Tap test spectrum Comparison between Standard and Faclate bracing in Tenor Ukuleles

[ebhsbill]

Tap test spectrum Comparison between Standard and Faclate bracing in Tenor Ukuleles.

Over the past 5 weeks I have been experimenting and built 5 Tenor Ukuleles.

I was particularly interested to see what the difference was between common/standard top bracing systems and falcate bracing and different tonewoods. In 2 of these Ukuleles, I used the same materials. The tops were made of Adorondack Spruce, with Sitka Spruce bracing. The first one (2C) used Standard Bracing. The total top mass of the top was 68gms including the bridge and the top thickness was 1.91mm. The second one (5C) used Falcate Bracing. Its top mass was 63gms and the top thickness 2.00mm. Anyway these are the spectrums I came up with when I did a Tap test.

Blue spectrum is for the Standard bracing and the Orange spectrum the Falcate bracing

Anyway, my question are,
"What does this prove?"
"What is good and what is not so good?"
"Are these the sort of results one would expect?"

Any feedback would be greatly appreciated
Bill Biddle

[kiwigeo]

My first thoughts...I wouldn't expect as much difference as that you'd see with a guitar mainly because of the big difference in area of the top. A frequency plot will show you where the important frequency peaks are but it won't accurately show you things like relative volume unless you hit the top with exactly the same amount of force each time. Chladni testing will show up qualitatively how much of the top is vibrating.

[ebhsbill]

Thanks Martin.