Abstract: A clarinet barrel consists of two parts (2 and 3) screwed into each other. The inner part (2) carries a ring (8) with an outer thread (9) screwed into a ring-shaped part (14) of the outer part (3) provided with an inner thread (15). The inner part (2) has a cylindrical section (4) in which is arranged a sealing ring (21) that seals section (11) of the outer part (3). The bore M has the same size and no steps in the area of the inner bore of the sections (7), in the area of the ring (8) and in the area of a shoulder (16) adjacent to the ring-shaped part (15). The effective length of the clarinet barrel 91) may be changed and the clarinet may be tuned by rotating the parts (2 and 3) against each other.