The bodhrán ( or ; plural bodhráns) is an Irish frame drum ranging from 25 to 65 cm (10″ to 26″) in diameter, with most drums measuring 35 to 45 cm (14″ to 18″). The sides of the drum are 9 to 20 cm (3½” to 8″) deep. A goatskin head is tacked to one side (synthetic heads or other animal skins are sometimes used). The other side is open-ended for one hand to be placed against the inside of the drum head to control the pitch and timbre. One or two crossbars, sometimes removable, may be inside the frame, but this is increasingly rare on modern instruments. Some professional modern bodhráns integrate mechanical tuning systems similar to those used on drums found in drum kits. It is usually with a hex key that the bodhrán skins are tightened or loosened depending on the atmospheric conditions.
