Method for the non-linear control of an input signal for a loudspeaker

Patent metadata

Field	Value
Publication number	US-11871203-B2
Application number	US-202117501328-A
Country	US
Kind code	B2
Filing date	Oct 14, 2021
Priority date	Oct 14, 2020
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

A method for controlling a loudspeaker having an electromechanical force transducer and a diaphragm by:Providing a non-linear electromechanical model configured to apply one or more desired conditions to a loudspeaker input digital audio signal, i.e. to an analogic input signal converted in a digital input signal;Providing an inverse non-linear electromechanical model of the transducer configured to receive a signal processed by the non-linear model and to linearize at least one mechanical and/or electrical and/or electromechanical non-linearity of the transducer;Converting the digital output signal of the electromechanical model into an analog signal for the transducer,So that the output signal comprises an input voltage signal for the transducer and at least the second non-linear model is a digital wave filter (hereinafter referred to as Wave Digital Filters, WDF) to provide a directly computable function in the discrete-time domain to get the input voltage signal for the transducer.

First claim

The invention claimed is:

1. A method of controlling a loudspeaker having an electromechanical force transducer and a diaphragm comprising the steps of:
providing a non-linear model (FT) configured to apply one or more desired conditions to a loudspeaker input digital audio signal;
providing an inverse non-linear electromechanical (FI) model of the force transducer configured to receive a signal processed by the non-linear model and to compensate, preferably linearize, at least one mechanical and/or electrical and/or electromechanical non-linearity of a transducer coil; and
converting the digital output signal of the electromechanical model into an analog signal for the force transducer,
wherein the output signal comprises a voltage signal representative of the displacement of the transducer to emit sounds by the action of the transducer on the diaphragm and at least said non-linear electromechanical inverse model is a digital wave filter (WDF) model to provide a directly computable function of the input signal for the transducer and,

the aforementioned non-linear electromechanical model includes parameters of the speaker belonging to an electrical domain, and to a mechanical domain, the electrical and mechanical domain being coupled through a first conversion factor based on a first current-controlled voltage generator and a second current-controlled voltage generator to relate an electromagnetic force applied to said moving mass with a counter-electromotive force generated in the coil by the movement of the mass.

2. Method according to claim 1 , wherein said inverse model is obtained starting from a direct electromechanical model comprising a nullor.

3. Method according to claim 1 , wherein the desired condition is at least one of the desired frequency response conditions and/or a force factor dependent on the desired excursion and/or a mechanical stiffness dependent on the desired excursion and/or an inductance depending on the desired excursion of the force transducer.

4. Method according to claim 1 , wherein the electromechanical model comprises at least one parameter of an acoustic domain, the acoustic domain being coupled to the electrical and mechanical domains via a second conversion factor which relates acoustic waves of pressure generated by the diaphragm with a force applied by the transducer to the diaphragm.

5. Method according to claim 4 , wherein the second conversion factor is based on a voltage-controlled voltage generator and a current-controlled current generator.

6. A method of controlling a loudspeaker having an electromechanical force transducer and a diaphragm comprising the steps of:
providing a non-linear model (FT) configured to apply one or more desired conditions to a loudspeaker input digital audio signal;
providing an inverse non-linear electromechanical (FI) model of the force transducer configured to receive a signal processed by the non-linear model and to compensate, preferably linearize, at least one mechanical and/or electrical and/or electromechanical non-linearity of a transducer coil;
converting the digital output signal of the electromechanical model into an analog signal for the force transduce wherein

said inverse model is obtained starting from a direct electromechanical model comprising a nullor and
wherein the output signal comprises a voltage signal representative of the displacement of the transducer to emit sounds by the action of the transducer on the diaphragm and at least said non-linear electromechanical inverse model is a digital wave filter (WDF) model to provide a directly computable function of the input signal for the transducer and,

wherein the aforementioned non-linear electromechanical model includes parameters of the speaker belonging to an electrical domain, and to a mechanical domain, the electrical and mechanical domain being coupled through a first conversion factor based on a first current-controlled voltage generator and a second current-controlled voltage generator to relate an electromagnetic force applied to said moving mass with a counter-electromotive force generated in the coil by the movement of the mass.

7. A method of controlling a loudspeaker having an electromechanical force transducer and a diaphragm comprising the steps of:
providing a non-linear model (FT) configured to apply one or more desired conditions to a loudspeaker input digital audio signal;
providing an inverse non-linear electromechanical (FI) model of the force transducer configured to receive a signal processed by the non-linear model and to compensate, preferably linearize, at least one mechanical and/or electrical and/or electromechanical non-linearity of a transducer coil; and
converting the digital output signal of the electromechanical model into an analog signal for the force transducer, wherein

the desired condition is at least one of the desired frequency response conditions and/or a force factor dependent on the desired excursion and/or a mechanical stiffness dependent on the desired excursion and/or an inductance depending on the desired excursion of the force transducer;
wherein the output signal comprises a voltage signal representative of the displacement of the transducer to emit sounds by the action of the transducer on the diaphragm and at least said non-linear electromechanical inverse model is a digital wave filter (WDF) model to provide a directly computable function of the input signal for the transducer and

wherein the aforementioned non-linear electromechanical model includes parameters of the speaker belonging to an electrical domain, and to a mechanical domain, the electrical and mechanical domain being coupled through a first conversion factor based on a first current-controlled voltage generator and a second current-controlled voltage generator to relate an electromagnetic force applied to said moving mass with a counter-electromotive force generated in the coil by the movement of the mass.

8. Method according to claim 6 , wherein the electromechanical model comprises at least one parameter of an acoustic domain, the acoustic domain being coupled to the electrical and mechanical domains via a second conversion factor which relates acoustic waves of pressure generated by the diaphragm with a force applied by the transducer to the diaphragm.

9. Method according to claim 7 , wherein the electromechanical model comprises at least one parameter of an acoustic domain, the acoustic domain being coupled to the electrical and mechanical domains via a second conversion factor which relates acoustic waves of pressure generated by the diaphragm with a force applied by the transducer to the diaphragm.

10. Method according to claim 8 , wherein the second conversion factor is based on a voltage-controlled voltage generator and a current-controlled current generator.

11. Method according to claim 9 , wherein the second conversion factor is based on a voltage-controlled voltage generator and a current-controlled current generator.

12. A method of controlling a loudspeaker having an electromechanical force transducer and a diaphragm comprising the steps of:
providing a non-linear model (FT) configured to apply one or more desired conditions to a loudspeaker input digital audio signal;
providing an inverse non-linear electromechanical (FI) model of the force transducer configured to receive a signal processed by the non-linear model and to compensate, preferably linearize, at least one mechanical and/or electrical and/or electromechanical non-linearity of a transducer coil; and
converting the digital output signal of the electromechanical model into an analog signal for the force transduc

Assignees

• Elettromedia S R L
• Milano Politecnico
• Elettromedia S P A

Inventors

• Bernardini Alberto
• Bianchi Lucio
• Pantaleone Pietro
• Sarti Augusto

Classifications

• H04R9/06 Primary

  Loudspeakers · CPC title

• H04R3/007 Primary

  Protection circuits for transducers · CPC title