Sound pressure monitor

• US 20070274531A1
• Filed: 05/24/2006
• Published: 11/29/2007
• Est. Priority Date: 05/24/2006
• Status: Abandoned Application

• Current Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Camp, William O.
• Application Number:
  US11/440,273
• Publication Number:
  US 20070274531A1
• Time in Patent Office: Days
• US Class Current: 381/74
• CPC Class Codes: H04R 1/1016 Earpieces of the intra-aural type
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 25/48 using constructional means for obtaining a desired frequency response H04R25/652 takes precedence
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

A method and apparatus for automatically adjusting the volume of a headset is described herein. The headset includes a speaker and a pressure transducer. The speaker projects audible signals into the ear canal, while the pressure transducer measures a sound pressure level in the ear canal. Based on the measured sound pressure level, a control system controls the volume of the audible sound projected from the speaker.

Claims

1. A closed-loop volume control system for an audio earphone comprising:

a speaker configured to project an audible signal into an ear canal;

a pressure transducer configured to measure a sound pressure level in the ear canal; and

a control system associated with the speaker and the pressure transducer, said control system configured to control a volume of the projected audible signal based on the measured sound pressure level.

2. The closed-loop volume control system of claim 1 further comprising an amplifier configured to drive the speaker responsive to an amplifier drive signal.

3. The closed-loop volume control system of claim 2 wherein the control system controls the volume of the projected audible signal by controlling a gain of the amplifier based on the measured sound pressure level.

4. The closed-loop volume control system of claim 2 wherein the control system controls the volume of the projected audible signal by controlling an amplitude of the amplifier drive signal input to the amplifier based on the measured sound pressure level.

5. The closed-loop volume control system of claim 2 wherein the amplifier comprises a variable gain amplifier.

6. The closed-loop volume control system of claim 1 wherein the control system is configured to reduce a volume of the projected audible signal when the measured sound pressure level exceeds a first threshold.

7. The closed-loop volume control system of claim 1 wherein the control system is configured to reduce a volume of the projected audible signal when the measured sound pressure level exceeds a first threshold for longer than a first time period.

8. The closed-loop volume control system of claim 7 wherein the control system is configured to increase the volume of the projected audible signal when the measured sound pressure level remains below a second threshold for longer than a second time period.

9. The closed-loop volume control system of claim 1 wherein the control system is configured to reduce a volume of the projected audible signal when the measured sound pressure level exceeds a first threshold for longer than a first time period or when the measured sound pressure level exceeds a second threshold for longer than a second time period.

10. The closed-loop volume control system of claim 1 wherein control system is further configured to isolate different frequency components of the measured sound pressure level to generate frequency-dependent sound pressure level measurements.

11. The closed-loop volume control system of claim 10 wherein the control system is further configured to equalize the projected audible signal based on the frequency-dependent sound pressure level measurements.

12. The closed-loop volume control system of claim 10 wherein the control system controls a volume of the projected audible signal by controlling an amplitude of one or more of the frequency components of the projected audible signal based on the frequency-dependent sound pressure level measurements.

13. The closed-loop volume control system of claim 1 wherein the control system is configured to control the volume by reducing an amplitude of a frequency component of the projected audible signal when the measured sound pressure level corresponding to the frequency component exceeds a threshold.

14. The closed-loop volume control system of claim 1 wherein the control system is co-located with the speaker and the pressure transducer in the audio earphone.

15. The closed-loop volume control system of claim 1 wherein the speaker and the pressure transducer are co-located in the audio earphone, and wherein the control system is located in a remote electronic device connected to the audio earphone via a wired connection.

16. The closed-loop volume control system of claim 1 wherein the speaker and the pressure transducer are co-located in the audio earphone, and wherein the control system is located in a remote electronic device connected to the audio earphone via a wireless connection.

17. The closed-loop volume control system of claim 1 wherein the control system is further configured to cancel noise present in the ear canal based on an inactivity sound pressure level measured by the pressure transducer when the speaker is inactive.

18. The closed-loop volume control system of claim 1 wherein the pressure transducer is acoustically isolated from the audible signal inside the audio earphone, and wherein the pressure transducer is acoustically coupled to the audible signal inside the ear canal.

19. A method of controlling sound pressure levels in an ear canal, the method comprising:

measuring a sound pressure level in the ear canal using a pressure transducer disposed in the ear canal; and

controlling a volume of an audible signal projected into the ear canal by a speaker based on the measured sound pressure level.

20. The method of claim 19 further comprising:

driving an amplifier with an amplifier drive signal; and

driving the speaker with a speaker drive signal output by the amplifier to project the audible signal from the speaker.

21. The method of claim 20 wherein controlling the volume comprises controlling an amplitude of the amplifier drive signal based on the measured sound pressure level.

22. The method of claim 20 wherein controlling the volume comprises controlling a gain of the amplifier.

23. The method of claim 19 wherein controlling the volume comprises reducing the volume of the projected audible signal when the measured sound pressure level exceeds a first threshold.

24. The method of claim 19 wherein controlling the volume comprises reducing the volume of the projected audible signal when the measured sound pressure level exceeds a first threshold for longer than a first time period.

25. The method of claim 24 wherein controlling the volume comprises increasing the volume of the projected audible signal when the measured sound pressure level remains below a second threshold for longer than a second time period.

26. The method of claim 19 wherein controlling the volume comprises reducing the volume of the projected audible signal when the measured sound pressure level exceeds a first threshold for longer than a first time period or when the measured sound pressure level exceeds a second threshold for longer than a second time period.

27. The method of claim 19 further comprising isolating different frequency components of the measured sound pressure level to generate frequency-dependent sound pressure level measurements.

28. The method of claim 27 wherein controlling the volume comprises controlling an amplitude of one or more frequency components of the projected audible signal based on the frequency-dependent sound pressure level measurements.

29. The method of claim 27 further comprising equalizing the projected audible signal based on the frequency-dependent sound pressure level measurements.

30. The method of claim 19 wherein controlling the volume comprises reducing an amplitude of a frequency component of the projected audible signal when the measured sound pressure level corresponding to the frequency component exceeds a threshold.

31. The method of claim 19 further comprising:

generating a noise cancelling signal based on an inactivity sound pressure level measured when the speaker is inactive; and

cancelling noise from the ear canal by projecting the noise cancelling signal into the ear canal via the speaker.

32. An audio earphone comprising:

a pressure transducer configured to measure a sound pressure level in an ear canal; and

a speaker configured to project an audible signal into the ear canal at a volume at least partially controlled based on the measured sound pressure level.

33. The audio earphone of claim 32 further comprising a controller operatively connected to the speaker and the pressure transducer, said controller configured to control the volume of the projected audible signal by controlling an amplitude of the projected audible signal based on the measured sound pressure level.

34. The audio earphone of claim 33 wherein the controller is configured to reduce the amplitude of the projected audible signal when the measured sound pressure level exceeds a first threshold.

35. The audio earphone of claim 33 wherein the controller is configured to reduce the amplitude of the projected audible signal when the measured sound pressure level exceeds a first threshold for longer than a first time period.

36. The audio earphone of claim 35 wherein the controller is configured to increase the amplitude of the projected audible signal when the measured sound pressure level remains below a second threshold for longer than a second time period.

37. The audio earphone of claim 33 wherein the controller is further configured to cancel noise present in the ear canal based on an inactivity sound pressure level measured when the speaker is inactive.

38. The audio earphone of claim 32 wherein the pressure transducer is acoustically isolated from the audible signal in the audio earphone, and wherein the pressure transducer is acoustically coupled to the audible signal in the ear canal.