Official Luthiers Forum!

If I want to bring the overall pitch of the guitar up a bit, make it a little brighter, I would make the sound hole larger. I can do this to an existing guitar. What's the incremental scale? If you enlarge the hole by 1/16" on a 4" hole does it change it dramatically? Just enough to hear a difference? Anyone experimeted with this? Clinton

Hi Clinton;
I can offer that I have tried it the other way on a yamaha dread. I "filled" the sound hole in to hear a change, and had to close it up by 1/4" to hear any dicernible difference in tone change. Even at that it was very minute.
In theory I guess you could take it the other way, as I doubt 1/16" would make much of a difference at all. Some may argue differently, and I'm sure there is s formula for this, but several factors would play a part in this adjustment for treble gain, box size/volume, string gauge/tension. scale length, top thickness, finish, etc..I guess if you have a guinea pig start small and try it in increments until you're satisfied with the sound.

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Nehemiah Covey
www.coveysacoustics.com

It's often hard to enlarge an existing sound hole enough to make much difference. This is one of those places where putting in a 'port' can make the guitar sound better, as it will raise rhe 'main air' pitch. Try a fairly small (say 1" diameter) hole in the wide part of the upper bout, and see what that does. One of my students did that on a reso he made, and just kept enlarging the port with a Dremel until the sound started getting worse. THen he made nice looking surround that closed the hole up a little.

I've come to the assumption that when I read a dimension for the soundhole for 3 13/16 that if it ends up at 4 inches it will not alter the sound to much extent. I think I'm going to have to research and experiment with sound ports. Clinton