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Old 02-17-2019, 03:44 AM
Henning Henning is offline
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Default Arching of the back

Hello, what is the purpose of the arching of the back?
Beside a slight increasing of volume of the resonance body.
If you take a guitar with a heavily arched back in both directions and compare it to one built in the exatly same manner and materials, what would the difference be in comparison to one with a completely flat back?
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Old 02-17-2019, 06:48 AM
charles Tauber charles Tauber is offline
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Added strength. An arched shape is more resistant to deformation than a flat one. Increases, somewhat, crack resistance since, when shrinking , it can flatten, whereas a flat back has no where to shrink. Theory is that a back not parallel to the top alters sound waves in the body.

Last edited by charles Tauber; 02-17-2019 at 06:53 AM.
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Old 02-17-2019, 07:26 AM
DCCougar DCCougar is offline
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Quote:
Originally Posted by charles Tauber View Post
Added strength.
Yeah, good point. Guild has famously and successfully made arch-back guitars for many years, and they generally sound fabulous (despite the backs being laminate). Not only are the backs arched, they're braceless, which I think makes a big difference, too.
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Old 02-17-2019, 10:40 AM
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Rodger Knox Rodger Knox is offline
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I agree with Charles, except I believe it's more for resistance to cracking, the increase in strength is not that significant. The exception to that is the Larsen Brothers design of a 12' cylindrical radius for the top, which would be much stiffer longitudinally than the typical 20'+ spherical radius. Which is more important is not really a point worth debating.
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Old 02-17-2019, 01:16 PM
bufflehead bufflehead is offline
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My Taylor BBT has an arched, laminated back which is strong enough that the back needs no internal bracing. Lightens the guitar up, which is a good thing for a travel guitar.
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Old 02-17-2019, 01:18 PM
Alan Carruth Alan Carruth is offline
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Braceless arched backs, whether laminate or carved, work differently than braced ones. In essence, they are using arch height and plate thickness to get the stiffness that a 'flat' back gets from bracing. There are advantages and disadvantages to each system, in terms of acoustics, strength, material costs and the time required to make them.
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