Question about braces

[Arnold Schnitzer]

There are two schools of thought about bass backs: 1) The back should be stiff and thick, so the top does the majority of the vibrating, and the bass will be more powerful; 2) The back should be treated like the top in that it vibrates and resonates freely, and the whole instrument will vibrate and the bass will be more powerful.

Several prominent bass makers carve their backs quite thick, and the tops fairly thin, adhering to school #1 above.

[Matthew Tucker]

So lets go for the more powerful one!

Interesting in Browns results is that the observation that the player is often able to mask or compensate for the difference in response between roundback and flatback so the differences are un-noticeable. I suppose if the back is contributing significantly to tone and volume you have a built in tone filter available with your left knee.

My observations of a free plate oscillating at a low resonant frequency, where the edges and centres of the plate can move by a centimeter or more, lead me to believe that a flexible rib structure helps allow the top to move, which is essential to transform string energy into movement of air, thus sound. The controlling factor is the strength of the box which must stay intact under high tension and compression. So you can see how both the schools of thought can work. But for me I think the back has a structural priority while its resonance is a by product of what's going on elsewhere.

Understanding its role in tone production I agree is not science yet!

[Pino Cazzaniga]

Put me in the second school, as I don't like heavy instruments, but top is moved mainly by bridge, back by soundpost (forgive the coarseness), and we have to consider the difference.
On flatbacks, sometimes I thought that a broken bend was due to the weather movements of the bend brace wood, locally stressing the groove.

[Brian Gencarelli]

Originally Posted by Arnold Schnitzer

There are two schools of thought about bass backs: 1) The back should be stiff and thick, so the top does the majority of the vibrating, and the bass will be more powerful; 2) The back should be treated like the top in that it vibrates and resonates freely, and the whole instrument will vibrate and the bass will be more powerful.

Several prominent bass makers carve their backs quite thick, and the tops fairly thin, adhering to school #1 above.

Maestro,

Which school do you subscribe to?

Brian

[Ken Smith]

Originally Posted by Brian Gencarelli

Maestro,

Which school do you subscribe to?

Brian

Is there a Column 'C' (school 3)?

[Arnold Schnitzer]

I personally treat the back like a secondary soundboard. I want resonance, and I also want some stiffness in the soundpost area. My back graduations (on roundbacks) would be considered thin by some.

[Ken Smith]

Originally Posted by Arnold Schnitzer

I personally treat the back like a secondary soundboard. I want resonance, and I also want some stiffness in the soundpost area. My back graduations (on roundbacks) would be considered thin by some.

Are the Backs that are thin as you decribe Braced in the center somewhat like a flatback?