Method and apparatus for determining in situ the acoustic seal provided by an in-ear device.

• US 20020076057A1
• Filed: 12/20/2000
• Published: 06/20/2002
• Est. Priority Date: 12/20/2000
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: Sonomax Hearing Healthcare Inc. (Sonomax Technologies, Inc.)
• Inventors: Voix, Jeremie
• Granted Patent: US 6,687,377 B2
• Time in Patent Office: Days
• US Class Current: 381/60
• CPC Class Codes: A61F 11/08 internal, e.g. earplugs
• CPC Class Codes: A61F 11/085 including an inner channel
• CPC Class Codes: H04R 2460/15 Determination of the acoustic seal of ear moulds or ear tips of hearing devices
• CPC Class Codes: H04R 25/30 Monitoring or testing of hearing aids, e.g. functioning, settings, battery power
• CPC Class Codes: H04R 25/656 Non-customized, universal ear tips, i.e. ear tips which are not specifically adapted to the size or shape of the ear or ear canal

Abstract

The present invention provides an apparatus for determining in situ the acoustic seal provided by an in-ear device of a hearing protection/aid nature inserted into the ear canal of an individual. The in-ear device having a sound bore with an environment opening and an ear opening outside and inside the ear canal respectively, the environment opening is adapted to be removably engaged by a remote device such as a sound measurement device, a filter device, an amplifier device, a plug device and the like. The apparatus includes a sound measurement device having a probe microphone and a reference microphone isolated from each other and connected to a data processing unit having a control box and a speaker, both connected to a computer unit. Both microphones are adapted for measuring sound pressure levels inside said ear canal and outside in close proximity of said in-ear device respectively, the sound pressure levels corresponding to a known noise signal created by the speaker. The data processing unit being adapted for recording and processing the sound pressure levels read by both microphones corresponding to said known noise signal to provide a corresponding calculated value of a sound pressure level difference provided by the in-ear device. Used in conjunction with an expandable in-ear device, the apparatus monitors the acoustic seal in real time during the occlusion process of the in-ear device and determines when to stop the process. The present invention also refers to a corresponding method for determining in situ the acoustic seal provided by an in-ear device.

Claims

1. An apparatus for determining in situ an acoustic seal provided by an in-ear device inserted into an ear canal of an individual, said in-ear device having a sound bore with an environment opening and an ear opening outside and inside said ear canal respectively, said environment opening being adapted to be removably engaged by a remote device such as a sound measurement device, a filter device, an amplifier device, a plug device and the like, said apparatus comprising a sound measurement device being said remote device and having a probe microphone and reference microphone isolated from each other and connected to a data processing unit having a control box and a reference sound source, both connected to a computer unit, said probe and reference microphones being adapted for measuring a sound pressure level inside said ear canal of said individual and a sound pressure level from said environment in close proximity of said in-ear device respectively, said sound pressure levels corresponding to a known noise signal created by said reference sound source at an inlet to the individual'"'"'s ear in a close proximity of said in-ear device, said data processing unit being adapted for recording and processing said sound pressure levels read by both said probe and reference microphones corresponding to said known noise signal to provide a corresponding calculated value of a sound level difference provided by said in-ear device.

2. An apparatus as defined in claim 1, wherein said in-ear device being expandable and further having an injection channel with an opened end outside said ear canal and a closed end inside said in-ear device adapted to receive a settable compound material allowing for said in-ear device to properly assume said ear canal of said individual, said apparatus being adapted for continuously monitoring said calculated value of said sound level difference while said compound material being simultaneously slowly injected into said expandable in-ear device via said injection channel, said data processing unit being adapted for advising to stop injecting said compound material into said expandable in-ear device upon obtaining a calculated value of a sound pressure level difference of said in-ear device achieving first occurring of being either substantially equal to a predetermined sound pressure level difference or a substantially time stable sound level difference conditions.

3. An apparatus as defined in claim 2, wherein either said predetermined sound pressure level difference or said time stable sound level difference being determined over a pre-selected frequency range.

4. An apparatus as defined in claim 1, further comprising a second measurement device adapted to engage an environment opening of a sound bore of a second in-ear device inserted into a second ear canal of said individual, said second measurement device being simultaneously connected to said control box of said data processing unit for the same to simultaneously provide a second corresponding calculated value of a sound level difference provided by said second in-ear device.

5. An apparatus as defined in claim 1, wherein said computer unit including a display member for displaying said calculated value of said sound level difference provided by said in-ear device.

6. An apparatus as defined in claim 3, wherein said computer unit including a display member for displaying said calculated value of said sound level difference provided by respective of said in-ear devices.

7. An apparatus as defined in claim 4, wherein said computer unit includes a display member for continuously displaying said calculated value of said sound level difference provided by said in-ear device.

