Abstract: The instrument includes a support structure formed of telescoping legs enabling height adjustment of the bed supporting the bars. The bars are strung on lines supported on bar mounts having resilient material in engagement with the lines preventing transmission of vibration from the bars to adjacent bars and to the support structure. A dampening rail including a fluid-filled bladder extends the length of the instrument in underlying relation to the adjacent inner ends of the two rows of bars and is spring-biased into engagement with the bars. A pedal, selectively displaceable along a longitudinal support bar, is used to engage and disengage the bladder relative to the bars. The pedal includes a fulcrum assembly for adjustment of the feel of the pedal.