A percussion beater cage has a first cage bar (1) positioned horizontally apart from a second cage bar (2) on at least one bar holder (3). The first cage bar is structured for attachment of a first acoustical trigger (5). The second cage bar is structured for attachment of a second acoustical trigger (6). The bar holder and optionally bar holders (12, 13, 32, 35) are structured for adjustable positioning of the first cage bar and the second cage bar a distance apart selectively for positioning the first acoustical trigger a desired strike-timing distance apart from the second acoustical trigger selectively. A base plate (4) is structured for attachment of a conventional foot pedal (7) for foot-actuating musical instruments that include base drums. The conventional foot pedals generally have a beater head (9) on a beater rod (8) actuated with the foot pedal for striking at least one acoustical trigger that is most commonly digital.