8. An apparatus as defined in claim 5, wherein said control box being adapted for filtering and sequentially sending said sound pressure levels read by said probe and reference microphones of said in-ear device to said computer unit.

9. An apparatus as defined in claim 6, wherein said control box being adapted for filtering said sound pressure levels read by said probe and reference microphones of both of said in-ear devices and having a multiplexer for sequentially sending the same to said computer unit.

10. An apparatus as defined in claim 1, wherein said in-ear device having a second sound bore with an environment opening and an ear opening outside and inside said ear canal respectively, said environment opening of said second sound bore being adapted to be removably engaged by a second remote device, said second remote device being either an amplifier device or filter device adapted for a pre-selected frequency window, said second remote device engaging said environment opening of said second sound bore during measuring said sound pressure levels by said probe and reference microphones.

11. An apparatus as defined in claim 1, wherein said computer unit containing pre-determined correction factors and a transfer coefficient, said apparatus determining an estimated insertion loss value provided by said in-ear device from said calculated value of said sound level difference and said predetermined correction factors and transfer coefficient.

13. A method as defined in claim 12, further comprising, after step b), the step of:

b1) performing calibration of said data processing unit to check proper connection of said control box to said computer unit.

14. A method as defined in claim 13, wherein said in-ear device being expandable and further having an injection channel with an opened end outside said ear canal adapted to be removably engaged by a settable compound material injection device and a closed end inside said in-ear device adapted to receive said settable compound material allowing for said in-ear device to properly assume said ear canal of said individual, said method further comprising, after steps f) and i) respectively, the steps of:

f1) starting a slow injection of said compound material into said expandable in-ear device via said injection channel;

i1) repeating steps f) through i) to continuously monitor said calculated value of said sound level while simultaneously keeping on injecting said compound material;

i2) stopping said injection upon obtaining a calculated value of a sound pressure level difference of said in-ear device achieving first occurring of being either substantially equal to a predetermined sound pressure level difference or a substantially time stable sound level difference conditions.

15. A method as defined in claim 14, wherein either said predetermined sound pressure level difference or said time stable sound level difference being determined over a pre-selected frequency range, said method further comprising, after step c), the step of:

c1) performing selection of said pre-selected frequency range for obtaining a corresponding calculated value of a sound pressure level difference.

16. A method as defined in claim 15, said computer unit including a display member, said method further comprising, between steps i) and i1), the step of:

i′

) displaying said calculated value of said sound level difference provided by said in-ear device on said display member.

17. A method as defined in claim 16, further comprising, after step l), the step of:

l1) waiting for said settable compound material to properly set before performing any following step.

18. A method as defined in claim 12, wherein said in-ear device having a second sound bore with an environment opening and an ear opening outside and inside said ear canal respectively, said environment opening of said second sound bore being adapted to be removably engaged by a second remote device, said method further comprising, after step a), the step of:

a1) engaging said second remote device being either an amplifier device or a filter device adapted for a pre-selected frequency window to said environment opening of said second sound bore.

19. A method as defined in claim 12, wherein steps a) to i) are simultaneously performed for a second in-ear device inserted into a second ear canal of said individual and using a corresponding second sound measurement device adapted to engage an environment opening of a sound bore of said second in-ear device.

20. A method as defined in claim 12, wherein said computer unit containing pre-determined correction factors and a transfer coefficient, said method further comprising, after step i), the step of:

i′

) estimating an insertion loss value provided by said in-ear device from said calculated value of said sound level difference and said pre-determined correction factors and transfer coefficient.

12. A method for determining in-situ the acoustic seal provided by an in-ear device inserted into an ear canal of an individual, said in-ear device having a sound bore with an environment opening and an ear opening outside and inside said ear canal respectively, said environment opening being adapted to be removably engaged by a remote device such as a sound measurement device, a filter device, an amplifier device, a plug device and the like, said method comprising the steps of:

a) providing said sound measurement device having a probe microphone and a reference microphone isolated from each other and a data processing unit having a control box and a reference sound source, both connected to a computer unit,

b) turning on said data processing unit;

c) connecting said measurement device to said data processing unit;

d) testing connection of said measurement device to said data processing unit by measuring a known noise signal from said reference sound source with said probe and reference microphones;

e) engaging said measurement device into said environment opening of said sound bore, said probe and reference microphones for measuring a sound pressure level inside said ear canal of said individual and a sound pressure level from said environment in close proximity of said in-ear device respectively;

f) sending a known noise signal from said reference sound source;

g) recording sound pressure levels read by both said probe and reference microphones corresponding to said known noise source signal;

h) processing said measured sound pressure levels;

i) obtaining a calculated value of a sound level difference provided by said in-ear device;

j) turning off said data processing unit;

k) disconnecting said measurement device from said data processing unit; and

l) disengaging said measurement device from said in-ear device.