Abstract: A loudspeaker includes a box-form structure made from stiff lightweight sheet material to define a plurality of faces, at least one face of the structure forming a panel-form bending wave acoustic radiator, and an electro-acoustic vibration transducer coupled thereto to apply bending wave energy to the radiator to cause it to radiate an acoustic output when an input signal is applied to the transducer. The box-form structure is collapsible, so that the box-form structure can be stored and transported in a flat form and erected as a box when required as a loudspeaker.

Abstract: A loudspeaker includes an assembly of at least two bending wave panel-form acoustic members each having a set of modes which are distributed in frequency. The parameters of at least two of the acoustic members are selected so that the modal distributions of each acoustic member are substantially different. The arrangement is such that the modal distributions of the assembly of acoustic members are interleaved constructively in frequency. A transducer applies bending wave energy to the acoustic members to cause them to resonate to produce an acoustic output. A method of making such a loudspeaker is also provided.

Abstract: A loudspeaker includes an assembly of at least two bending wave panel-form acoustic members each having a set of modes which are distributed in frequency. The parameters of at least two of the acoustic members are selected so that the modal distributions of each acoustic member are substantially different. The arrangement is such that the modal distributions of the assembly of acoustic members are interleaved constructively in frequency. A transducer applies bending wave energy to the acoustic members to cause them to resonate to produce an acoustic output. A method of making such a loudspeaker is also provided.

Abstract: A loudspeaker includes a box-form structure made from stiff lightweight sheet material to define a plurality of faces, at least one face of the structure forming a panel-form bending wave acoustic radiator, and an electro-acoustic vibration transducer coupled thereto to apply bending wave energy to the radiator to cause it to radiate an acoustic output when an input signal is applied to the transducer. The box-form structure is collapsible, so that the box-form structure can be stored and transported in a flat form and erected as a box when required as a loudspeaker.