381 / | HD | ELECTRICAL AUDIO SIGNAL PROCESSING SYSTEMS AND DEVICES |
150 | DF | ELECTRO-ACOUSTIC AUDIO TRANSDUCER {18} |
396 | DF | .~ Electromagnetic (e.g., dyynamic) {8} |
423 | DF | .~.~ Specified diaphragm shape or structure {6} |
424 | .~.~.~ Plural portions or sections {1} | |
425 | DF | .~.~.~.~> Honeycomb |