Pressure equalization in earphones

Patent metadata

Field	Value
Publication number	US-9301040-B2
Application number	US-201414211556-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Mar 14, 2014
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A headphone includes an electro-acoustic transducer dividing an enclosed volume into a front volume and a rear volume, a first port in the housing coupling the front volume to an ear canal of a user, a second port in the housing coupling the front volume to space outside the ear, a third port in the housing coupling the rear volume to space outside the ear, and an ear tip configured to surround the first port and including a flap to seal the ear canal from space outside the ear. The second port has a diameter and a length that provide an acoustic mass with an acoustic impedance with a high reactive component and a low resistive component, reducing the occlusion effect that otherwise results from sealing the ear.

First claim

What is claimed is:

1. A headphone comprising:
a housing defining an enclosed volume;
an electro-acoustic transducer dividing the enclosed volume into a front volume and a rear volume;
a first port in the housing arranged to couple the front volume to an ear canal of a user when the headphone is worn;
a second port in the housing arranged to couple the front volume to space outside the ear of the user when the headphone is worn;
a third port in the housing arranged to couple the rear volume to space outside the ear of the user when the headphone is worn; and
an ear tip configured to surround the first port and including a flap to seal the ear canal from space outside the ear when the headphone is worn, the housing comprising an extended tab for retaining the ear tip;
wherein
the second port has a diameter and a length that provide an acoustic mass with an acoustic impedance with a high reactive component and a low resistive component, and
an entrance to the first port is positioned next to a first side of the extended tab and an entrance to the second port is positioned next to a second side of the extended tab, such that the electro-acoustic transducer is approximately symmetrically loaded.

2. The headphone of claim 1 , wherein the second port has a diameter and a length that provide the second port with a low acoustic impedance at low frequencies and a high acoustic impedance at high frequencies.

3. The headphone of claim 1 , wherein the ear tip includes a void positioned to surround the second port exit, the ear tip protecting the second port exit from blockage.

4. The headphone of claim 3 , wherein the void does not impart additional acoustic impedance to the second port.

5. The headphone of claim 3 , wherein the ear tip is formed from materials having at least two different hardnesses, the portion of the ear tip defining the void being of a greater hardness than the portion of the ear tip forming the seal.

6. The headphone of claim 1 , wherein:
the transducer includes a diaphragm that is generally characterized by a first plane, is radially symmetric along a first axis perpendicular to the plane, and is bounded by an outer edge;
the first port extends from an entrance into the front volume near the outer edge of the transducer; and
the second port extends from an entrance into the front volume, the second port entrance being located along a line connecting the first axis to the first port entrance.

7. The headphone of claim 6 , wherein the second port entrance is located facing the diaphragm, between the first port and the first axis.

8. The headphone of claim 1 , wherein the first port has a lower characteristic acoustic impedance than the second port.

9. The headphone of claim 8 , wherein the second port has a characteristic acoustic impedance of at least 6.8×10 6 kg/m 4 at 20 Hz and at least 3.1×10 7 kg/m 4 at 3 kHz.

10. The headphone of claim 9 , wherein the third port has a characteristic acoustic impedance of at least 8.0×10 6 kg/m 4 at 20 Hz and at least 3.1×10 8 kg/m 4 at 3 kHz.

11. The headphone of claim 1 , wherein the second port has a characteristic acoustic impedance of at least 6.8×10 6 kg/m 4 at 20 Hz and at least 3.1×10 7 kg/m 4 at 3 kHz.

12. The headphone of claim 1 , further comprising a fourth port in the housing arranged to couple the front volume to space outside the ear of a user when the headphone is worn, the fourth port has a diameter and a length that provide the fourth port with a high acoustic impedance with a large resistive component and a low reactive component.

13. The headphone of claim 12 , wherein the fourth port has a characteristic acoustic impedance of at least 2.0×10 7 kg/m 4 at 3 kHz.

