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View Full Version : Dana Bourgeois Articles on Tone, Tapping, Wood, and more



Matt Clara
12-03-2009, 02:53 AM
I see one of these articles has been referenced at least twice here at the Luthier's Lounge, but it was in the middle of another thread, as a reference or response to a side issue. I stumbled on them recently while researching tap tuning and found them all interesting and informative, and thought I'd share them with the group directly.

http://www.pantheonguitars.com/DanaBourgeois_articles.htm

I should add, Dana is a guitar builder, and not a uke builder.

thistle3585
12-03-2009, 04:35 AM
I am nowhere near being an expert in this area, but when I first started building instruments I thought a short cut to determining top and back thickness could be found via deflection tuning or tap tuning to a certain note. I found that not to be the case but settled on carving away until the top "rang clearly' when tapped. I think a good exercise in understanding this is to leave braces heavy on a top then start thinning them and tapping to hear the difference as they are thinned. You'll notice how a thud turns into a bell like ring as you go thinner then it will turn back to a thud. I am always fascinated by how more accomplished builders achieve their thicknesses and hop Chuck or Pete will chime in. For further study, look up Chladni plate tuning or free plate tuning. There are also some good videos of the process on youtube.

Moore Bettah Ukuleles
12-03-2009, 06:25 AM
For me, tap tuning a ukulele soundboard is more difficult that with a guitar sound board, because of it's small size. I'm not saying it can't be done, I just never got the hang of it. I will sand the top plate until I get a nice ring to it when tapped and then stop. Going too far and too thin and that bell-like quality will get thin. Choosing the right wood to begin with is very important. Drop a board on it's end a couple of inches above a concrete floor and you'll be able to determine whether or not it'll make a good instrument. That's one of the factors of how I'll choose wood at the mill. I rely heavily on top deflection which is something learned through experience and intuition. No matter what the boards sounds like, it's going to be dead if it doesn't move. I met with David Hurd the other day and he showed me his scientific approach to measuring top deflection. It's a method of mapping the top in order to get repeatable results.

uluapoundr
12-03-2009, 11:09 AM
I've always found this topic fascinating. When I pick up a new uke to play, I give the top some taps to see how it responds. If you've heard an uke that sounds good, you know what sound you are looking for. David Hurd's ukes (Ukuleles By Kawika) have great sound and is a testament to his scientific approach. Chuck's ukes also have that sound and I'm guessing there's less science and more of an artisan's approach. Koa seems to be a very diverse wood, which is possibly why some ukes from the same builder/company have varying results.

Moore Bettah Ukuleles
12-03-2009, 11:55 AM
From the things I've read and heard, koa is very difficult to tap tune, at least when compared to the spruces. My tuning consists of thumping around on the glued on top, looking for a ringing note, usually a G# on a tenor, while checking that the top deflects where I want it to. I believe it's better to have thinner braces than a top that is too thin.

Oh, and HAPPY BIRTHDAY Ulaupoundr!!!!!!

uluapoundr
12-03-2009, 08:04 PM
From the things I've read and heard, koa is very difficult to tap tune, at least when compared to the spruces. My tuning consists of thumping around on the glued on top, looking for a ringing note, usually a G# on a tenor, while checking that the top deflects where I want it to. I believe it's better to have thinner braces than a top that is too thin.

Oh, and HAPPY BIRTHDAY Ulaupoundr!!!!!!

Thanks Chuck!

I've always wondered what the right combination was with bracing, top, and finish thickness. You hear so much about thin to no finish for optimum sound. I think it was you Chuck who shared that finish can be used to actually enhance an instrument's sound.

Matt Clara
12-04-2009, 01:14 AM
My intent was to share the articles, nothing more.
They really are good articles, whether you tap tune or not.
Chuck's method does sound the most straight forward, though it does sound like there is some nuance only lots of experience could afford.