Rhythm and Blues vs Rock and Roll

[kiwlm]

What's the difference "musically" between the two?

I was reading this
http://www.binkie.net/wrdisc/Mr.%20Gone.html
when jaco said:
...because if there's a heavy feel, it's r&b, not rock. There's a difference between rhythm and blues and rock 'n' roll. I grew up playing nothing but colored music all my life and that's it.

So far, I would say that for RnB, the chord changes are not as rapid as Rock and Roll.

[Against Will]

Rock N Roll has a country influence. It was also co-opted by white culture in the USA, while RnB remained pretty closely tied with the african-american community.

There are similarities, without a doubt, at least between early versions of each genres. RnB retained the groove, while Rock became more straightforward.

[Folmeister]

R&B retains much of the influence of gospel and the spirituals that were at the core of African-American cultural life before the emergence of rock & roll in the early 1950s. Rock & roll is a hybrid form that took basic structural forms from traditional/country blues and added the electric sounds of Chicago blues (with a heapin' helping of rockabilly along the way). Another difference is in the intended audience. Rock & roll is what happens when well-fed, middle-class white kids get interested in the music of the ill-fed. ill-treated, and marginalized.