Official Luthiers Forum!

In lots of places I've come across statements to the effect that the upper bout of a steel string guitar is a "tonally inert area". The more I build the more I think that this is just plain wrong.

It never ceases to amaze me hearing the change in tap tone of a top in the lower bout area (and particularly when you tap the bridge plate)when the upper transverse brace is glued in. The top just comes alive. I've just done this on my latest - my take on a Grand Concert - and have come back from the workshop with a big smile on my face to share this with you OLF'ers.

This time I also took the trouble to hold the top by the lower bout edges and tap the upper bout area before the transverse brace was glued in. There is lots of stuff tonally going on up there. I think that to brace the upper bout area for structural reasons alone rather than tonal considerations is missing a big trick.

Interestingly I don't think putting in a cutaway has much of affect on the sound.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Hi Dave, i must admit that i'm no expert on this but when i built my first one, i had the same feeling than what you described. Idon't know much but do have a feeling that the reinforced upper bout plays it's role in the transmission of tone

I think the upper bout doesn't produce a lot of sound in a guitar but that's not to say that the area doesn't have an effect on the tone of the the guitar. You are adding mass to the top so surely you will notice a change in the tap tone, especially in the free plate.

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Tickle your guitar daily, and it'll tickle you back.

I agree with JH that there is not much sound produced by the upper bout of the top, given the dampening of the fretboard and transverse brace. However, the upper bout of the back can reinforce the mid range (if it's not overbraced)acting like a small, sympathetic resonating drum head. Of course, in classical guitars, the neck foot kills most of that.

However, the cross sectional shape of the arms of the X has a major effect on harmonics. Tapping the top over the arms can either produce a ringing, sustained tone, or a dead one. There is also an interaction between each arm and with the legs of the X that I am still exploring.   

Stay tuned,

Scott

[QUOTE=Scott van Linge] I agree with JH that there is not much sound produced by the upper bout of the top, given the dampening of the fretboard and transverse brace. [/QUOTE]

Hi Scott,

But if you have a free-floating fingerboard as part of a neck extension, and the neck block supported by carbon fibre flying buttress braces, then you don't need the upper top bracing to be "structural". Hence you take away a lot of the bracing and have a much lighter transverse brace. That's my point really, if you are bracing for structure, sure you "kill" the upper bout of the top's ability to produce sound, but if you are bracing for "tone" then it is there (at least imho).

Rick Turner is a pioneer of this sort of design (and I think Howard Klepper is too), and Rick has reported in a recent AG post:

"I feel that freeing the top to vibrate adds to the complexity and sustain of the upper partials. The harmonic sustain on the acoustics I've built is very, very nice."
Dave White38740.4052546296

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Pics of the Free Floating Fretboard?

Bruce,

I posted these pics of a guitar bouzouki with this in this thread recently:





Plus here's one of the flying buttress braces:

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I agree, and I have been wondering myself why guitars don't have floating fretboards. I'm hoping somebody chimes in as to why this would be a bad idea before I build myself a disaster someday.

Get back in the square Dave .....anything could happen out there. Seriously, very innovative stuff Dave but you have a flair for innovation.

Have ordered my second lazy sue

Cheers

Kim

Kim,

Thank you for your kind words but I'm not really that innovative as few of these ideas are original or mine. I just have a "magpie" tendency for picking up things I find "interesting" and then putting them all together. Forums like this and the open nauture of nearly all guitar makers make it a lot easier.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Dave I could not agree more, this forum and others like it are an absolute gift especially for those of us trying to make a start.

Cheers

Kim

Dave that is so majorly cool. What are you talking about? This guitar doesn't even have an upper bout? Doesn't it join the body at the sixteenth fret? I'm really interested in hearing this one.

Why don't you do a world tour with it, letting each OLFer pay the freight on to the next person, kind of like Tim McKnight did with at least one of his.

Cool guitar, and yes, if you structurally support everthing off that upper region, it should begin to have some good vibes up there. It's cheating if you asked me! Great design.

A lot of us prefer to use tail wedge instead of butt wedge. In the case of your flying buttresses, one might call them flying neck braces.....

Bruce,

Yup - it joins at the 16th fret. Again not my original idea but borrowed from the "master" Stefan Sobell. It gives you great upper fret access from both sides of the fret board which, trust me, is a good thing on a bouzouki. I am also using the same neck principle on 14 fret join guitars as well. I'll post some detailed pics of the current one when I finish it.

I'd happily send one on a "grand tour" if y'all will stump up the shipping and customs etc charges. Even better if you pay my "shipping" I'll come and play it for you all

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Where is the signup? We'll have to divide the cost to get it over here among the signees. Insurance of course. You might even sell one during it's travels. Woolson did. I shipped a Reverse headstock Firebird to Norway, cost about $100US.