The breton musicians have choosen the same drums as their counterpart of the scottish pipe-band because of the particular tone of those instruments.
They are carried.
A big drum (bass) gives the tempo, some tenor and alto drums nuance the rhythms given by side-drums.
The drums of the Kemper Bagad are from 6 to 8 side-drums, a player of tenor drum, two players of alto drum and one player of bass, this chapter may also express itself as an autonomous group of percussions. It may sometimes play with other rhytmic instruments (roto, tom ...).