(under subclass 157) Subject matter wherein the diaphragm has areas of different material, shape or thickness which are united to form a vibratable partition.
(1) Note. Only one independent driver unit may drive the diaphragm. When the different sections are driven independently of one another, they are considered plural, independent diaphragms and classified in subclasses 144+.
(2) Note. The different sections may have different natural periods of vibration and thus produce sound waves within different frequency ranges.
