Patent ID: 8404957

Claim:
A drumhead assembly comprising: a fixed support ring encircling a central assembly axis; a tuning assembly encircling said central assembly axis, said tuning assembly having a lower mouth, fixed in position adjacent to said fixed support ring, and an axially adjustable upper mouth, said tuning assembly comprising: a circumferentially-fixed ring having a circumferentially-fixed annular inclined-plane surface, radially inclined at a first angle with respect to said central assembly axis; a circumferentially-variable ring having a circumferential annular inclined-plane surface, radially inclined at a second angle, supplementary to said first angle with respect to said central assembly axis, said circumferentially-variable ring being positioned such that at least a portion of said circumferential annular inclined-plane surface contacts at least a portion of said circumferentially-fixed annular inclined-plane surface; an adjustable circumferential-tensioning assembly configured to generate adjustable circumferential deflection of said circumferentially-variable ring, thereby causing said circumferential annular inclined-plane surface to traverse said circumferentially-fixed annular inclined-plane surface, generating an adjustable axial displacement force directed away from said fixed support ring; and an annular drumhead-contact surface encircling said upper mouth and coupled with said circumferentially-variable ring such that said adjustable axial displacement force causes axial displacement of said annular drumhead-contact surface between a minimum distance and a maximum distance from said fixed support ring; and a drumhead stretched across said upper mouth and said annular drumhead-contact surface, said drumhead having a restrained periphery positioned outside said tuning assembly and restrained with respect to said fixed support ring such that when said annular drumhead-contact surface is axially displaced to said minimum distance or said maximum distance, said annular drumhead-contact surface urges a central portion of said drumhead away from said fixed support ring under low tension or high tension, respectively.