H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
H04R1/00—Details of transducers, loudspeakers or microphones
H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
H04R1/345—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means for loudspeakers
Matrice a structure superficielle destinee a la production de gravures estampees sur des panneaux comprimes en matiere plastique, des stratifies de matiere plastique ou equivalents, et procede de fabrication d'une telle matrice
Procédé de fabrication d'un article de confection, appareil pour la mise en oeuvre du procédé et article obtenu au moyen du procédé de fabrication.