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This is the second posting for this question, but I wasn't paying attention and posted it in the electric guitar forum the first time. There is not much use for them there.

I am planing my first sound port and was wondering just how large or small to make it for optimal effect. I have been thinking about this for a while and have read everything that I have seen posted but don't recall seeing this detail discussed. I think I recall that a sound port changes the main air resonance and can be compensated for by adjusting the size of the sound hole. But I am at a loss as to how much on this is necessary.

Feel free to correct any of these statements if I am off base. I am needing to learn and being wrong is nothing new for me.

Cecil

What I've done on previous soundports is take the area of the desired soundport and subtract that from the area of the soundhole so that it doesn't change the frequency too much. If I have a soundport that is approximately 1.5 square inches then I subtract that from the 12.56 square inches from my original soundhole size of 4" diam. and my new size becomes 3.71" diam. I'm not sure if that helps at all, but good luck. I've really enjoyed the guitars that I've put soundports in.

From what side ports I've seen people incorporate, I am concluding most don't compensate the soundhole size for the size of the sideport. I'm not saying that area compensation isn't a possible necessity...it just seems like I see a plethora of sizes shapes and locations that don't correlate to the size of the soundhole...or some guitars wouldn't have a soundhole at all.

I've done 2 L-OO's recently, one with a side port in the upper bout and the other without and it doesn't seem to make any difference on front projection. The port does give you the option to hear yourself playing a little bit better. At 60---I need all the help hearing I can......but also don't like to listen to my aging playing either.

I'm not analytical enough to come up with a guitar port formula for you....and why.

Kent

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EXCELLENCE IN SCULPTURE, CARVING, LUTHIER, ARCHITECTURAL MILLWORK AND DESIGN

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From the reading I've done, anything from about 1" diameter round works. Some get
very large- ovals 2" x3" or so. I've only done the small ones, and I really like the change
in the player's experience. I may try a larger one someday, but I would start to worry about
the overall effect on the main air resonance. At some point the effect of the soundhole
is going to change that resonance significantly.

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

I like those side ports with the sliding cover. So you can have it opened or closed.

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Jason Moe
LaCrosse WI 54601