(under the class definition) Subject matter including at least two separate means that can be vibrated by sound waves or produce sound waves.
SEE OR SEARCH THIS CLASS, SUBCLASS:
148, for a single diaphragm and an enclosure with plural sound emitting portions.
163, for plural dependent diaphragms.
SEE OR SEARCH CLASS
381, Electrical Audio Signal Processing Systems and Devices, 150+, for instruments designed to transform variable electrical current or potential into sound in combination with means to intensify the sound by mechanical means. Note especially subclasses 337+ for such combinations having sound resonators as the intensifying means. Also subclasses 193 and 202+ for diaphragm and support means with electrical means to move the diaphragm.
