Advice about top bracing - Gibson Jumbos Vs Martin Dreadnoughts.
 

There are lots of dialogues here and elsewhere where original jumbo and dreadnoughts designs are seemingly confused.

The term "slope shoulder" seems to cause confusion not only by guitarists but by makers as well, when describing jumbo designs as slope.

As I'm sure, you are all aware, the big changes to flat tops occurred in the late '20s and early '30s when Martin introduced the 12 fret original dreadnought in 1931, then modified it to a 14 fret in 1934, when Gibson introduced the original Jumbo.

Many seem to describe the jumbo design as a slope shoulder dreadnought which strikes me as incorrect as referring to a Chevrolet Mustang, or a Ford Camaro etc.

However, I had the privilege to meet Bill Collings during his brief visit to the UK in 2015, and he spoke enthusiastically about his modifications to the bracing of his CJ line (j45 and J35 styles) which I confess that I didn't quite understand.

I'm wondering if anyone might be able to advise me of what, if any, design differences there were between the Martin bracing and the Gibson bracing patterns.

In fact, whilst the shape of the jumbo and the original dreadnoughts are rather similar, I'm also wondering if Gibson might even have copied the bracing designs from Martin?

If anyone knows anything about this I'd be much obliged.

Thanks in advance.