Drop-D is one of the first alternate tunings that Dave used.
In order to tune to Drop-D you must change the pitch of the low E String of your guitar. You must tune your low E (top string of guitar) down 2 half steps. This means that when you play the 7th fret on the low E, it will sound the same as if you played the A string on your guitar open.
You cannot re-tune your guitar to Raised B. This is because a Raised B guitar has completly different string gauges in the normal positions. However, you can re-string your guitar to be a Raised B guitar.
The first thing you need is a set of Extra Light strings. You will also need an extra B-stringfrom a set of light strings. The gauge for that string must be .016. Take the low E string from the extra light set of string and throw it away. This is not needed at all. Next, start with the A string from the extra light set and string it in the low E position. Then you take the D string and string it in the A position. Basically what you are doing here is taking the each string and moving it 1 position up onthe guitar. This should leave the High E string position w/o anything there. Now comes in that extra B string. You take that extra string and string it into the High E position It will be a little weird to play because the highest position string will have a lower pitch than the one above it, but that's how Dave strings his guitar.
Tune to the following notes:
You cannot tune a normal guitar to Baritone tuning. A Baritone tuned guitar is a completly different guitar. It has a longer neck and the scale of the frets are different. The strings on a baritone guitar are also thicker giving it that low growling sound.
Every song that Dave Matthews plays on a Baritone guitar is tabbed for a Standard tuned guitar along with the Baritone tab.