# US 4,391,346 A · Loud-speaker

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- Number: US 4,391,346 A
- Document ID: US4391346A
- Status: Granted
- Kind: A
- Application number: 06/192,187
- Filed: 1980-09-30
- Granted: 1983-07-05
- Earliest claimed: 1979-10-04
- Assignees: Naoyuki Murakami
- Inventors: Naoyuki Murakami; Hiroshi Zyo
- Web page: https://patentgrep.com/patent/US4391346A

## CPC

- H04R 1/24: Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges
- H04R 1/227: {using transducers reproducing the same frequency band}
- H04R 1/2819: {for loudspeaker transducers}
- H04R 1/30: Combinations of transducers with horns, e.g. with mechanical matching means {, i.e. front-loaded horns}(horns in general G10K; {transducer enclosures or mountings using a back-loaded horn H04R1/2861; application of horns as guiding means to obtain a predetermined directivity characteristic H04R1/345})
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)

## Abstract

A loud-speaker of a closed or a bass-reflex type, wherein a plurality of speaker units are intensively arranged behind an opening of a baffle board or a throat of a sounding horn with the sound wave radiating direction thereof being concentrated toward the center axis of the opening of throat, and the total area of the entire diaphragms of the speaker units is made substantially equal to, or larger than, the area of the opening or throat.

## Claims

### Claim 1

A loudspeaker, comprising:
(a) a casing for accommodating therein speaker units, said casing being enclosed by walls on all four sides and back side, except for the front part;
(b) a baffle board provided at the open front part of said casing, said baffle board having an opening formed therein opening into the ambient, said opening lying in a plane substantially parallel to the said back wall and being symmetrical about a line perpendicular to said back wall;
(c) a plurality of speaker fitting panels mounted around and behind said opening formed in said baffle board at an angle to said baffle board diverging in the direction of said opening, and a back fitting panel mounted on said speaker fitting panels parallel to said back wall; and
(d) a plurality of speaker units intensively mounted on said speaker fitting panels around and behind said opening in said baffle board, and a back speaker unit mounted on the said back fitting panel, the total area of the entire diaphragms of said speaker units being substantially equal to, or larger than, the area of said opening in said baffle board, the sound wave radiating direction of said speaker units mounted on said speaker fitting panels being concentrated on a single imaginary point behind the plane of said opening in the baffle board, hence within the ambit of the space defined by said speaker fitting panels and on the said line perpendicular to the back about which the said opening is symmetrical, and the sound wave radiation direction of said back speaker unit being alone said line.

### Claim 2 (depends on 1)

The loudspeaker as set forth in claim 1, wherein the total area of the entire diaphragms of said speaker units is larger by about 1 to 1.5 times than the area of said opening in said baffle board.