[iim7V7IM7]

But some builders don't use a transverse brace in their upper bout bracing design. There are alternative methods of handling the string load that may allow for enhanced upper bout movement when the fingerboard is elevated.

Originally Posted by billgennaro

This is what I've come to believe from reading I've done. The large transverse(?) brace that stretches across the entire top, just above the sound hole on a flattop guitar, creates a boundary which effectively stops the area above it from vibrating. So a fingerboard extension glued directly to the guitar's top in that area should not be a negative as far as tonal characteristics are concerned.