Patent ID: 6995659

Claim:
A sound transducer comprising at least one sound unit based on at least one radially sound emitting diaphragm arranged in a substantially cylindrical or tubular form, said diaphragm consisting at least partly of electromechanically converting material capable of creating sound by changing its physical state upon electrical excitation, wherein within a single sound unit said diaphragm is arranged to be supported between an inner sound guiding sleeve and an outer sound guiding sleeve, said sleeves having substantially similar radial cross-sectional shape than said diaphragm, in order to form at least one axial acoustic channel between the diaphragm and at least one of said sleeves, so that the sound waves generated by the diaphragm are arranged to be guided along said acoustic channel out from the sound unit, and that at least at the exit side of said acoustic channel the axial ends of the diaphragm and the corresponding sound guiding sleeve are arranged to have mutual non-alignment in the plane perpendicular to the axis of the sound unit in order to reduce the acoustic mass that said acoustic channel represents.