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Wow, this stuff is fun, I wish I had time for more of it.
Kevin, where did you tap or bonk the guitar when it was finished? Is it just one bonk or many, averaged.
When I do this kind of thing I usually push that button export and a string of numbers can be captured and put into Excel. You can cut out a lot of the low and high and just get the frequencies you want. Then you can plot the changes with different color lines on an x-y graph.

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Ken

I bonk it on the bridge. I made a mallet with a super ball & a dowel rod.

I do several bonks, maybe 20.

Then I look at the waves to find 3 successive ones that look very consistent and analyze them.

I've been saving all of my tap tests so I can plot them together. For now I just look at the plots that Audacity draws.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Interesting. How do you know that those 3 are the "right" ones? Obviously you would want to throw out any double taps and what not, but what other criteria do you use?

I would think that by picking and choosing the ones you like, you are defeating the purpose of averaging multiple taps. There is some inherent variability in the tap testing process, but that's why you would average multiple taps that look different, because you don't know which ones are "correct".

I do around 8 to 10 taps about 1 second apart and select them all before plotting the spectrum in Audacity, this gives a good average of what was happening during the taps. As for what you are seeing there is lots of info on this forum and other internet sites.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I hadn't thought about a tap being wrong or right. The only reason I grabbed multiple taps is because a single tap does not provide enough data for analysis. I was grabbing 3 consecutive taps that all had good amplitude (not down in the weeds and not clipping) and all looked similar, assuming repeatability indicated accuracy. Since I record about 15 to 20 taps, I've gone back & analyzed the whole chain & the peaks still fall on the same frequencies.

Now back to trying to shift those frequencies.


Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.