
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billkilpatrick
Oud Junkie
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following advice i received from malvrothis, i hummed into the sound-hole of my oud and found that the - e - course responded more readily to
sympathetic vibrations than the other notes.
i therefore conclude that the sound chamber of my oud is naturally tuned to - e -.
mine is an egyptian-made oud. anyone with a turkish-made or other type of oud interested in performing this experiment?
hope to hear from you.
sincerely - bill
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Elie Riachi
Oud Junkie
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Hi Bill,
While this is not a ""stranded on a desert island," low-tech solution ", since you might have to remember to take a chromatic
tunner and batteries with you ' ', but I wonder if one held the oud up
to the mic of a chromatic tuner and tapped the ouds sound board then whatever note the tunner detects would be the oud's natural frequency. Just
a thought...
Regards,
Elie
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billkilpatrick
Oud Junkie
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moment of truth
oddly enough, i thought that over by the solar-powered spa facilites (where my monica bellucci look-alike, personal trainer and her staff of lively
assistants have their suite of rooms) i'd put a socket in the wall of my humidity controlled, air-conditioned, oud-(s) storage unit for a digital
auto tuner.
glad to know we're marching to the same drum.
sincerely - bill
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Elie Riachi
Oud Junkie
Posts: 582
Registered: 4-9-2004
Location: Kansas
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Mood: Gebran Tueni Lives For Ever, 12-12-05.
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| Quote: | Originally posted by billkilpatrick
glad to know we're marching to the same drum.
sincerely - bill |
Speaking of drums, I am in the process of purchasing an Egyptian tabla or a derbakki.
Regards,
Elie
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