Double Bass Extention

I just read this in Wikipedia. I really had no idea. *blush* Oh, had I known...

>>>In the United States, Canada and United Kingdom, most professional orchestral players use four-string double basses with an "C extension" which extends the lowest string down as far as low C, an octave below the lowest note on the cello (more rarely, this string may be tuned to a low B). The extension is an extra section of fingerboard mounted up over the head of the bass, which requires the player to reach back over the pegs to play, or to use a mechanical lever system.

That's why there is scordatura. ;)

I've seen those extentions before ... almost always a classical player, guess the jazz guys havn't adopted the really LOW hertz....