Thread: Acoustic Soundboard

The subject of sound board tone has fasinated me ever since a violin maker explained to me that all violin soundboards are tuned to produce a "D" when tapped, I don't think he was bull s***ing me.

Is there a similar specification for an acoustic guitar?

Different,

3 seconds sounds good to me. The length of the ring is one variable, others are the spread of the note (ie how many harmonics are produced) and the note itself. Im not sure that more is always better but there are makers who have very well specified notes for each component of their instruments.

As for the number of pieces, I cant see any reason why three or more pieces cant be used. Of course they need to be properly joined but structurally or acoustically there is no reason I know of..... I have an interesting piece of WRC with tight quartersawn grain that I want to put a piece of Monterey Cypress in the middle of. There will be issues of differential expansion whan humidity changes but its on my "why not?" list.


Billie,

I dont know if its a D (Mathew do you know?) but I do know that there are tight tap tone specifications and these form part of the intellectual property of violin makers. This applies for the box, soundpost placement etc as well.

I think the precise specifications for guitars are also the territory of intellectual property for a lot of makers. I dont know if the big factories do it anymore but boutique makers almost always do. A lot of the hype surrounding Lloyd Loar's instruments made for the Gibson company is the fact that each component was tap tuned to produce an overall sound profile. Google his name and you will find out more than you want to know. I do know they dropped the practise as production volumes increased. A lot of manufacturers use a gauge to measure the stiffness of the soundboard which produces similar results. But dont expect such an instrument for $500........

Two pieces are common because resawing a billet into book matched halves is the most economical way to yield maximum amount of useable quarter sawn wood from a tree.

Originally Posted by kiwigeo

Two pieces are common because resawing a billet into book matched halves is the most economical way to yield maximum amount of useable quarter sawn wood from a tree.

True but if the board you are going to resaw is only 150mm wide you have to use 3 pieces or make a tiny guitar!


Ross

Yes of course. If the billet is smaller than what is usually milled for tops and backs then a three piece back is quite a sensible way to go. Torres and other famous luthiers often made three or four piece backs and at times even tops.

Ive even seen a guitar with a top made with each half a different tonewood.

Cheers Martin

Originally Posted by kiwigeo

Yes of course. If the billet is smaller than what is usually milled for tops and backs then a three piece back is quite a sensible way to go. Torres and other famous luthiers often made three or four piece backs and at times even tops.

Ive even seen a guitar with a top made with each half a different tonewood.

Cheers Martin

Yes had thought of that too you could use a stiffer timber in the center where the stress is and something more resonant on each side.


Ross

Be careful....the play off with multi piece tops and backs is having more joins (=weak points). I wouldn't want more than one join in my bridge area. If getting a wide enough top out of four pieces I'd have the extra joins as close as possible to the periphery of the top.....maybe just "wings" aded to the lower bout.

Hi everyone,

This is a two piece top but the look is hot! http://mimf.com/cgi-bin/[email protected]@.2cb68084/0

Hi Martin,

I think that the joints would have to be really tight but a three piece top may be stronger than a two piece, particularly at the bridge, but as said before the joint must be first class. I certainly raises all sorts of aesthetic possibilities,

Sebastiaan

I dont quite see how having three joints in your bridge area is going to make the area stronger than having a single centre seam.

Youll notice that alot of makers run reinforcing diamonds along the centre seam in the lower bout area...I do it myself. This is done for a reason.

Originally Posted by kiwigeo

Yes of course. If the billet is smaller than what is usually milled for tops and backs then a three piece back is quite a sensible way to go. Torres and other famous luthiers often made three or four piece backs and at times even tops.

Ive even seen a guitar with a top made with each half a different tonewood.

Cheers Martin

Martin D35's I think have 3 piece backs, perhaps they do this with other models as well.

Ross,
There is nothing wrong in a three piece sound board, in fact in the future 3 pieces will be the norm once we run out of the large old growth trees.
Regards Bob,

Originally Posted by woodturner777

Ross,
There is nothing wrong in a three piece sound board, in fact in the future 3 pieces will be the norm once we run out of the large old growth trees.
Regards Bob,

Thanks I kind of thought that there may even be a tiny increase in strength but I am not having that arguement here !
Like a lot of things we do or are expected to do the reasons if they exist have been lost in myth and time and I am the sort of person who has to ask why and if the best answer I get is something like "Because that is the right way " then I feel compelled to try to test the theory.
I can see why visually it might be deemed preferable to have only 2 pieces but I can see some instances where 3 pieces might even look better.

Ross

Hi there

Here is a guitar I made about 12 years ago now, that has a nine peice top!
Sun, Moon and Star

I only had a narrow peice of WRC that I cut into strips. As you can see the colour gradient was strong in the WRC so it gave a nice effect of stripes. The guitar sounds great and has stood the test of time. I have made a few guitars with multiple peice tops in my early days and they have all performed functionally as well as the 2 peice tops.
I believe in being creative and using what you have available. Just because something is not the norm does not mean it can't be done, and done well, thats how we progress as a species is it not?. So I say, experiment and go for it!

Originally Posted by Wildwood

I have made a few guitars with multiple peice tops in my early days and they have all performed functionally as well as the 2 peice tops.
I believe in being creative and using what you have available. Just because something is not the norm does not mean it can't be done, and done well, thats how we progress as a species is it not?. So I say, experiment and go for it!

Hi Wildwood,

Thanks for posting this, it is a beautiful guitar. ive also trawled your website and I think your work is bluddy marvelous.

There is a conservatism in the lutherie world that sometimes I dont understand. For the guys who want to make a living selling to mainstream artists this is inevitable. For the weekend wood villian like myself there are really no boundaries. I personally have no interest in recreating what Fender, Gibson etc have done. Im not a factory so I will never produce repeatable standard instruments anyway.

Have you ever used timbers from differing species? I have a piece of Monterey Cypress and some lovely highly silked WRC that Im toying about joining. My only concern is differentials in expansion/contraction as the weather changes? Part of my thinking is joining on the diagonal, eg chevrons. Do you have any advice?

Sebastiaan