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Thanks again Arie for the valuable info and there you go again with terms I have no understanding of . I'm off to Google cross dipole. Whew.

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If you want to hear the difference of tap tones as a top is worked get the John Mayes voicing video it gives a good audio of what we need to hear. His advance voicing video covers several different tops with different woods.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

arie,

Just curious, but how would anyone get the tap tone the same all over the soundboard?......or even the same all over the lower bout? Seems it will always tap better when tapped on the active area of a mode and since the monopole mode is the biggest sound producer tapping on or around the bridge plate really sets it off. So how could one even get close to that tap tone when tapping near the perimeter or to the side of the soundhole?

I'm guessing I'm misunderstanding what you are trying to say.....thus the question.

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Formerly known as Adaboy.......

Thanks Fred,

Yeah I should really make the effort to get those videos. Some day.

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I don't see any flaws in your argument and I wish I could help understand things any better. I'm busy tapping away anyway just so I can find a place in my brain to store some pieces of info for future reference.

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Thank You and Best To All

That guitar has a nice mid range punch. If that is what you are going for then you might get there with that bracing but like others said I think it's a bit heavy by the looks of it. FWIW I don't build with bass/treble 'sides' of the top in mind. As was mentioned before this could just jut make one side weak and the other over braced. A common solution to this problem is to brace symmetrically, or close to it and thin the bracing as well as the top out to the perimeters of the lower bout. So in essence if you still want to thing of the top as being separated into stiff treble sides and thin bass sides then what you would have is a stiff center around the bridge and a thin edge on the perimeter.

But who knows? If you glue up that box as is (with a little more off that one X-brace) you could have a nice guitar.

i usually just hold the free plate between my thumb and index finger right in the area where the fretboard extension would be and tap away. don't even look at the thing just listen and you'll hear differences in pitch all over. i'll shave down the tops of the braces to kinda rough them in, then for fine tuning i'll just sand the sides of the braces with a block of wood with some psa on it. first braces to go on are the x braces and i'll work them until for lack of a better word, their presence on the plate is transparent. any areas that have a higher pitch get worked. next up are the tone bar/bars -same deal. then finger braces, utg, and sound hole re-enforcement. bridge plate is last and i'll listen for what change if any happens when it's glued down. if there is, then i'll work the braces again. i use parabolic, tapered braces and that may or may not have something to do with it. somogyi goes into this in one of his books which is where i got it from and for me it seems to make sense for the way i am currently building. i don't use any electronics or anything just my ears.

iirc ancient classical builders would add clay "lumps" to the top in areas where they would want to increase the pitch then replace these lumps with small wooden patches in an attempt to even out the tone.

If you go back through the brief stuff Trevor wrote on the post.... There's a few bits that if you search around - you will find more in depth explanation...

One critical bit is asymmetry.. of WHAT?... Asymmetrical bracing doesn't always yield asymmetrical vibrational nodes.... and in fact - asymmetrical bracing can be used to even out the nodes on plates with significant runout or differences in stiffness... This might have been where the "Bass half" and "Treble half" myths started out - when Luthiers back in the day may not have had as much control over the timber they received... so they had to make wood with lots of runout work...

If you really, truly want to experiment with "Asymmetrical" nodes - you can take a reasonable swing at this by using several closely spaced, parallel tone bars that are parallel to one of the X-legs... like say switch from your fan to 2 parallel tone bars about 1" apart... and have the first one start butted up to the bridge plate... Don't scallop or taper them.

With your current iteration... I would vote for try it out and see what happens. Just make sure that you have plenty of bridge overlapping your X-legs...

Thanks