14. A headphone comprising:
a housing defining an enclosed volume;
an electro-acoustic transducer dividing the enclosed volume into a front volume and a rear volume;
a first port in the housing arranged to couple the front volume to an ear canal of a user when the headphone is worn;
a second port in the housing arranged to couple the front volume to space outside the ear of the user with a characteristic acoustic impedance of at least 6.8×10 6 kg/m 4 at 20 Hz and at least 3.1×10 7 kg/m 4 at 3 kHz when the headphone is worn;
a third port in the housing arranged to couple the rear volume to space outside the ear of the user with a characteristic acoustic impedance of at least 8.0×10 6 kg/m 4 at 20 Hz and at least 3.1×10 8 kg/m 4 at 3 kHz when the headphone is worn; and
an ear tip configured to surround the first port and form a seal between the housing and the ear canal when the headphone is worn, wherein:
the housing comprises an extended tab for retaining the ear tip, and
an entrance to the first port is positioned next to a first side of the extended tab and an entrance to the second port is positioned next to a second side of the extended tab, such that the electro-acoustic transducer is approximately symmetrically loaded.

15. The headphone of claim 14 , wherein the ear tip includes a void positioned to surround the second port exit, the ear tip protecting the second port exit from blockage.

16. The headphone of claim 15 , wherein the void does not impart additional acoustic impedance to the second port.

17. The headphone of claim 15 , wherein the ear tip is formed from materials having at least two different hardnesses, the portion of the ear tip defining the void being of a greater hardness than the portion of the ear tip forming the seal.

18. The headphone of claim 14 , wherein:
the transducer includes a diaphragm that is generally characterized by a first plane, is radially symmetric along a first axis perpendicular to the plane, and is bounded by an outer edge;
the first port extends from an entrance into the front volume near the outer edge of the transducer; and
the second port extends from an entrance into the front volume, the second port entrance being located along a line connecting the first axis to the first port entrance.

19. The headphone of claim 18 , wherein the second port entrance is located facing the diaphragm, between the first port and the first axis.

20. A headphone comprising:
an ear tip configured to seal the headphone to an ear canal of a user to form an enclosed volume including the ear canal and a front cavity of the headphone,
a housing comprising an extended tab for retaining the ear tip,
a front reactive port coupling the otherwise-sealed front cavity to space outside the headphone, to provide a consistent response across the audible spectrum, wherein the extended tab and ear tip cooperate to form a channel that surrounds the front reactive port, the channel protecting the front reactive port from blockage when the headphone is worn in the user's ear, and
a rear reactive port and a rear resistive port coupling a back cavity to space outside the headphone in parallel, to provide a high level of output for a given input signal level in combination with the seal.

21. The headphone of claim 20 , wherein the headphone is coupled to the ear canal through a characteristic acoustic impedance of less than 6.8×10 6 kg/m 4 at 20 Hz and less than 3.1×10 7 kg/m 4 at 3 kHz.

22. The headphone of claim 20 , wherein the front reactive port has a characteristic acoustic impedance of at least 6.8×10 6 kg/m 4 at 20 Hz and at least 3.1×10 7 kg/m 4 at 3 kHz.

23. The headphone of claim 20 , wherein the rear reactive port has a characteristic acoustic impedance

Assignees

• Bose Corp

Inventors

• Annunziato Kevin P
• Harlow Jason
• Shetye Mihir D
• Silvestri Ryan C

Classifications

• H04R2201/10

  Details of earpieces, attachments therefor, earphones or monophonic headphones covered by H04R1/10 but not provided for in any of its subgroups · CPC title

• H04R1/2826

  for loudspeaker transducers · CPC title

• H04R2460/11

  Aspects relating to vents, e.g. shape, orientation, acoustic properties in ear tips of hearing devices to prevent occlusion · CPC title

• H04R1/2884

  by means of the enclosure structure, i.e. strengthening or shape of the enclosure · CPC title

• H04R1/1075

  Mountings of transducers in earphones or headphones · CPC title