Originally Posted by: jiujitsu_jesusI know how to tune my E-string down to D, but how do you tune it down to Eb or C?[/QUOTE]
I'm assuming you're tuning it by using the open "D" string as a reference, and if so, do the same for Eb or C with the various strings. You'll find a C on the A at 3rd fret, and Eb at the 6th fret, or D string 1st fret, or both. Use multiple frets, strings, octaves, harmonics, and/or chords...whatever works. However I used to use cd's of Slayer or SRV as references for Eb tuning, as they both usually were.
[QUOTE=jiujitsu_jesus]And how do you play E-string power chords once you're in one of those keys?