Both rapper and longsword dances are typically danced to tradtional English folk tunes, usually played on a violin, melodeon, or concertina. Many other instruments may be used, such as drums, flutes, and guitars. Tunes from other countries and traditions, and even modern tunes, can be used.
Almost universally, the music will be played live. It is extremely difficult to perform rapper or longsword to a pre-recorded track. During a performance, because of the intricacies of many of the figures, the differing abilities of the individual dancers, or the sheer bad luck to have a minor (or major!) mishap which causes a minor (or major!) delay, the musicians have to be ready to react at a moment’s notice. They may need to slow or speed up to match the dancers, repeat a phrase while a mishap causes a figure to be repeated, change the tune if a figure is performed out of sequence, or any number of other possibilities.
A dance may be accompanied by a single musician, a full band, or anything in between. Often the dancers will ‘march on’ to the performance area led by the music, or the musicians will begin with a cue from the dancers. Most dances, unless quite short, will include a number of different tunes.