Monday, February 27, 2012

Resonance and how to measure it????

Here's what I've been working on's a setup to excite the top of a guitar to test the resonance responses at various frequencies.  The top acts as a speaker when the frequency sweep is fed through a coil, to a rare earth magnet stuck to the top with double sided tape.  The response is then fed to the computer via the microphone and recorded on a chart using a program called "Visual Analyser".  The program captures the responses and, according to my friend Brian Burns, the resulting profile provides you with information regarding the characteristics of the top and ultimately the finished instrument.  Here, I did a profile on Guitar #1 that I completed in '01.  The curve is a bit noisier than those in Brian's example, but the major peaks appear to be near the right location.  Testing of the raw tops is also possible, using a tap method.

I spent more time organizing the shop and trying to get things in very good order so that I know where all of the important tools and materials are.  Wood storage is a problem, but I'll get it the way I want it soon.

It's interesting being located in the Schmoll industrial seems to be full of opportunities for synergy.  Today, I wandered into IndyCraft, a finishing company, which specializes in fine finishes on beautiful wood surfaces.  I talked with owner, Kevin Kinder, who is a musician, martial artist and finishing expert...I'm sure among many other things.  Another business in the park provided me with some Corian material that I used to make the nut on a friends lute.  There's a recording studio, run by an acoustic engineer with whom I've been trying to connect.  I'm sure he could give me some pointers on the acoustic analysis I'm trying to do.  And then there's the coffee roaster the Bier Brewery, the Wine hobbyist shop, etc. etc.  I'm sure that there are resources I haven't even heard about yet.  I did meet the luthier at Paige's music and he might be interested in doing some work together.

Gonna keep on truckin' on the three guitars:  L's, C's and the EI rosewood classical.  Practice WILL make perfect as I go through the various steps of making these instruments.  I may work on and prepare several tops, which may be used on these instruments, depending on their characteristics.  The flamenco will be different from the other two, in that the bracing is much lighter and there are fewer braces.  I think I will employ Brian's design with the transverse braces on the outer edges of the lower bout.  This should provide extra brightness in the trebles for the flamenco sound.

BTW, I'd love to get some feedback from my few subscribers, who've signed on.  I know that my focus right now is guitar making, but for good reason, I have some commitments to keep, to my benefactors as well as myself.  Bear with me.

That's all for now.


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