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View Full Version : Why bookmatch instead of one-piece?



PoiDog
10-19-2011, 08:10 AM
I was just wondering whether there was a reason other than aesthetics for builders to bookmatch the top and sides of a uke (or guitar, etc) rather than just use a single, unglued piece of wood?

Is it that finding a suitable piece of the proper dimension is too difficult, or that using the bookmatch process maximizes the usable amount of wood?

Much mahalos for your indulgence for what is basically just a "I wonder why ..." question.

gyosh
10-19-2011, 09:19 AM
This is second hand info so take it for what it's worth, but I read somewhere (see what I mean?) that the grain and there fore properties of a solid piece of wood might change too much across the instrument and it could affect the sound quality (more so for larger instruments like a guitar). Book matching might be done for better consistency? Like I said, it's second hand info.

olgoat52
10-19-2011, 09:31 AM
Finding instrument grade wood wide enough to span a back of a guitar would be almost impossible. On ukes, not as much but still a factor. Then there is the esthetic of book matching which many come to expect. I have never heard that book match is more stable or moves less than single piece.

Allen
10-19-2011, 10:20 AM
1. Smaller wood....easier and less expensive to source.
2. Some wood as you said will have an unacceptable difference in stiffness across a large expanse like on the lower bout of a large guitar.
3. Aesthetics can play a part, but that may or may not be just a happy coincidence of needing to be thrifty with the wood in the first place.

On small ukes like sopranos and sometimes concerts it's fairly easy to get single piece tops and backs in some species, and would be my preference.

However with the larger instruments and in some of the species you see today this is getting really hard to source, and the price is going through the roof. When the cost to the luthier for a really nice set of wood is $200 even when it's book matched, it puts the price of the finished instrument in the very pointy end of the market place.

Done properly there isn't any disadvantage to a book match. Millions of instruments are built this way.

ProfChris
10-19-2011, 10:44 AM
And if, at the bottom end, you're recycling stuff (wardrobes, shelves, whatever) even a soprano-sized slice can be hard to find. Plus the aesthetics of bookmatching are rather nice, particulary if there is a strong figure in the grain.

Pete Howlett
10-19-2011, 10:52 AM
I like one piece - less risk of seam separation - a mojor consideration because ukes go all over the world and clients are notorious for dessicating their homes in winter and allowing the humidity to rise in summer. When I exported to hawaii or japan i was quite happy - island to island as it were. Now I have stuff going to scandinavia I am really concerned so my fingerboard live on the storage heater and the dehumidifier is on all day and night.

Tor
10-20-2011, 02:39 AM
And then there's the Martin D-35 with its 3-piece back.

-Tor

(As for Scandinavia.. yes it can be terribly dry in the winter, particularly inland where it gets really cold. I for one keep my instruments in a humidity- and temperature-controlled room. Works great. The thing about living in a country with cold winters is that (reasonably new) houses are very well insulated, so there's no risk of cold surfaces on or inside walls, so using a humidifier doesn't cause condensation which could create mold problems.)

wolfybau
10-20-2011, 04:14 AM
thats an interesting question. As someone who has studied resonance and acoustics, I wonder how the symetry of the bookmatched wood affects the vibration of the soundboard. I would think it would have an affect on harmonics and sustain as it relates to frequency in the same way you get things like phase cancelations and such in a room with symetrical walls and structure. this applies to the symetrical shape of an acoustic instruments body shape and its aircavity , it sort of stands to reason that if there is a density and flex difference it the wood isnt symetrical it would affect the sound but I wonder if it creates enough of a difference for it to be detectable by the human ear? and is it a good or bad thing when it concerns the sound of an instrument?

ksquine
10-20-2011, 07:33 AM
You see quite a few soprano sizes with one piece tops/backs. For the larger sizes its hard to find wood consistent enough across the whole top.

southcoastukes
10-20-2011, 08:22 AM
... I wonder how the symetry of the bookmatched wood affects the vibration of the soundboard... it sort of stands to reason that if there is a density and flex difference ... the wood isnt symetrical it would affect the sound ...

When we first started building ukuleles we did semi-custom builds. We had a client that wanted a one piece back and top for a concert. When I asked my partner Omar about doing this, he replied in his most polite manner (the one that means "are you out of your mind?"), that of course we would do whatever the Senor wanted, but that I should inform him it wouldn't sound as good.

The expanation he then gave (in technical matters my Spanish sometimes precludes complete understanding) was pretty much what wolfy has speculated. More or less that grain pattern and stiffness need to be aligned from one side to the other so that sound waves will travel uniformly inside the body cavity.

Since I never suggested it again, I have no basis for comparison, but I would imagine the wider the board, the more important this would become.

PelicanUkuleles
10-22-2011, 08:12 PM
thats an interesting question. As someone who has studied resonance and acoustics, I wonder how the symetry of the bookmatched wood affects the vibration of the soundboard. I would think it would have an affect on harmonics and sustain as it relates to frequency in the same way you get things like phase cancelations and such in a room with symetrical walls and structure. this applies to the symetrical shape of an acoustic instruments body shape and its aircavity , it sort of stands to reason that if there is a density and flex difference it the wood isnt symetrical it would affect the sound but I wonder if it creates enough of a difference for it to be detectable by the human ear? and is it a good or bad thing when it concerns the sound of an instrument?

Makes me think the center line of a book matched top should be offset to accommodate the difference in vibrations between the treble and the bass sides. Unless one could control it with the grain density as it moves through a one piece top.:confused:

luthier
10-24-2011, 08:08 AM
It's mainly because bookmatched soundboards are what people used to see on guitars and violin families. On ukuleles, plates with lots of runout or spalted area or both are acceptable even for tops. Why? One can say uke lovers are not as obsessed with criterias such as minimal runnout, stiffness/weight ratio, blah blah blah... as guitar guys.

PelicanUkuleles
10-24-2011, 09:26 AM
My Kamaka pineapple and a standard soprano (both gold labels) have one piece tops and backs.
One could certainly save some time (and materials) building that way.
The non-pineapple soprano has the sweetest tone.
I haven't received it yet but I'll let you know how the pineapple sounds with it's one piece top. :cool:

Rick Turner
10-24-2011, 11:53 AM
A study of guitar and uke acoustics will show that there isn't really a bass side and treble side, as nice as that would be to imagine.

Also, many very fine violins have one piece backs, though one piece tops are very rare.

To me, it's just a "size matters" issue with regard to availability and even grain. I'm doing my soprano and tenor pineapple uke kits for the course I teach as one piece with Western red cedar tops and usually mahogany backs; they sound just fine. We do our new Compass Rose concerts as two piece and most of our tenors are two piece...but if I have wood that is fairly consistent all the way across and is decently quartered, I'll use it.