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Have any of you experimented with the affects of soundhole placement?

The reason I ask is on my auditorium guitars the center of my soundhole is
5-7/8" from the neck-edge of the body.
I finished my rosette this morning and flipped the top over to find that
somehow I managed to be about 3/8" lower than my drawn out bracing
pattern, for a total of 6-1/4" to center.
I couldn't see where it warranted scraping the top and chose to nudge the
upper transverse brace down about an 1/8" from it's original location and
chose to proceed with the build.

Man, I had my sights set on being mistake free this time too!

_________________
Christopher C. Cordle
North Muskegon, MI

http://www.yardsaleunderwear.com
http://www.facebook.com/christopher.cordle

Chris-
This might give you a chance to add another fret to the fingerboard length.
"It's not a mistake, just a chance to make something unique!"

Cheers
John

I take it the profile is already cut out Chris?

If not, just move the layout down 3/8".

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Even still, if the profile is cut out, can't you move it down a bit. I don't know to many builders who cut the profile out to the exact size, most leave 1/2" or so.

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My Facebook Guitar Page

"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Get the first 'Big Red Book' from the GAL, and look up William Allen's article 'The Basics of Air Resonance'. He made measurements of air modes on different boxes with holes in different places, and made sense of it all in a very useful way.

Moving the soundhole down toward the middle of the box will raise the pitch of the 'main air' resonance somewhat. This is the lowest pitched resonance that can actually put out sound effectively, and has a lot to do with how the lowest notes sound. If my experience is any guide, the move you've made will have a noticable 'brightening' effect on the low range. There are a couple of things you might be able to do to recover.

If you haven't already cut the hole out, make it a bit smaller than usual. This will leaver a wide margin on the rosette, but that's not so bad. It's also easy enough to enlarge the hole later if you want.

You might try making the body a shade deeper; even an extra 1/4"-3/8" can make a difference. This doesn't so much drop the final air mode pitch as it does 'smooth out' and broaden the resonance, spreasding it over a bit wider pitch band. This makes the bass tone a bit 'darker' to a lot of folks.

The easiest way to get a 'bassier' responce is often to 'tune' the main back resonance to something like a semitone higher than the 'main top' tap tone pitch once the guitar is assembled. On most guitars you end up shaving braces to do this. The nice thing about it is tha it brings up the bass without altering the treble at all, as thinning the top or scalloping the top braces will. It's also structurally less ofa problem.      

Thanks Alan & Rod,

Yes, the top was already cut out. I had about an 1/8" I was able to recover
which puts me right around 1/4" lower than originally planned for.

The article sounds fascinating...I'm sure there's many scientific
approaches to doing this art and I'll keep learning along the way.
The man I learned guitar building from always told me "you can get as
scientific as you care too, and I don't care to".
For me, I think once I feel I've become one with the basic principles of the
art, I will look to expand my knowledge into the nuances.

I'm anxious to hear how this one sounds. I closed the box last night and it
has a good thump to the box. I'm thinking it's going to be just fine.

_________________
Christopher C. Cordle
North Muskegon, MI

http://www.yardsaleunderwear.com
http://www.facebook.com/christopher.cordle