A
loudspeaker comprises a panel member (11, 21, 31, 41, 61, 71, 81, 91) as resonant acoustic radiator relying on bending wave action and a driver (12, 22, 32, 42, 62, 72, 82, 92) coupled to the panel member to cause bending
waves therein. The panel member has its
mass and / or bending capability of the panel member locally altered or otherwise different, particularly locally of the driver as coupled to the panel member. Local holes (16, 26, 36, 46), affixed
mass (66) or affixed damping material (76) are effective to reduce
high frequency due to drumming effects at the driver
coupling (17, 37, 47, 67, 77, 87).