The Drum Tower stands a few hundred metres west of the Bell Tower and is generally the more rewarding of the pair: it sits right on the edge of the Muslim Quarter, and the view from the upper balcony down into the maze of food stalls and cooking smoke is one of the great Xi'an spectacles. Built in 1380 and the larger of the two towers, it once held a row of drums that were beaten at sunset to mark the closing of the city gates.
Inside, the upper floor displays a collection of antique Chinese drums and stages short percussion performances several times a day. Buy the combined Bell-Drum ticket if you want both.