Filter system for hearing protection device for continuous noise exposure monitoring

1. A hearing protection device to be worn at either a primary position or a secondary position, comprising a hearing protection component and a noise measurement component, and an attachment mechanism to securely attach the noise measurement component to the hearing protection component, wherein

at the primary position the noise measurement component detects a protected noise exposure and at the secondary position it detects an unprotected exposure,

the noise measurement component comprises a microphone having a face, a compartment that encloses the microphone and at least one filter,

the filter comprises one or more pieces of polyester cloth snuggly fit to the face of the microphone, and

the filter minimizes resonance at a frequency of about 4.5 kHz without significantly attenuating other frequencies incident upon the face of the microphone.

2. The hearing protection device according to claim 1 , wherein the filter substantially eliminates resonance of said compartment.

3. The hearing protection device according to claim 1 , wherein the hearing protection component is an insert-type earplug.

4. The hearing protection device according to claim 3 , wherein the attachment mechanism comprises a screw-thread on a holder tip, and a channel through the middle of the plug which provides both a sound pathway for sampling the noise level and a mechanism for attaching the holder tip to the plug.

5. The hearing protection device according to claim 3 , wherein the compartment comprises a rear part that snap-fits to a front part.

6. The hearing protection device according to claim 5 , wherein the rear part securely holds the microphone in place via a silicone ring.

7. The hearing protection device according to claim 6 , wherein the rear part of the microphone holder assembly also provides a strain-relief to the microphone wire.

8. The hearing protection device according to claim 1 , wherein the filter comprises three pieces of polyester cloth.

9. The hearing protection device of claim 1 , wherein the microphone provides a flat response such that it captures all audible frequency components equally.

10. A hearing protection device to be worn at either a primary position or a secondary position, comprising a hearing protection component and a noise measurement component, wherein

at the primary position the noise measurement component detects a protected noise exposure and at the secondary position it detects an unprotected noise exposure,

the noise measurement component comprises a microphone, a microphone holder that encloses the microphone, at least one filter, and an attachment mechanism for removably attaching the noise measurement component to the hearing protection component;

the hearing protection component comprises an insert-type earplug;

the microphone holder comprises an acoustic duct having an exterior surface and an interior tube;

the attachment mechanism comprises screw threads on the exterior surface of the acoustic duct;

the interior tube of the acoustic duct serves as a channel through the middle of the earplug which provides a sound pathway for sampling noise exposure;

the filter reduces resonance incident upon the microphone;

the microphone holder further comprises a compartment for housing the microphone;

the compartment is located exterior to the earplug;

the microphone measures noise exposure via the interior tube; and

the filter comprises one or more pieces of polyester cloth.

11. The hearing protection device of claim 10 , wherein the noise measurement component further comprises a silicone ring that securely holds the microphone in place in the compartment.

12. The hearing protection device of claim 10 , wherein the microphone comprises a face and the filter is located within the interior tube adjacent to the microphone to reduce reflection of sound away from the face of the microphone.

13. The hearing protection device of claim 10 , wherein the microphone comprises a face and the filter is located within the microphone holder between the microphone and the interior tube to reduce reflection of sound away from the face of the microphone.

14. The hearing protection device of claim 10 , wherein the microphone comprises a face directed towards the interior tube in order to measure sound waves via the acoustic duct, and the filter covers the face of the microphone to reduce reflection of sound away from the face of the microphone.

15. The hearing protection device of claim 14 , wherein the filter comprises polyester cloth snuggly fit to the face of the microphone.

16. The hearing protection device of claim 14 , wherein the filter minimizes resonance at a frequency of about 4.5 kHz without significantly attenuating other frequencies.

17. The hearing protection device of claim 10 , wherein the filter minimizes resonance at a frequency of about 4.5 kHz without significantly attenuating other frequencies.

18. The hearing protection device of claim 17 , wherein the filter comprises three or more pieces of polyester cloth snuggly fit to the face of the microphone.

19. The hearing protection device of claim 10 , wherein the interior tube comprises an open end and a sealed end that is sealed by the microphone, the interior tube has a length of about 0.019 meters, and the filter decreases impendence of the sealed end of the interior tube.

20. The hearing protection device of claim 10 , wherein the microphone provides a flat response.