Miniature loudspeaker module, method for enhancing frequency response thereof, and electronic device

Patent metadata

Field	Value
Publication number	US-2016286305-A1
Application number	US-201414397831-A
Country	US
Kind code	A1
Filing date	Jun 5, 2014
Priority date	Nov 19, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

The present invention discloses a miniature loudspeaker module, a method for enhancing frequency response of a miniature loudspeaker module, and an electronic device. The method comprises the steps of: additionally providing a passive driver in a cavity where an active driver of a miniature loudspeaker module is located, the passive driver and the active driver radiating together, wherein, after the passive driver is additionally provided in the miniature loudspeaker module, the amplitude of a vibrating diaphragm of the active driver shows a local dip on frequency bands below a resonant frequency point F 0 , and the lowest point of the local dip is corresponding to a frequency point Fb; and, perform, according to amplitude characteristics of the vibrating diaphragm of the active driver of the miniature loudspeaker module additionally provided with the passive driver, matching enhancement to an input signal of the active driver. In the technical solutions provided by the present invention, as the frequency response of the whole miniature loudspeaker module on low frequency bands below F0 is enhanced after a passive driver is additionally provided, and matching enhancement is further performed to signals according to the amplitude characteristics of the active driver, the frequency resource of the miniature loudspeaker module on the whole frequency band is enhanced greatly.

First claim

1 . A method for enhancing frequency response of a miniature loudspeaker module, wherein the method comprises the steps of:
additionally providing a passive driver in a cavity where an active driver of a miniature loudspeaker module is located, the passive driver and the active driver radiating together; wherein, after the passive driver is additionally provided in the miniature loudspeaker module, the amplitude of a vibrating diaphragm of the active driver shows a local dip on frequency bands below a resonant frequency point F 0 , and the lowest point of the local dip is corresponding to a frequency point Fb; and perform, according to amplitude characteristics of the vibrating diaphragm of the active driver of the miniature loudspeaker module additionally provided with the passive driver, matching enhancement to an input signal of the active driver.

2 . The method according to claim 1 , wherein,
the miniature loudspeaker module is of a front porting design, and the passive driver and the active driver radiate separately; or, the miniature loudspeaker module is of a front porting design, and the passive driver and the active driver share a front cavity and radiate together; or, the miniature loudspeaker module is of a side porting design, and the passive driver and the active driver share a front cavity.

3 . The method according to claim 1 , wherein the perform, according to the amplitude characteristics of the vibrating diaphragm of the active driver of the miniature loudspeaker module additionally provided with the passive driver, matching enhancement to an input signal of the active driver comprises:
filtering out signals below a first frequency point which is a frequency point below Fb, to filter out signals having an amplitude beyond an allowable range of the vibrating diaphragm of the active driver on frequency bands below Fb; performing band-pass filtering and enhancement to signals within a certain frequency band taking Fb as a central frequency point, to realize low-frequency descending and bass enhancement; performing notch filtering to signals within a certain frequency band taking F 0 as a central frequency point, to avoid too large amplitude of the vibrating diaphragm of the active driver near F 0 ; and performing high-pass filtering and enhancement to signals above a second frequency point higher than F 0 , and enhancing mid and high frequency response by using the characteristic of small amplitude of the vibrating diaphragm of the active driver on mid and high frequency bands.

4 . The method according to claim 1 , wherein the method further comprises the steps of:
adjusting Fb by changing the coefficient of stiffness of the passive driver; and/or, adjusting F 0 by changing the property of the vibrating diaphragm and the quality of voice coil of the active driver; and adjusting, according to the values of Fb and F 0 and the characteristics of both a power amplifier and the amplitude of the vibrating diaphragm, one or more of the following parameters of a filter during the matching enhancement: Q value, order, frequency band attenuation parameter and cutoff frequency.

5 . A miniature loudspeaker module, comprising a cavity and an active driver disposed in the cavity, wherein the miniature loudspeaker module further comprises a passive driver and a matching enhancement unit;
the passive driver is disposed in the cavity where the active driver is located, and the passive driver and the active driver radiate together; wherein, after the passive driver is additionally provided in the miniature loudspeaker module, the amplitude of a vibrating diaphragm of the active driver shows a local dip on frequency bands below a resonant frequency point F 0 , and the lowest point of the local dip is corresponding to a frequency point Fb; and the matching enhancement unit is configured to perform, according to amplitude characteristics of the vibrating diaphragm of the active driver of the miniature loudspeaker module additionally provided with the passive driver, matching enhancement to an input signal of the active driver.

6 . The miniature loudspeaker module according to claim 5 , wherein, the miniature loudspeaker module is of a front porting design, and the passive driver and the active driver radiate separately;
or, the miniature loudspeaker module is of a front porting design, and the passive driver and the active driver share a front cavity and radiate together; or, the miniature loudspeaker module is of a side porting design, and the passive driver and the active driver share a front cavity.

7 . The miniature loudspeaker module according to claim 5 , wherein the matching enhancement unit comprises:
a very-low-frequency filter unit, configured to filter out signals below a first frequency point which is a frequency point below Fb, to filter out signals having an amplitude beyond an allowable range of the vibrating diaphragm of the active driver on frequency bands below Fb; a low-frequency enhancement unit, configured to perform band-pass filtering and enhancement to signals within a certain frequency band taking Fb as a central frequency point, to realize low-frequency descending and bass enhancement; a low-frequency reduction unit, configured to perform notch filtering to signals within a certain frequency band taking F 0 as a central frequency point, to avoid too large amplitude of the vibrating diaphragm of the active driver near F 0 ; and a high-frequency enhancement unit, configured to perform high-pass filtering and enhancement to signals above a second frequency point higher than F 0 , and enhance mid and high frequency response by using the characteristic of small amplitude of the vibrating diaphragm of the active driver on mid and high frequency bands.

8 . The miniature loudspeaker module according to claim 5 , wherein,
Fb is adjusted by changing the coefficient of stiffness of the passive driver; and/or, F 0 is adjusted by changing the property of the vibrating diaphragm and the quality of voice coil of the active driver; and according to the values of Fb and F 0 and the characteristics of both a power amplifier of the system and the amplitude of the vibrating diaphragm, one or more of the following parameters of a filter is adjusted during the matching enhancement: Q value, order, frequency band attenuation parameter and cutoff frequency.

9 . An electronic device, wherein the electronic device comprises the miniature loudspeaker module according to claim 5 .

10 . The electronic device according to claim 9 , wherein the electronic device is a mobile phone, a tablet computer, a tablet television set or a notebook computer.

Assignees

• Goertek Inc
• Goertek Inc

Inventors

• Hou Kang

Classifications

• H04R1/2834 Primary

  for loudspeaker transducers · CPC title

• H04R3/04 Primary

  for correcting frequency response · CPC title

• H04R3/08

  of electromagnetic transducers · CPC title

• H04R29/001

  for loudspeakers (H04R29/007 takes precedence) · CPC title

• H04R3/007

  Protection circuits for transducers · CPC title