If you want to be strict about it, straight blues is nothing but I, IV and V dominant 7ths; there are three progressions: 12 bar, 12 bar ‘quick change’ and 8 bar, all with a dotted-eighth shuffle rhythm. (ant, dead ant, dead ant, etc.) But if I think real hard, it’s only a very few blues artists that did just that and nothing else, playing shuffles all night long; Jimmy Reed comes immediately to mind; everybody else mixed in a little something different. Maybe there’d be some funk, latin, R&B or even disco, but most were very careful not to play any rock’n’roll.
As a young blues artist, I had to work out how NOT to do any rock; it seemed important, at the time; there are STILL purists who reject Stevie Ray Vaughan and Jimi Hendrix as blues musicians. I believe it was Howlin’ Wolf that said, “Rock’n’roll is nothing but the blues, played too loud and too fast”. He was onto something. There are some hallmarks that differentiate rock from blues, and I’ve compiled an incomplete list.
- Ground Zero is straight eighth notes played against swung sixteenths; this was the innovation Chuck Berry and Johnnie Johnson were known for, though they didn’t make it up from whole cloth-others had the pieces. “Shuffles are old-fashioned, man!”
- Rock’n’roll was influenced by country music, and vice-versa; Chuck Berry (that guy, again) and Carl Perkins were at either end of the teeter-totter, Chuck injecting country melody and storytelling in his blues in an effort to broaden his appeal to, let’s say a paler audience, and Carl Perkins infusing his hot hillbilly licks with blues rhythms to get the kids at the sock hop jumpin’.
- Rock tempi tend to speed up, creating a sense of anticipation; good rock drummers pull back the reins at the turnaround or the end of a verse/chorus. In the blues, you got to be a steady rollin’ man. Or gal.
- Rock drums are mixed louder, and vocals are mixed like the other instruments. The first half of the technique was pioneered by Bo Diddley and the latter part brought to fruition by The Rolling Stones, who were trying to play blues, but from an English perspective. Unlike blues, country, jazz or pop, or really any music that came before, rock music is mixed from the drums upward, rather than around the vocal. In the Stones’ case, there was a side benefit that Mick Jagger’s lyrics were basically unintelligible over AM radios, and listeners would call the station to request the song, to try to figure out what Mick was singing.
- I’ll probably add to the list.
Twang Fu 