Guitars are tuned to Drop B, or Dropped B, by tuning down the top string two-and-a-half steps from standard tuning and the remaining five strings down by one-and-a-half steps. The final tuning, from low to high, is B-F#-B-E-G#-C#.
Drop B is an alternate guitar tuning often used by heavy metal bands. First, all strings are tuned down a minor third from standard tuning. Finally, the lowest string is tuned down a further step. Since Drop B tuning loosens guitar strings, using higher gauge strings, such as gauge 11, ensures there is enough tension in the strings to keep the guitar playable.