Establishing the target plate thickness for Flamenco guitars

[josswinn]

I have spent all day in Excel and section 4.5.2 of the Design book. I think I have achieved what I set out to do, but would appreciate it if someone could check my numbers and spreadsheet formulas.

You can see all the numbers in the spreadsheet and click on the cells for the formulas here:
https://docs.google.com/spreadsheets/d/ ... sp=sharing

I have measured a piece of Cedar of Lebanon, which I plan to use for the back and sides of my next Flamenco guitar.

What it seems to be telling me is that a classical back with Trevor's suggested vibrational stiffness value of 50 should be 2.26mm thick. Right? However, since this is a flamenco, I think that the vibrational stiffness value should be lower than a classical.

By the way, the average back thickness of 19 flamenco blanca guitars in the Sheldon Urlick collection is 1.95mm:
https://docs.google.com/spreadsheets/d/ ... sp=sharing

Thanks for any help checking the spreadsheet formulas. It's been over 30 years since I had to study equations...

[johnparchem]

I had a very good Flamenco guitar in my shop with the back having a lower resonance than the top; a very thin back. I used Spanish cypress and use the same back vibrational stiffness that I use for classicals and pitched the back for semitones from the top. That might not be typical for a flamenco. Although my top vibration was 5 less than Trevor's suggested value in the book for classical.