I haven't ever built a CBG with F-holes because I wanted something "edgier" and less "traditional". Who wants their gnarly home-built instrument imitating a violin, right?
But I'm changing my mind, based on this article. Turns out, that shape evolved over hundreds of years of trial and error into the optimal combination of top strength and sound projection. If you want your acoustic CBG to project (a common issue, from what I've seen on CBN and in my own instruments), you should probably be using F-holes.
Check it out.
Why Violins Have F-Holes: The Science & History of a Remarkable Renaissance Design
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There are very practical reasons why the F hole developed in fiddles. The family of instruments need a sound post, connecting the top to the back. To fit it properly you have to put it inside the instrument after the back and belly have been glued up. The F hole allows for the sound post tool to be used to put in the dowel of wood that is the sound post,
Maybe this has something to do with the size of the instrument. Large body acoustic guitars have more volume with a round hole than the F-holes. Then again, most F-hole instruments have arched tops and most round sound holed instruments have flat tops. So it could be related to the shape of the sound chamber which is something the article didn't mention. Then there's the round back Ovation guitars that usually had several round holes of different sizes in the upper bout.
Interesting and confusing at the same time. Try it out and tell us your findings.
So obviously the length of the F-hole is determined by the diameter of the Clementine. That said, would the volume of the instrument be affected by adding a radius to the inner edge of the F-hole allowing a smother flow to the sound waves exiting the body. The shape of the body and curve of the back and soundboard would probably change the volume as well.
I don't think the size of the clementine is important here -- it's the shape of the hole, describing the ratio of a sphere to its surface, that makes it work.
Assuming that to be the case, "ratio of the sphere", then what would happen if you used a grapefruit? Thinking that the size of the fruit needs to be relevant to the size of the box fo it to work properly.
Yep, definitely.
Love it!
From an article in Science News ( www.sciencenews.org/article/how-violin’s-f-holes-influence-its-sound ) I found this as well: "Based on calculations of airflow and experiments, the team found that an instrument with f-shaped holes should have twice the acoustic power of one with circular holes."
I've been interested in f-holes because - unlike violins and guitars - cigar boxes have very strong fundamental resonances. I would think, due to the odd shape of an f-hole that it might lessen the fundamental bump. I'm going to have to make more gits to test that out though. :-)
Yeah, this makes me want to drop my other projects and build a CBG just to test out F-holes.
Hmmm. If I made my own box, I could experiment with different tops, using different F-hole sizes. On the to-do list now.