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Publication of BE450084ApublicationCriticalpatent/BE450084A/fr
H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; 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
G—PHYSICS
G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
G03B21/00—Projectors or projection-type viewers; Accessories therefor
G03B21/54—Accessories
G03B21/56—Projection screens
G03B21/565—Screens allowing free passage of sound
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Health & Medical Sciences
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Otolaryngology
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Physics & Mathematics
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Engineering & Computer Science
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Acoustics & Sound
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Signal Processing
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General Physics & Mathematics
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Diaphragms For Electromechanical Transducers
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