He sounds older, nastier, as if the hellhound on his trail that he sang about had caught up to him already. He sounds, in essence, like a different man. Speeding up the recordings, if it happened, changes how we hear blues and rock history. If Gibbens is right, this would change the way we hear and understand the blues. Johnson’s raw, on-the-edge voice? Fake. The wild guitar runs that made thousands of aspiring guitarists’ fingers bleed? Ditto. Theories abound on why these manipulations might have occurred: It was an equipment failure, perhaps. Some say the recordings had to be sped up to fit on 78-rpm records, which, at the time, had a maximum playing time of three minutes. Others contend it was a conscious decision to make the songs more commercial.