Number Nine: Yankee Announcer's Voice on Beatles' White Album

I'm convinced that the voice saying "number nine" repeatedly in the Beatles' White Album song "Revolution 9" is none other than the Yankees PA announcer Bob Sheppard. The White Album was put out in '68, so I'm guessing that the voice is an audio clip from Sheppard announcing a Roger Maris at bat sometime in '66 or earlier.

I Googled and surfed to find some confirmation of this. I did find a YouTube clip of him announcing a game in '06. At about 0:41 on this clip you can hear him announce a Texas Ranger player who wears uniform number nine. Forty years later, it sounds just like the White Album. After my discovery, I found this on Wikipedia.