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Soundholes and structural integrity (Read 837 times)
konacat
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Soundholes and structural integrity
Sep 8th, 2005 at 3:16pm
 
Although I’m not yet a builder I keep thinking about the process. It would seem to me that a soundhole takes away from the structure of the wood. Of course that is why you have a soundhole patch to reinforce the wood.  Of course the more sound board support structure you add decreases the ability for the top to create it sound. I would think then that a series of small holes would allow for much less bracing and improved sound. The holes, if sized and placed properly, would not effect the structure of the wood and would not need an underling patch.  If this was so then the sound board, being structurally stronger, would need less bracing and therefore have the capacity for better performance. I have seen the side sound ports that people have used and wonder if they were able to use less bracing on the top as a result(if they didn’t add sound holes to the top)?

I was just thinking about it after looking in my Koaloha and its minimal build.  It uses a single bulkhead (like in a ship) that supports the entire top, sides, and back at one time. They also don’t use tentalones for added joint support just the plain joint. Well, it does make it lighter.

Just some thoughts I had.

Mahalo,

Philip
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Ukeman
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Re: Soundholes and structural integrity
Reply #1 - Oct 5th, 2005 at 3:41pm
 
Aloha Philip, Think you have all the right thoughs embedded in your grey matter judging from your post. The whole idea in a nutshell is to get yoiur soundboard to vibrate freely ergo less is good and thinnner is better makes all kine sense. Now couple this basic idea with the fact that string tension adds pull to the uke and especially the soundboard. A set of strings can add 40 to 50 lbs of constant tension...so now we add in another factor....structural integrity...can your thin uke withstand this tension? Are we imploding at the soundhole in front of the bridge, are we having ripples in your soundboard behind the bridge in line with your strings, is the uke deflectin on either sides of the bridge ends, is your bridge lifting and leaning north toward the neck? If so, goodbye intonation and your instrument no longer is tonally accurate....the builder gotta match tension with structure to create an equilibrium...does that make sense? Other variables make it a lifelong chase as wood species are different, stiffnesses and weight change in soundboards are evident even in the same thick nessed and same bookmatched piece. Martin's x brace is a great example of form and function....steeel strings arrived...more tension than gut or nylon, thus the fan changed to the x to balance out the new tension...Ukes with small boxes need less bracing, and your finished uke must pass the test of time.......hope this helps,   laters  ukeman
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