Granted Patent B2

US 12,212,921 · App. 17/880,910 · Granted Jan 28, 2025

Inventor: Jan Kueller (Ilmenau, DE)

Assignee: FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.

H04R1/2853G10K11/04G10K11/18H04R1/10

Abstract

Claims (45)

1. An Apparatus for sound conversion,

wherein the apparatus comprises a sound channel and a sound transducer coupled to the sound channel,

wherein the apparatus comprises an acoustic low-pass filter arranged in the sound channel,

wherein the acoustic low-pass filter divides a volume of the sound channel occupied by the acoustic low-pass filter into a first partial volume and at least one second partial volume,

wherein the first partial volume and the at least one second partial volume are coupled via at least one slit,

wherein the at least one slit expands along the sound channel in a sound propagation direction;

wherein the first partial volume is completely surrounded by the at least one second partial volume,

wherein the at least one slit enables a reduction of an acoustic speed in a treble tone range due to thermoviscous losses in a filter sound channel thereby providing a low-pass effect, wherein the low-pass effect results from lower frequencies passing through the filter sound channel in an unfiltered manner since a boundary layer thickness is larger than the slits for lower frequencies.

2. The Apparatus according to claim 1 ,

wherein the apparatus comprises a micro-perforated plate arranged in the sound channel between the sound transducer and the acoustic low-pass filter.

3. The Apparatus according to claim 1 ,

wherein the at least one second partial volume is coupled to the sound transducer exclusively via the first partial volume.

4. The Apparatus according to claim 1 ,

wherein the first partial volume is concentrically surrounded by the at least one second partial volume.

5. The Apparatus according to claim 1 ,

wherein the first partial volume is an internal partial volume,

wherein the at least one second partial volume is at least an external partial volume.

6. The Apparatus according to claim 5 ,

wherein the internal partial volume and the at least one external partial volume is coupled via a plurality of slits,

wherein the plurality of slits is arranged symmetrically with respect to a rotation axis of the sound channel.

7. The Apparatus according to claim 2 ,

wherein the micro-perforated plate is tuned to the sound transducer.

8. The Apparatus according to claim 2 ,

wherein the micro-perforated plate is configured to damp an acoustic treble/mid tone range.

9. The Apparatus according to claim 2 ,

wherein the micro-perforated plate is configured to shift sound energy into a target frequency range.

10. The Apparatus according to claim 1 ,

wherein the sound channel is rotationally symmetrical.

11. The Apparatus according to claim 1 ,

wherein the sound channel is a first sound channel coupled to a first side of the sound transducer,

wherein the apparatus comprises a second sound channel coupled to a second side of the sound transducer, opposite to the first side.

12. The Apparatus according to claim 11 ,

wherein the second sound channel is cylindrical.

13. The Apparatus according to claim 1 ,

wherein the sound transducer is a loudspeaker or a microphone.

14. The Apparatus according to claim 1 ,

wherein the apparatus is an auditory canal phone, a smart headphone/earphone, a hearing aid, a loudspeaker, or a microphone.

15. The Apparatus according to claim 1 ,

wherein the sound transducer is an MEMS sound transducer.

16. The Apparatus for adjusting the acoustic impedance of a sound transducer,

wherein the apparatus for adjusting the acoustic impedance is configured to divide a volume occupied by the apparatus for adjusting the acoustic impedance into a first partial volume and at least one second partial volume,

wherein the first partial volume and the at least one second partial volume are coupled via at least one slit so that the apparatus for adjusting the acoustic impedance comprises a low-pass character,

wherein the at least one slit expands along a sound channel in sound propagation direction,

wherein the first partial volume is surrounded by the at least one second partial volume,

wherein the at least one slit enables a reduction of an acoustic speed in a treble tone range due to thermoviscous losses in a filter sound channel thereby providing a low-pass effect, wherein the low-pass effect results from lower frequencies passing through the filter sound channel in an unfiltered manner since a boundary layer thickness is larger than the slits for lower frequencies.

Assignments (1)

Priority Claims (1)

Continuity (2)

References Cited (37)