Were Robert Johnson’s recordings sped up?

A post over on Boing Boing ("The last mystery of the blues: were Robert Johnson's recordings sped up?") drove me right to my sound editor to see how Robert Johnson's performances may have sounded different from his recordings. Here's the result:

Robert Johnson Speed Demo

The audio is a 30 second clip of "Sweet Home Chicago" played once at normal speed (i.e., the recorded speed) and then a second time about 20% slower (2 semitones lower). (Note: I didn't labor over the crossfade between the clips.)

Pretty interesting, if you ask me.


  1. The article has no mention of A 440 Hz tuning (US 1926) or A 435 Hz tuning (Austria 1885).

    Any string or wind player knows that instruments have limited flexibility. Even if Robert Johnson didn’t travel with a pitch pipe or tuning fork, the producers of his first or second recordings likely had something on hand.

    Jimmy Guterman at Boing Boing is exhausting the realm of perception, aka what sounds right. It’s awesome and convincing, but incomplete. If he could back that up with additional science I’d be more interested.

    I first heard Robert Johnson on second-hand cassette. I thought the cassette speed was screwed up.

  2. Interesting points, Ken. Considering how crazy his voice sounds on those recording, I just wanted to hear the difference. And I think the slowed down version sounds more natural.

  3. Yeah, thanks for posting your audio samples. Natural comes to my mind too.

    And as for the written/verbal accounts of people hearing Robert Johnson live; they would describe his voice as “high” and his fingers as “fast”.

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