--- [EMAIL PROTECTED] wrote:
> > Roy said: > > > BUT PLEASE, PLEASE, not in front of the kids. For some reason too > many > > are bored/annoyed when we discuss such fascinating, intriguing > subjects > > as HGs on the HG list. > > > > The heck with that... > Well I'll admit that I was just being nasty because it's one of my few talents, and opportunity knocked... > > Hmm - an "oudman". Took me a moment - oh, a person who works > on/builds ouds! > How cool! How did you find an oudman in Texas, or dare I ask? ;-) You may indeed ask, I found him at work, (DSL tech support). He restores old ouds and has built a few. He built one that sounds like cherry cola with a big stick of cinnamon in it. (He is also interested in fiddles & he plays Levantine (arabic) style.) But as a lute-back is almost identical to an oud-back ... well, mine is simpler... he's the only person within hundreds of miles that knows ANYTHING about it. Additionally he is Turkish but was raised in Palestine, so while I don't understand everyuthing he says, he has such a great accent, it's interesting just to hear him say it. He reminds me a lot of that "former evil genius" guy on Lilo and Stitch. > > No doubt you've found references to relationship between the > soundhole size, > the soundboard thickness, and the body cavity volume. These are all > factors > in the Helmholtz resonance, which states that an air volume of a > particular > size with a port of a particular area and length will resonate at a > particular > frequency. How specific that frequency is is based on the length of > the port > - IIRC the specificity of the frequency drops as the port becomes > shorter. On > a stringed instrument, the port length is the thickness of the > soundboard. > > What all this has to do with HG's is still clouded in mystery, AFAIK. > For > starters, we have the confounding factor of the wheel and braces > effectively > splitting the soundboard into three soundboards. Do we then > calculate the > resonances for the areas under those soundboards? How do we deal > with the > crosstalk between the volumes if we divide them that way? > > Bottom line, Roy, is that I think you should make some soundholes > that look > right to you based on your experience. There are presently no good > models > (well, any models really) for how a HG soundboard and body act as a > unit, so > short of getting your PhD in computational physics to figure it out, > your best > bet may be to let your gut instincts do the work. ;-) Well, I was tempted to let my aesthetic sense do the work. i.e. get a sharpie and draw circles all over it and sand out the ones that don't look good and cut out the ones that do, but as I have another day before I can actually start it (glue, clamp , wait, glue, clamp , wait, repeat ad nausium) I thought I'd ask first. I would like to have two small rosette-filled holes, but the math might be easier with the traditional C-shaped ones, Anyway I thought I should wait and try it without soundholes first - you got that big wheel hole right in front of the bridge, you may not need one. If I can hear the Hayden concertina, (which is not loud enough) it may not be loud enough. But it might be OK for Baroque.... can you play Baroque on an "en Re" instrument? Actually the specific refences were mostly about guitars. How far to to place those Keola Beamer-type holes from the bridge, but I see your point... you might have to figure Volume as well as just distance. Figure the x running around down the soundpost, around the back, up the other soundpost and spreading out over.... That may explain why that 1/4 mahogany HG was such a cannon... more to resonanate. OH BOY..no, I really mean it this time.. where's my sharpie?... But I got the key phrases ... "Helmholtz resonance" and "computational physics". Unfortunately the B.A. completely drained me, so I'll have to settle for Google, instead of the PhD, ... cheaper, may not be as good... Thank you again. Pulled my fat out of the fire, 2 google leads and 3 ideas, which I'll amplify when I've had time to develop them. (Plenty of sanding to do). Roy Trotter
