Spreadsheets

[GregHolmberg]

I have posted several spreadsheets here before. Panel thickness, fret positions, fretboard radius/width, neck shape, intonation compensation, 4DOF model, brace stress/sizing.

I decided to combine these into one big spreadsheet file with 20 worksheets, and create connections between them, so when you change one worksheet it affects others. In essence, I've tried to create a complete acoustic guitar model. How accurately this predicts acoustic function is yet to be seen.

I place them here for your use, in the hopes that they will be used to create better acoustic guitars. I feel that the necessity of creating ones own spreadsheets from the book is too high a hurdle for most people, and this has hindered the successful use of the wonderful information in the books. Yes, you can use the books to make a copy of a Medium Falcate steel-string, but I would like to see some new designs.

• Medium steel-string falcate with CF spreadsheet
• Medium steel-string falcate, no CF spreadsheet
• Classical nylon-string falcate with CF spreadsheet
• Wood Properties spreadsheet
• Guitar Modeling Documentation

You may copy and modify these spreadsheets for your own purposes, just always keep the copyright and the links to the original spreadsheet, and to the documentation.

You can work with these directly in Google Sheets (free to use, nothing to install) in your web browser, or can download an Excel or OpenDocument file to work on them offline. Use the File -> Download command in Google Sheets. For the OpenDocument files, I recommend the free LibreOffice software, available on all platforms.

Feedback, constructive or otherwise, is always appreciated.

I'm looking for people who would like to test the spreadsheets and work with me to find bugs. Please send me a PM if you're interested.

Greg

[kiwigeo]

Thanks Greg.....your efforts much appreciated.

[TomBeltran]

I decided to combine these into one big spreadsheet file with 20 worksheets, and create connections between them, so when you change one worksheet it affects others. In essence, I've tried to create a complete acoustic guitar model. How accurately this predicts acoustic function is yet to be seen.

I place them here for your use, in the hopes that they will be used to create better acoustic guitars. I feel that the necessity of creating ones own spreadsheets from the book is too high a hurdle for most people, and this has hindered the successful use of the wonderful information in the books. Yes, you can use the books make a copy of a Medium Falcate steel-string, but I would like to see some new designs.

Greg

Greg - thank you so much for putting these spreadsheets (and your earlier ones) up on the web. I definitively fall in the class of those for whom this would be "too high a hurdle." The thoroughness of you work is incredible. Tom

[joel]

Thanks Greg,

Gratefully nicked!

[edvinguitars.fi]

Thanks Greg

I tested the spreadsheet, made a new nut/saddle and got a big improvement from the values that were written in the Gore book.
I made the optimization for low action using the Libre office solver.

In my case, the problem was I originally made the saddle / nut by the book dimensions but then wanted to make a much lower setup to my guitar. I thought I was weird player preferring as low as 1.5mm/1.8mm action setup, but after quite a few professional Finnish guitar players liked the low action setup, I concluded maybe I'm not alone, it might be a northern preference to play acoustic on so low setup.

With my strings, nut compensation came out only 0.5 .. 1.1 mm, and saddle 0.22-1.06mm

Now, the new setup and compensation scheme is so accurate that I don't trust my tuners any more: some mobile app shows +4c on some fret while some other app show -3c. And my ears hear no difference. I do have a Peterson portable strobe tuner, which I think is the most accurate one I have. But the Peterson does not show how many cents the tuning is off.

Jani

[GregHolmberg]

That's great, Jani. It makes me happy that someone finds it useful.

I'm curious which method you used.

• Measure the action of every fret, every string
• Fit polynomials to the measured data
• Model the neck as a line + ellipse + circle
• Model the neck as a line + parabola

The spreadsheet is set up to do the last three, and by default, it selects the line + parabola method.

This method requires you to go to sheet 'intonation' and set the stiffness of the wood species used for the neck, and it also uses the thickness of the neck from sheet 'neck' and the force of the six strings, all to calculate the deflection of the neck under tension. This deflection is a parabola, according to beam theory.

In any case, glad to hear it worked!

Greg