Official Luthiers Forum!

In the other post below, I solicited ideas for building a test bed guitar for fooling around with ideas. I got quite a few great ideas, and I am really pondering what would need to happen -- to get useful data back out.....

Now.....
The fun part -- What would you test?
Bracing schemes?
Effects of individual braces?
Bridge thickness, weight?
Long ways and cross ways top stiffness?
or just go through some of the available research papers and validate/verify their findings.....
as it seems like several have done FEA analysis -- and then built a guitar and did some simple modifications to that guitar...
but never really validated that the FEA model predictions match except at the 1 or 2 simple test cases.

and then there are the papers that get so close to something important that I would care about.... but then stop short.... like on the Guitar Engineer website -- he did FEA with Brace vs No Brace.... but no FEA for brace vs 20% less stiff brace.... or what happens when you change Tone Bar angles.. or move the peaks around..

Etc?

What would be the response variable in the test?
Frequency response at various frequencies -- which frequencies?
Modal frequency seems to be a popular one... as does Modal Effective Weight (Which I still can't decipher what that means, but I am guessing it means how strong it moves....)

and I kinda need to get my brain around "What does it sound like?"

Thanks

John

In my early days i did a lot of experimentation. I will suggest to keep a building log. Don't make too many changes. One thing I did to help facilitate this was make a dry bolt on guitar so I could pull the top. I didn't do anything fancy just kept things simple. I learned to pull a top easy enough so that I could reuse the same top for some things and reglue it to the same spot.
Most of what I learned from this is that the top is 90% of what you will get out of the box. It is also amazing what a shift of as little as 1/8 of an inch can do.
have fun
john hall
blues creek guitars

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it