Patent · US Expired

Sound reproducing apparatus

US4972489A · kind A · utility

20Cited by
7References
8Claims
0Family size

Assignee

Inventors

Key dates

Filing dateSep 21, 1989
Grant dateNov 20, 1990
Priority date
Expiry dateSep 21, 2009

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH03G5/025
  • WIPO fieldAudio-visual technology
  • WIPO sectorElectrical engineering

Abstract

A sound reproduction system suitable for automobile, the reproduction system having a band-pass filter, a phase-shifter for shifting the output of the band-pass filter and a mixer which mixes the output of the phase-shifter with the original audio signal at a suitable mixing ratio, whereby a low frequency standing wave which is generally produced in the small automobile room may be eliminated, thereby providing a desirable frequency response characteristic.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.