Control of a loudspeaker output
View Patent ↗A loudspeaker control system is disclosed. The loudspeaker control system includes a loudspeaker, a sensor for measuring a voltage and current and a processor. The processor is adapted to calculate an input-voltage-to-excursion transfer function over time from an admittance function, blocked electrical impedance and force factor, use the input-voltage-to-excursion transfer function over time to predict an excursion and use the excursion to control audio processing of the loudspeaker.
1. A method of controlling an output of a loudspeaker, comprising:
Measuring a coil voltage and a coil current over time;
Deriving an admittance function using the coil voltage and the coil current overtime;
Calculating an input-voltage-to-excursion transfer function over time from the admittance function, a blocked electrical impedance and a force factor;
Using the input-voltage-to-excursion transfer function over time to predict a coil excursion; and
Using the coil excursion to control audio processing of the loudspeaker.
2. The method as claimed in claim 1 , wherein the input-voltage-to-excursion transfer function h vx [k] is calculated by:
h
υ
x
[
k
]
=
1
ϕ
(
δ
[
k
]
-
R
e
y
[
k
]
)
*
h
int
[
k
]
,
(
19
)
where φ is the force factor, δ[k] is the delta function, y[k] is the admittance function, Re is the blocked electrical resistance and hint[k] is an integrator function.
3. The method as claimed in claim 1 , wherein the admittance function is obtained using adaptive filtering with the voltage and current signals as inputs.
4. The method as claimed in claim 1 , further comprising deriving the acoustical output transfer function from the voltage-to-excursion transfer function.
5. The method as claimed in claim 1 , wherein the force factor is a constant value.
6. A loudspeaker control system, comprising:
A loudspeaker;
A sensor for measuring a voltage and current; and
A processor,
Wherein the processor is adapted to:
Measure a coil voltage and a coil current over time;
Derive an admittance function using the coil voltage and the coil current overtime;
Calculate an input-voltage-to-excursion transfer function over time from the admittance function, a blocked electrical impedance and a force factor;
Use the input-voltage-to-excursion transfer function over time to predict a coil excursion; and
Use the coil excursion to control audio processing of the loudspeaker.
7. The system as claimed in claim 6 , wherein the processor is adapted to calculate the input-voltage-to-excursion transfer function h vx [k] based on:
h
vx
[
k
]
=
1
ϕ
(
δ
[
k
]
-
R
e
y
[
k
]
)
*
h
int
[
k
]
,
(
19
)
where φ is the force factor, δ[k] is the delta function, y[k] is the admittance function, Re is the blocked electrical resistance and hint[k] is an integrator function.
8. The system as claimed in claim 6 , wherein the processor is adapted to obtain the admittance function using adaptive filtering with the voltage and current signals as inputs.
9. The system as claimed in claim 6 , wherein the processor is adapted to derive the acoustical output transfer function from the voltage-to-excursion transfer function.
10. A non-transitory computer readable media comprising programming instructions which when executed by a processor performs an operation, the operation comprising:
Measuring a coil voltage and a coil current over time;
Deriving an admittance function using the coil voltage and the coil current over time;
Calculating an input-voltage-to-excursion transfer function over time from the admittance function, a blocked electrical impedance and a force factor;
Using the input-voltage-to-excursion transfer function over time to predict a coil excursion; and
Using the coil excursion to control audio processing of the loudspeaker.
11. The non-transitory computer readable media as claimed in claim 10 , wherein the input-voltage-to-excursion transfer function h vx [k] is calculated by:
h
vx
[
k
]
=
1
ϕ
(
δ
[
k
]
-
R
e
y
[
k
]
)
*
h
int
[
k
]
,
(
19
)
where φ is the force factor, δ[k] is the delta function, y[k] is the admittance function, Re is the blocked electrical resistance and hint[k] is an integrator function.
12. The non-transitory computer readable media as claimed in claim 10 , wherein the admittance function is obtained using adaptive filtering with the voltage and current signals as inputs.
13. The non-transitory computer readable media as claimed in claim 10 , further comprising deriving the acoustical output transfer function from the voltage-to-excursion transfer function.
14. The non-transitory computer readable media as claimed in claim 10 , wherein the force factor is a constant value.