Sir George is one of the most prolific, diverse, and consistent producers in the world. In addition to the Beatles, Jeff Beck, and all the rest of the pop/rock stuff he produced (there is a lot), he is also one of the worlds best classical producers (he actually considered this to be his "career"), and he got his start (late `40s-early `50s) producing comedy records.
Two of my favorite of his (recent) albums were "Glory of Gershwin," by Larry Adler, and "In My Life," by Sir Martin himself. "Glory of Gershwin" was an eightieth birthday album by Adler, who was a close friend of George Gershwin's, and probably the best chromatic harmonica player in the world. The album is duets by Adler and various well known musicians, doing Gershwin covers. High points include "But Not for Me," sung by Elvis Costello, and "My Man's Gone Now," Sung by Sinead O'Connor. Also Larry Adler and George Martin's version of "Rhapsody in Blue," though I wish they had not cut out so much of the piece. After the first time Gershwin and Adler played "Rhapsody in Blue," together (back in the 1920's) Adler was constantly begging Gershwin to write a piece for chromatic harmonica, and Gershwin would always respond, "I already have, Rhapsody in Blue."
"In My Life" was to be the last album George Martin produced (I have not noticed him changing that decision). It is an album of Beatles songs, with various people covering them. Highlights would be "Come Together," sung by Robin Williams and Bobby McFerrin, and Jeff Beck playing "A Day in the Life." There is also a version of "I am the Walrus," sung by Jim Carrey, and while I am not a huge fan of Jim Carrey, I like the track. There are also a number of Martin's orchestral arrangements of Beatles songs (he did all of the orchestral arrangements for the original recordings, of course). He did this album, intending it to be his last album. He said, "There has to be a last album, so I would like to choose which one it is."
George Martin is a genius of a producer, a consummate musician, composer, and orchestrater. In addition to this, he has owned two of the world’s great recording studios (Air Montserrat, and Air London).
Bob Rock is, as near as I can tell, a passable guitar player, who tries like hell to emulate Mutt Lang, and can't quite get there. Of course, he can sell records, so I guess it does not really matter, right? I can't think of an album he has done which I am overly fond of (and I do like loud music, so it is not a genre thing). He certainly is not as diverse, nor as knowledgeable, about music as Sir George Martin, nor does he have 50+ years of amazingly good recordings behind him.
I got to do lights for one show for Sir George when he was touring, shortly after he retired. He was talking about the making of "Sgt. Pepper's Lonely Harts Club Band." I spoke with him very briefly after the show, and he was a kind, gracious, confident, and honest gentleman. He asked about my (then) interest as a producer. He was encouraging of this interest, far more so then many producers and engineers who are far less famous. He also had a handshake which was surprisingly firm for such an excellent piano player (most really great players seem to have handshakes like limp salmon, due to their concern for their hands.) He has an incredibly engaging personality. It is a shame his hearing lose (it is quite severe) has forced him to give up producing.
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"Cowards can never be moral."
M.K. Gandhi