Transducer assembly with acoustic mass

Abstract

A receiver assembly comprising a first and a second receiver housing and a spout. The second receiver housing is positioned over a first sound outlet port of the first receiver housing and the spout is positioned over a second outlet port of the second receiver housing. An acoustic duct is located between the first and second receiver housing acoustically connecting the first sound outlet port to the spout and is provided with an acoustic mass.

Claims

1-17. (canceled)

18. A transducer assembly, comprising: a receiver housing that houses a receiver; an opening through the housing through which sound exits the transducer assembly; a tube positioned at least partially within the opening, the tube acting as an acoustic impedance to filter the sound exiting the transducer assembly.

19. The transducer assembly of claim 18, further comprising a spout coupled to or forming part of the opening such that the tube extends through the opening and at least partially into the spout.

20. The transducer assembly of claim 18, further comprising a second housing that houses a transducer, wherein the opening is an acoustic duct that acoustically connects the receiver to a transducer in the second housing, the tube acting as a low-pass filter.

21. The transducer assembly of claim 18, wherein the tube extends at least partially across a diaphragm of the receiver.

22. The transducer assembly of claim 18, wherein an inner diameter of the tube is between 0.1 mm and 0.7 mm.

23. The transducer assembly of claim 18, wherein a length of the tube is between 0.5 mm and 5 mm.

24. The transducer assembly of claim 19, further comprising a second housing that houses a second receiver and has an outlet port, wherein an acoustic output of the receiver and the second receiver is merged into the spout.

25. The transducer assembly of claim 24, wherein the merged acoustic output is passed through a low pass filter corresponding to the tube.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0013] The invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0014] FIG. 1 is an exploded perspective view of an example of a receiver assembly according to aspects of the invention;

[0015] FIG. 2 is a perspective view of the assembly of FIG. 1 partially assembled;

[0016] FIG. 3 is top view of the lower receiver of the receiver assembly of FIG. 1;

[0017] FIG. 4 is a cross-section view of the receiver assembly of FIG. 1.

[0018] FIG. 5 is a perspective view of an example of a four driver three way setup according to aspects of the invention.

DETAILED DESCRIPTION

[0019] An example of an embodiment of a receiver assembly 1 according to the invention is shown in FIG. 1. A method for assembling the receiver assembly 1 comprises providing a first receiver housing 2 comprising a first sound outlet port 3 and a second receiver housing 4 comprising a second sound outlet port 5. Further provided are a spout 6, an acoustic duct 7 and an acoustic mass 8. The second receiver housing 4 is positioned over the first sound outlet port 3 of the first receiver housing 2, while the acoustic duct 7 is positioned between the first receiver housing 2 and the second receiver housing 4. The acoustic duct 7 is positioned such that it is located over the first sound outlet port 3 of the first receiver 2, acoustically connected with the first sound outlet port 3, and that end portion of the acoustic duct 7 is located near the second sound outlet port 5 of the second receiver housing 4. The acoustic mass 8 is positioned in the end portion of the acoustic duct 7 and a spout 6 is placed over the second sound outlet port 5 and the end portion of the acoustic duct 7. In this embodiment, the acoustic duct 7 is provided as a spacer member, i.e. a plate 9 having a certain thickness d, wherein a cut-out portion constitutes the acoustic duct 7 when it is positioned between the receiver housings 2, 4. FIG. 2 shows the assembled receiver housings 2, 4 and plate 9 in-between. Prior to positioning the acoustic duct 7 between the first receiver housing 2 and the second receiver housing 4, the acoustic duct 7, in this embodiment the plate 9, is mounted to the second receiver housing 4 such that the end portion of the acoustic duct 7 is located near the second sound outlet port 5 of the second receiver housing 4. This makes it easier to position the acoustic mass 8 in the end portion of the acoustic duct 7. Glue is applied to fixate the acoustic mass 8, filling any clefts left between the outer side of the acoustic mass 8 and the inner side of the acoustic duct 7. This also prevents any sound coming from the first sound outlet port 3 from circumventing the acoustic mass 8. Once glued, the spout 6 can be mounted over the second sound outlet port 5, in this embodiment shaped as a slit, and the outlet 13 of acoustic mass 8.

[0020] The according to the above obtained assembly 1 comprises first receiver housing 2 comprising a first sound outlet port 3, second receiver housing 4 comprising second sound outlet port 5 and a spout 6. In the assembly the second receiver housing 4 is positioned over the first sound outlet port 3, while the spout 6 is positioned over the second outlet port 5. Furthermore, the acoustic duct 7 is located between the first receiver housing 2 and the second receiver housing 4 and acoustically connects the first sound outlet port 3 to the spout 6. The acoustic mass 8 is positioned in the end portion of the acoustic duct 7 close to the spout 6. In this embodiment, the acoustic mass 8 comprises a tube in cross-section having an inner contour of circular shape. However, other cross-sectional shapes as square or hexagonal shapes are also possible. The outer diameter of the tube corresponds to the inner diameter of the end portion of the acoustic duct 7. The choice for the dimensions of the tube, length and inner diameter, depends on the desired corner frequency. Especially the inner diameter is set for tuning the corner frequency, e.g. an inner diameter of 0.1 mm results in a corner frequency 100 Hz (subwoofer), while 0.2 mm results in a corner frequency 1 kHz. The inner diameter is usually selected from 0.1 to 0.7 mm. The length can be chosen anywhere between 0.5 and 5 mm.

