Re: Meshuggah stuff..
The tuning for 7-strings (standard 1/2 step down):
Bb Eb Ab Db Gb Bb Eb
The tuning for 8-string (standard 1/2 step down):
F Bb Eb Ab Db Gb Bb Eb
***Note: On their last full-length CD, "Nothing," there were 4 tunings for the 8-strings. Low F, Low E, Low Eb, & finally Ultra Low Bb (one octave below the 7th string!!!). When playing live, they play all F, E, & Eb songs in F. For the one song in Ultra Low Bb, they just play it on a standard 7-string in "regular" Bb (no low octave).
Check out the Meshuggah FTP on the Meshuggah Forum for vids, Mp3s, etc.