SPEAKER BOX

• US 3,729,061 A
• Filed: 02/26/1971
• Issued: 04/24/1973
• Est. Priority Date: 02/27/1970
• Status: Expired due to Term

• Current Assignee: Yutaka Tamura
• Original Assignee: Yutaka Tamura
• Inventors: Tamura, Yutaka
• Primary Examiner(s): Tomsky, Stephen J.
• Application Number:
  US05/119,333
• Time in Patent Office: 788 Days
• Field of Search: 181/31B,31R
• US Class Current: 181/146
• CPC Class Codes: H04R 1/26 Spatial arrangements of separate transducers responsive to two or more frequency ranges
• CPC Class Codes: H04R 1/2826 for loudspeaker transducers

Abstract

A speaker box has a baffle plate with a speaker mounting hole provided in either the upper or lower portion. A duct for inverting a phase of sound in the neighborhood of the lowermost resonant frequency of the speaker is provided to introduce the sound outside the speaker. Sound absorbing means is provided on the duct so as not to unduly interfere with the sound discharged from the front surface of the speaker in the range that the sound discharged rearwardly of the speaker is of a higher frequency band than the lowermost resonant frequency when the speaker mounting hole is provided in displacement in the neighborhood of the duct.

Claims

1. In an essentially closed speaker box for projecting sound, the improvement comprising:

a baffle plate forming one wall of said box, said baffle plate having an off-center speaker mounting hole;

a speaker capable of projecting a frequency range of sound mounted in the speaker mounting hole;

duct means carried by said speaker box and extending inwardly of said baffle plate for inverting a phase of sound approximately of the lowermost resonant frequency of the speaker and for introducing the sound outside of the speaker box;

a mounting plate fixed to said duct means rearwardly of said baffle plate and extending towards said speaker; and

sound absorbing means lining said duct means and said mounting plate to prevent interference with the sound phase discharged from the front surface of the speaker in a range where the sound phase discharged is higher than the lowermost resonant frequency when the speaker is mounted adjacent to the duct means.

2. A speaker box as set forth in claim 1 including woofer means installed in the lower portion of the baffle plate for phase inversion.

3. A speaker box as set forth in claim 2 wherein a top wall and rear side wall are lined with sound absorbing material.

4. A speaker box as set forth in claim 3 including an intermediate frequency speaker and tweeter mounted respectively above the woofer.