[0021] FIG. 3 shows the first sound outlet port 3, in this embodiment a circular shaped hole in receiver housing 2, acoustically connected to a chamber 10 of the acoustic duct 7. The chamber 10 preferably has a diameter larger than the diameter of the first sound outlet port 3. The acoustic duct 7 further comprises a passage 11 that runs from the chamber 10 to the side of the receiver assembly 1 where the spout 6 is to be mounted; accordingly when the spout 6 is mounted the passage 11 runs towards the spout 6. At the end of passage 11 running towards the spout 6 a recess 12 is left out, which aims to prevent glue from running into the tube 8 when being fixated in the passage 11. In another embodiment, it may suffice to have the diameter of the passage 11 expand at the edge of plate 9.

[0022] As best seen in FIG. 3 the acoustic duct is provided as cut-out portion in plate 9, wherein the cut-out portion constitutes the chamber 10, the passage 11 and recess 12. In another embodiment, the acoustic duct may be provided in the outer surface of the first or second receiver housing 2, 4: e.g. as a cut-out or grooved portion. In yet another embodiment, corresponding cut-out portions may be provided in the surface of both receiver housings which when assembled constitute the acoustic duct.

[0023] Plate 9 operates as a spacer member, providing a predetermined distance between the receiver housings 2, 4. The distance there between corresponds to the thickness of the plate. The thickness can be chosen such as to accommodate the acoustic mass, in this embodiment the outer diameter of tube 8. This allows the use of off-the-shelf receivers without the necessity of adapting the surface of the receiver housings or other additional measures to be able to position the acoustic mass between the receiver housings. Furthermore, the plate can be provided with means for attaching the receiver assembly to the inside of the casing of an earphone or hearing aid, thus functioning as a bracket member.

[0024] In the receiver assembly 1, the first receiver housing 2 preferably comprises a woofer transducer assembly and the second receiver housing 4 preferably comprises a mid-range transducer assembly or a tweeter transducer assembly. Thus, the receiver assembly operates as woofer-midrange or woofer-tweeter dual receiver assembly.

[0025] Referring to FIG. 4 there is shown a cross-section of the receiver assembly along line A-A′ as shown in FIG. 1. Shown are the transducer assemblies located respectively in the first and second receiver housings 2, 4 of this embodiment. The first receiver housing 2 houses a woofer transducer assembly 14 designed for producing sounds in the bass region of the audio spectrum. The woofer transducer assembly 14 comprises a motor assembly 15 driving a diaphragm 16 through a driving pin 17. The motor assembly 15 comprises a coil wire 18 wound around a bobbin 19, an armature 20 of U-shaped type and a magnet assembly 21. The magnet assembly comprises a magnet housing 22 and a pair of magnets 23a, 23b. The first receiver housing is made up of a case 24 and a cover 25. The case 24 is provided with connectors 26 for connecting a source of electric signals, representing e.g. audio signals for playback, to the transducer assembly 14.

[0026] The second receiver housing 4 houses a tweeter transducer assembly 34 designed for producing sounds in the upper region of the audio spectrum. The tweeter transducer assembly 34 comprises a motor assembly 35 driving a diaphragm 36 through a driving pin 37. The motor assembly 35 comprises a coil wire 38 wound around a bobbin 39, an armature 40 of the E-shaped type and a magnet assembly 41. The magnet assembly comprises a magnet housing 42 and a pair of magnets 43a, 43b. The second receiver housing 4 is made up of a case 44 and a cover 45. The case 44 is provided with connectors 46 for connecting a source of electric signals, representing e.g. audio signals for playback, to the transducer assembly 34.

[0027] The transducer assemblies operate as follows. Electric audio signals are transferred to each motor assembly 15, 35. Current running through the coils 18, 38 cause movement of the respective armatures 20, 40 which by means of the driving pins 17, 37 drive their respective diaphragms 16, 36. The induced vibrations of the diaphragms 16, 36 are transferred to the air located above the diaphragms. The vibrating air in the receiver housing constitute the sound waves produced by the receivers.

[0028] As explained above, between the first and second receiver housing 2, 4 the plate 9 is positioned with chamber 10 acoustically connected to the first sound outlet port 3. The sound produced by the woofer transducer assembly 14 in the first receiver housing 2 passes through the acoustic duct 7 and through the tube 8. The tube 8 acts as acoustic impedance and thus operates as acoustic low pass filter with a predetermined corner frequency corresponding to the design and dimensions of the tube 8. The filtered sound of the woofer assembly is joined with the sound of the tweeter assembly within the spout 6 and can travel further through a single sound channel.

[0029] FIG. 5 shows a four driver three way setup having four drivers i.e. transducers producing three different frequency spectra. This receiver assembly has a dual woofer receiver assembly 101, a mid-range receiver 52 and a tweeter receiver 50. The tweeter receiver 50 has a separate spout 51. The mid-range receiver 52 has a sound outlet port 53. The dual woofer assembly 101 has a first woofer receiver 102 and a second woofer receiver 104. The sound outlet ports of both woofer receivers 102, 104 are both acoustically connected to an acoustic duct. A tube 108 is located in the acoustic duct 107. A plate or bracket 54 is positioned over the front of the dual woofer receiver assembly 101 and mid-range receiver. The plate 54 has a slit 55 for passing sound from the sound outlet port 53 of the mid-range receiver and a hole 56 through which tube 108 is placed. The inner diameter of hole 56 is adapted to the outer diameter of the tube 108 to provide n acoustically sealing fit. A spout 106 is positioned over the slit 55 and tube 108 extending through hole 56.

[0030] Each of these embodiments and obvious embodiments thereof is contemplated as falling within the spirit and scope of the invention.