Pressure equalization systems and methods

1. A headphone apparatus comprising:

a speaker having a diaphragm;

an earpiece comprising a chamber, the chamber having a passageway, wherein the chamber is configured to be at least partially bounded by the diaphragm and an ear of a user when the earpiece is worn by the user;

a valve in the earpiece configured to relieve acoustic pressure in the chamber; and

a valve control assembly configured to control the valve based on sensed acoustic pressure in the chamber, wherein the valve is configured to open to relieve the acoustic pressure in the chamber when the acoustic pressure in the chamber exceeds a threshold.

2. The apparatus of claim 1 , wherein the valve is a two-position valve having an at-rest state and an actuated state, wherein in the at-rest state, the valve is configured to seal the passageway, and wherein in the actuated state, the valve is configured to enable passage of air through the passageway.

3. The apparatus of claim 1 , wherein the valve control assembly is configured to control a size of an opening to the chamber made by the valve by an amount proportional to the sensed acoustic pressure in the chamber.

4. The apparatus of claim 1 , wherein the passageway is in an inner earpiece barrier that separates the chamber from a second chamber of the earpiece.

5. The apparatus of claim 4 , wherein a housing of the earpiece comprises an equalization port between the second chamber and an ambient environment, wherein, when open, the valve is configured to enable passage of air between the chamber and the second chamber, and wherein the equalization port is configured to enable the air to flow between the second chamber and the ambient environment.

6. The apparatus of claim 1 , wherein the valve control assembly is configured to close the valve when the sensed acoustic pressure is below the threshold.

7. The apparatus of claim 1 , wherein the valve control assembly is configured to detect an over-pressure disturbance when the sensed acoustic pressure in the chamber exceeds the threshold.

8. The apparatus of claim 6 , further comprising a sensor configured to provide, to the valve control assembly, a first signal corresponding to the sensed acoustic pressure in the chamber.

9. The apparatus of claim 8 , wherein the valve control assembly further comprises a valve actuator associated with the valve, and wherein the valve control assembly is configured to actuate the valve actuator based on the first signal.

10. The apparatus of claim 9 , wherein the valve actuator comprises a solenoid, a piezoelectric member, a shape memory actuator, or a combination thereof.

11. The apparatus of claim 9 , wherein the valve control assembly comprises circuitry coupled to the sensor and coupled to the valve actuator, the circuitry configured to receive the first signal, wherein the circuitry comprises a comparator configured to output a first control signal when the sensed acoustic pressure in the chamber exceeds the threshold and a second control signal when the sensed acoustic pressure in the chamber does not exceed the threshold.

12. The apparatus of claim 11 , wherein the valve actuator is an electrically driven actuator, wherein the valve control assembly is configured to energize the electrically driven actuator when the comparator outputs the first control signal, and wherein the valve control assembly is configured to not energize the electrically driven actuator when the comparator outputs the second control signal.

13. The apparatus of claim 11 , wherein the circuitry further comprises a rectifier and a low pass filter, the rectifier coupled to the sensor and coupled to the low pass filter, and the low pass filter coupled to the comparator, and wherein the rectifier is configured to receive the first signal.

14. The apparatus of claim 11 , wherein the circuitry further comprises an envelope follower comprising a full-wave peak detector, the full-wave peak detector having an attack time and a decay time, wherein the decay time is longer than the attack time.

15. A method, comprising:

at an earpiece that comprises a chamber and a valve associated with a passageway, the valve located within the earpiece and the chamber configured to be at least partially bounded by a diaphragm of a speaker located within the earpiece and by an ear of a user when worn by the user, performing:

sensing acoustic pressure within the chamber; and

regulating acoustic pressure within the chamber via the valve by controlling passage of a fluid through the passageway based on the acoustic pressure, wherein the valve opens to relieve the acoustic pressure in the chamber in response to the acoustic pressure in the chamber exceeding a threshold.

16. The method of claim 15 , wherein regulating the acoustic pressure comprises controlling a size of an opening to the chamber made by the valve by an amount proportional to the acoustic pressure.

17. The method of claim 15 , wherein the passageway is through a body of the earpiece that separates the chamber from an ambient environment.

18. The method of claim 15 , wherein the passageway is through an inner earpiece barrier that separates the chamber from a second chamber bound by a body of the earpiece and the inner earpiece barrier.

19. The method of claim 15 , wherein regulating the acoustic pressure within the passage comprises closing the passageway by closing the valve in response to determining that the acoustic pressure is less than the threshold.

20. The method of claim 15 , wherein the threshold is indicative of an over-pressure disturbance.

21. The method of claim 15 , further comprising determining whether the acoustic pressure exceeds the threshold by receiving a first signal from a sensor disposed within the earpiece, processing the first signal, and comparing the processed first signal to a signal corresponding to the threshold.