Bone conduction speaker and compound vibration device thereof
The present disclosure relates to a bone conduction speaker and its compound vibration device. The compound vibration device comprises a vibration conductive plate and a vibration board, the vibration conductive plate is set to be the first torus, where at least two first rods inside it converge to its center; the vibration board is set as the second torus, where at least two second rods inside it converge to its center. The vibration conductive plate is fixed with the vibration board; the first torus is fixed on a magnetic system, and the second torus comprises a fixed voice coil, which is driven by the magnetic system. The bone conduction speaker in the present disclosure and its compound vibration device adopt the fixed vibration conductive plate and vibration board, making the technique simpler with a lower cost; because the two adjustable parts in the compound vibration device can adjust both low frequency and high frequency area, the frequency response obtained is flatter and the sound is broader.
1. A bone conduction speaker, comprising a vibration device and a plurality of acoustic-electric transducers, wherein
the vibration device includes a vibration conductive plate and a vibration board, the vibration conductive plate is physically connected with the vibration board, vibrations generated by the vibration conductive plate and the vibration board have at least two resonance peaks, frequencies of the at least two resonance peaks being in a range of 80 Hz-18000 Hz, and sounds are generated by the vibrations transferred through a human bone; and
the plurality of acoustic-electric transducers includes a first acoustic-electric transducer having a first frequency response and a second acoustic-electric transducer having a second frequency response, the second frequency response being different from the first frequency response, wherein
the first acoustic-electric transducer is configured to detect an audio signal, and generate a first sub-band signal according to the audio signal; and
the second acoustic-electric transducer is configured to detect the audio signal, and generate a second sub-band signal according to the audio signal.
2. The bone conduction speaker according to claim 1 , wherein the first acoustic-electric transducer has a first frequency width, and the second acoustic-electric transducer has a second frequency width different from the first frequency width.
3. The bone conduction speaker of claim 2 , wherein the second frequency width is larger than the first frequency width, and a second center frequency of the second acoustic-electric transducer is higher than a first center frequency of the first acoustic-electric transducer.
4. The bone conduction speaker of claim 2 , wherein the first frequency response and the second frequency response intersect at a point which is near a half-power point of the first frequency response and a half-power point of the second frequency response.
5. The bone conduction speaker of claim 1 , further comprising:
a first sampling module connected to the first acoustic-electric transducer and configured to sample the first sub-band signal to generate a first sampled sub-band signal; and
a second sampling module connected to the second acoustic-electric transducer and configured to sample the second sub-band signal to generate a second sampled sub-band signal.
6. The bone conduction speaker of claim 5 , further comprising a feedback module configured to adjust at least one of the first acoustic-electric transducer or the second acoustic-electric transducer.
7. The bone conduction speaker of claim 6 , wherein the feedback module is configured to adjust the at least one of the first acoustic-electric transducer or the second acoustic-electric transducer according to at least one of the first sampled sub-band signal or the second sampled sub-band signal.
8. The bone conduction speaker of claim 6 , further comprising a processing module configured to process the first sampled sub-band signal and the second sampled sub-band signal to generate a first processed sub-band signal and a second processed sub-band signal, wherein the feedback module is configured to adjust the at least one of the first acoustic-electric transducer or the second acoustic-electric transducer according to the first processed sub-band signal or the second processed sub-band signal.
9. The bone conduction speaker of claim 1 , wherein the first acoustic-electric transducer includes a sound sensitive component and an acoustic channel component, the sound sensitive component being configured to generate an electric signal according to the audio signal.
10. The bone conduction speaker of claim 9 , wherein:
the acoustic channel component includes a second-order component; and
the sound sensitive component includes a multi-order bandpass diaphragm.
11. The bone conduction speaker of claim 1 , wherein the first acoustic-electric transducer includes a first-order bandpass filter or a multi-order bandpass filter.
12. The bone conduction speaker of claim 1 , wherein the bone conduction speaker includes at least one of:
no more than 10 first-order acoustic-electric transducers, wherein each first-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 20 kHz;
no more than 20 second-order acoustic-electric transducers, wherein each second-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 20 kHz;
no more than 30 third-order acoustic-electric transducers, wherein each third-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 20 kHz; or
no more than 40 fourth-order acoustic-electric transducers, wherein each fourth-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 20 kHz.
13. The bone conduction speaker of claim 1 , wherein the bone conduction speaker includes at least one of:
no more than 8 first-order acoustic-electric transducers, wherein each first-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 8 kHz;
no more than 13 second-order acoustic-electric transducers, wherein each second-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 8 kHz;
no more than 19 third-order acoustic-electric transducers, wherein each third-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 8 kHz; or
no more than 26 fourth-order acoustic-electric transducers, wherein each fourth-order acoustic-electric transducer corresponds to a frequency band whose width is no larger than 8 kHz.
14. The bone conduction speaker of claim 1 , wherein the first acoustic-electric transducer is a high-order wideband acoustic-electric transducer, and the second acoustic-electric transducer is a high-order narrow-band acoustic-electric transducer.
15. The bone conduction speaker of claim 14 , wherein the high-order wideband acoustic-electric transducer includes a plurality of underdamping sound sensitive components connected in parallel.
16. The bone conduction speaker of claim 15 , wherein the plurality of underdamping sound sensitive components include a first underdamping sound sensitive component having a fourth frequency response, a second underdamping sound sensitive component having a fifth frequency response, and a third underdamping sound sensitive component having a sixth frequency response, wherein:
a fifth center frequency of the second underdamping sound sensitive component is higher than a fourth center frequency of the first underdamping sound sensitive, and a sixth center frequency of the third underdamping sound sensitive component is higher than the fifth center frequency of the second underdamping sound sensitive, and
the fourth frequency response and the fifth frequency response intersect at a point which is near a half-power point of the fourth frequency response and a half-power point of the fifth frequency response.
17. The bone conduction speaker of claim 15 , wherein the plurality of underdamping sound sensitive components include a first underdamping sound sensitive component having a fourth frequency response, and a second underdamping sound sensitive component having a fifth frequency response, wherein:
the fourth frequency response and the fifth frequency response intersect at a point which is near a half-power point of the fourth frequency response and a half-power point of the fifth frequency response.
18. The bone conduction speaker of claim 14 , wherein the high-order narrow-band acoustic-electric transducer includes a plurality of underdamping sound sensitive components connected in series.
19. The bone conduction speaker according to claim 1 , wherein the vibration conductive plate includes a first torus and at least two first rods, the at least two first rods converging to a center of the first torus.
20. The bone conduction speaker according to claim 19 , wherein the vibration board includes a second torus and at least two second rods, the at least two second rods converging to a center of the second torus.