Canal hearing devices with improved seals

1. A hearing device, comprising:

a hearing device core defining an exterior surface, a lateral and a medial end, and including a battery, a microphone and a receiver;

a seal, movable between an uncompressed state that defines a first cavity volume and a compressed state that defines a second cavity volume that is less than the first cavity volume and including a shell wall and defining an outwardly facing exterior surface, an inwardly facing interior surface, a first end and a second end, mounted on the hearing device core with the shell wall first end secured to the hearing device core, the shell wall second end located in spaced relation to the hearing device core and located between the lateral and medial ends of the hearing device core, and a cavity that has an opening located at the shell wall second end defined between the hearing device core exterior surface and the shell wall interior surface; and

a volume of viscous medium, which is less than the first cavity volume, located within the cavity between and in contact with the hearing device core exterior surface and the shell wall interior surface.

2. The hearing device of claim 1 , wherein

the volume of viscous medium within the cavity between the hearing device core exterior surface and the shell wall interior surface is the only viscous medium associated with the hearing device.

3. The hearing device of claim 1 , wherein

movement of the seal from the uncompressed state to the compressed state forces a portion of the volume of viscous medium through the cavity opening.

4. The hearing device of claim 3 , wherein

the seal comprises a medial seal that is oriented such that the first end defines the medial end and the second end defines the lateral end;

the hearing device further comprises a lateral seal, including an outwardly facing exterior surface, mounted on the hearing device core such that there is a space that extends from the cavity opening to the lateral seal exterior surface; and

the portion of the volume of viscous medium that is forced through the cavity opening is forced into the space that extends from the cavity opening to the lateral seal exterior surface.

5. A hearing device, comprising:

a hearing device core defining an exterior surface and including a battery, a microphone and a receiver;

a seal, including a shell wall and defining an outwardly facing exterior surface, an inwardly facing interior surface, a first end and a second end, mounted on the hearing device core with the shell wall first end secured to the hearing device core, the shell wall second end located in spaced relation to the hearing device core, and a cavity that has an opening located at the shell wall second end defined between the hearing device core exterior surface and the shell wall interior surface, the shell wall is formed being at least in part from a resilient material having sound attenuating properties and water vapor transport properties, defining a longitudinal axis and a perimeter that extends around the longitudinal axis, and being configured to distribute compressive forces applied to the shell wall perimeter such that when the shell is positioned in an ear canal, the shell wall dynamically conforms to changes in the shape of the ear canal and exerts a spring pressure on the ear canal walls that is between about 2 mmHg and about 12 mmHg; and

a volume of viscous medium, located within the cavity between the hearing device core exterior surface and the shell wall interior surface, that increases the sound attenuation and water vapor transport properties of the hearing device to levels above that provided by the shell wall without increasing the pressure exerted on the ear canal walls by the shell wall.

6. The hearing device of claim 1 , wherein

the hearing device core defines a longitudinal axis and the hearing device core exterior surface defines a perimeter that extends around the longitudinal axis;

the cavity extends around the entire perimeter of the hearing device core exterior surface; and

the cavity opening extends around the entire perimeter of the hearing device core exterior surface.

7. The hearing device of claim 1 , wherein

shell wall interior surface includes a plurality of scallops.

8. The hearing device of claim 1 , wherein

the shell wall is formed from elastomeric foam.

9. The hearing device of claim 1 , wherein

the seal and viscous medium together cause acoustic attenuation that is at least 3 dB greater than the acoustic attenuation caused by the seal alone.

10. The hearing device of claim 1 , wherein

the viscous medium comprise a gel.

11. A hearing device, comprising:

a hearing device core defining an exterior surface and including a battery, a microphone and a receiver;

a seal, including a shell wall and defining an outwardly facing exterior surface, an inwardly facing interior surface, a first end and a second end, mounted on the hearing device core with the shell wall first end secured to the hearing device core, the shell wall second end located in spaced relation to the hearing device core, and a cavity that has an opening located at the shell wall second end defined between the hearing device core exterior surface and the shell wall interior surface; and

a volume of gel, selected from the group consisting of clay/glycerin gel, carbopol/glycerin gel, agar/glycerin gel and polyvinyl alcohol gel, located within the cavity between the hearing device core exterior surface and the shell wall interior surface.

12. The hearing device of claim 10 , wherein

the gel is selected from the group consisting of viscous gel and viscoelastic gel.