BINAURAL HEARING AID
 Inventors: Eric Lindemann; John L. Melanson,
both of Boulder, Colo.
 Assignee: AudioLogic, Inc., Boulder, Colo.
 Appl. No.: 123,499
 Filed: Sep. 17, 1993
 Int. CI.6 H04R 25/00
 U.S. CI 381/68.2; 381/68; 381/68.4
 Field of Search 381/68, 68.2, 68.4,
381/97, 98, 94, 104, 106, 107, 60, 68.1
 References Cited
U.S. PATENT DOCUMENTS
3,509,289 4/1970 Briskey et al. .
3,894,196 7/1975 Briskey .
4,531,229 7/1985 Coulter 381/68
4,773,095 9/1988 Zwicker et al. .
4,904,078 2/1990 Gorike .
4,947,432 8/1990 T0pholm 381/68.2
5,027,410 6/1991 Williamson et al 381/68.4
5,289,544 2/1994 Franklin 381/68
Primary Examiner—Curtis Kuntz
Assistant Examiner—Huyen D. Le
Attorney, Agent, or Firm—Homer L. Knearl
This invention relates to a hearing enhancement system having an ear device for each of the wearer's ears, each ear device has a sound transducer, or microphone, and a sound reproducer, or speaker, and associated electronics for the microphone and speaker. Further, the electronic enhancement of the audio signals is performed at a remote digital signal processor (DSP) likely located in a body pack worn somewhere on the body by the user. There is a down-link from each ear device to the (DSP) and an up-link from the DSP to each ear device. The DSP digitally interactively processes the audio signals for each ear based on both of the audio signals received from each ear device. In other words, the enhancement of the audio signal for the left ear is based on the both the right and left audio signals received by the DSP.
In addition digital filters implemented at the DSP have a linear phase response so that time relationships at different frequencies are preserved. The digital filters have a magnitude and phase response to compensate for phase distortions due to analog filters in the signal path and due to the resonances and nulls of the ear canal.