Abstract:
A sound tube having two passages affords a compact arrangement for a combined receiver and ear-canal microphone assembly. The ear-canal microphone is positioned in line with the receiver but above the receiver&#39;s output port, and the sound tube connects both with the ear canal.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     When a hearing instrument is inserted in the ear canal, the canal may be “occluded,” i.e., blocked. This may cause the user to experience a hollow sound when speaking, a phenomenon called the “occlusion effect.” One solution is to provide a vent that allows the sound pressure that develops in the ear canal to escape. 
     The occlusion effect may also be addressed by using the resulting sound to electronically cancel or minimize its effect. An ear-canal microphone captures that sound in the occluded ear and the signal is provided to circuitry in the receiver that uses the ear-canal microphone signal to cancel the sound. (See, e.g., U.S. Pat. No. 6,937,738, issued on Aug. 30, 2005, for a “Digital Hearing Aid System,” incorporated here by reference.) 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a drawing of a combination receiver and ear canal microphone with a sound tube having a passage for the ear canal microphone; 
         FIGS. 2 and 3  are drawings of the receiver and ear-canal microphone; 
         FIG. 4  is a drawing of a sound tube with an ear-canal microphone passage; 
         FIG. 5  is a sectional view of the assembly of  FIG. 1 ; and 
         FIG. 6  is a cross-sectional view of a hearing instrument shell positioned in an ear canal, containing the assembly of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE INVENTION 
     A combined receiver ( 100 ), sound tube ( 200 ), and ear-canal microphone ( 300 ) assembly  10  is illustrated in  FIG. 1 . Wiring  302  carries the output signal from terminals  304  of the ear-canal microphone  300  to terminals  102  on the receiver  100 . The receiver  100  and the ear-canal microphone  300  are shown apart from the sound tube  200  in  FIGS. 2 and 3 , although the receiver  100  and the microphone  300  are positioned spatially with respect to each other as they are in the combined assembly of  FIG. 1 . 
     Mounting studs  104  for the receiver  100  are shown in  FIGS. 2 and 3 . These are described in U.S. Patent Application Publication No. 2005/074138, dated Apr. 7, 2005, incorporated by reference herein. 
     Both the receiver  100  and the ear-canal microphone  300  have sound ports. In  FIG. 3 , a receiver output port  106  is located on the receiver  100  under the ear-canal microphone  300  and the ear-canal microphone  300  has an ear-canal input port  306 . 
     The sound tube  200  is shown separately in  FIG. 4 . The tube  200  may have a generally cylindrical cross-section subdivided by a divider  202  to provide a receiver passage  210  for the output of the receiver  100  and an ear-canal microphone passage  220  for the input to the ear-canal microphone  300 . The receiver passage  210  also has a receiver aperture  212  at one end and a hearing instrument aperture  214  at the other end. Similarly, the ear-canal microphone passage  220  has an ear-canal microphone aperture  222  at one end and a hearing instrument aperture  224  at the other end. When the assembly  10  is positioned in the hearing instrument ( FIG. 6 ), the apertures  214  and  224  connect passages  210  and  220 , respectively, with the ear canal. 
     The sound tube  200  also has a receiver flange  230  and a receiver platform  232  extending outwardly from the receiver flange  230 . Together, the receiver flange  230  and the platform  232  form a right-angle  234  and accept the receiver  100 , providing a positive registration for the receiver  100  with the sound tube  200  as well as vertical alignment of the receiver output port  106  with the receiver aperture  212  of the receiver passage  210  (see these elements in  FIG. 1 , as well). 
     As shown in  FIGS. 1-3 , the receiver  100  and the ear-canal microphone  300  are generally adjacent and positioned in tandem, i.e., one behind the other. To accommodate the ear-canal microphone  300  with the receiver  100  positioned on the receiver flange  230 , a portion of the sound tube  200  is cut back from the location of the receiver flange  230 , yielding an ear-canal platform  242  above the receiver passage  210 . 
     As further illustrated in  FIG. 4 , an ear-canal flange  240  is located at the edge of the cutaway portion (the ear-canal platform  242 ). The ear-canal platform  242  together with the ear-canal flange  240  provide a mounting location for the ear-canal microphone  300  as well as vertical alignment for the ear-canal input port  306  with the ear-canal aperture  222  of the ear-canal microphone passage  220   
     The receiver  100 , the ear-canal microphone  300 , and a cross-section of the sound tube  200  are shown in  FIG. 5 , taken according to the section indicated in  FIG. 1 . Note the divider  202  separating the receiver passage  210  from the ear-canal microphone passage  220 . As can be seen from  FIGS. 4 and 5 , the receiver passage  210  and the ear-canal microphone passage  220  are separate and therefore acoustically isolated from each other. 
     The combined receiver, sound tube, and ear-canal microphone assembly  10  is shown in  FIG. 6  in a hearing instrument shell  400  positioned within an ear canal  20  (the relatively-thick lines above and below the shell  400  depict the walls of the user&#39;s ear canal  20 ). The sound tube  200  exits the shell  400  at a receiver hole  402 . Also shown is an optional vent  404 . 
     An additional benefit of the combined receiver and microphone assembly  10  is realized during assembly of the hearing instrument. In  FIG. 6 , the ear-canal microphone  300  resides in an optional recess  406  in the shell wall  408 . When the assembly  10  is inserted into the shell  400 , the shell  400  shown in  FIG. 6  requires that the ear-canal microphone  300  slip into the recess  406 , thus orienting the assembly  10  radially with respect to the sound tube  200 .