Speaker displacement detection calibration method and speaker displacement detection apparatus
A magnetic angle sensor outputs a component Vs in a Y direction where a vibration system of a synthetic vector of a magnetic vector of a magnetic circuit of a speaker and a magnetic vector of a displacement detection magnet fixed on the vibration system and a component Vc in an X direction orthogonal to the Y direction. A test signal is applied to the speaker, and collection of (Vs, Vc) and a measurement of a Y-direction displacement of the vibration system by a displacement meter are performed. A conversion equation “z=a1×Vs+a2×Vc” for the first principle component is obtained by principle component analysis on collected (Vs, Vc), and a conversion equation “y=b1×z2+b2×z+b3” for conversion to a displacement y is obtained by polynomial regression on the Y-direction displacement y of the displacement detection magnet obtained from a measurement value of the displacement meter and z calculated from collected (Vs, Vc).
1. A displacement detection calibration method of a speaker for calibrating a conversion equation for converting, when the method determines that a component in a Y direction is Vs and a component in an X direction that is orthogonal to the Y direction is Vc of a synthetic vector obtained by synthesizing a magnetic vector of a magnetic circuit of the speaker and a magnetic vector of a magnet fixed on a vibration system of the speaker, Vs, Vc output from a sensor fixed on a non-vibration system of the speaker into a displacement of the vibration system, the displacement detection calibration method comprising:
collecting the Vs, Vc output from the sensor by applying a predetermined test signal to the speaker, and in addition, measuring a displacement in the Y direction of the vibration system;
calculating the conversion equation from Vs, Vc to a first principle component z by performing principle component analysis on a corrected Vs, Vc;
performing, when the method determines that a displacement in the Y direction of the magnet obtained from a measurement value of a displacement meter, polynomial regression on a relationship between the displacement in the Y direction of the magnet and the first principle component z calculated from the corrected Vs, Vc to calculate the conversion equation for converting the first principle component z to the displacement in the Y direction of the magnet; and
setting an equation equivalent to an equation obtained by assigning the conversion equation for converting the calculated Vs, Vc into the first principle component z to a conversion equation for converting the calculated first principle component z to the displacement in the Y direction of the magnet as the conversion equation for converting Vs, Vc output from the sensor into the displacement of the vibration system.
2. The displacement detection calibration method according to claim 1 , wherein:
the conversion equation for converting Vs, Vc to the first principle component z is represented as z=a1×Vs+a2×Vc as a value for obtaining a1 and a2 by the principle component analysis, and
the conversion equation for converting the first principle component z to the displacement in the Y direction of the magnet is represented as y=b1×z2+b2×z+b3 as a value for obtaining b1, b2, and b3 by the polynomial regression.
3. A displacement detection calibration method of a speaker for calibrating a conversion equation for converting, when the method determines that a component in a Y direction is Vs and a component in an X direction that is orthogonal to the Y direction is Vc of a synthetic vector obtained by synthesizing a magnetic vector of a magnetic circuit of the speaker and a magnetic vector of a magnet fixed on a vibration system of the speaker, Vs, Vc output from a sensor fixed on a non-vibration system of the speaker into a displacement of the vibration system, the displacement detection calibration method comprising:
collecting the Vs, Vc output by the sensor when a predetermined test signal is applied to the speaker;
calculating the conversion equation from Vs, Vc to a first principle component z by performing principle component analysis on the corrected Vs, Vc;
performing, when it is determined that a displacement in the Y direction of the magnet obtained when the test signal calculated using a model obtained by modeling the speaker is y, polynomial regression on a relationship between the displacement in the Y direction of the magnet and the first principle component z calculated from the corrected Vs, Vc so as to calculate the conversion equation for converting the first principle component z to the displacement in the Y direction of the magnet; and
setting an equation equivalent to an equation obtained by assigning the conversion equation for converting the calculated Vs, Vc into the first principle component z to the conversion equation for converting the calculated the first principle component z to the displacement in the Y direction of the magnet as the conversion equation for converting Vs, Vc output from the sensor into the displacement of the vibration system.
4. The displacement detection calibration method according to claim 3 , wherein:
the conversion equation for converting Vs, Vc to the first principle component z is represented as z=a1×Vs+a2×Vc as a value for obtaining a1 and a2 by the principle component analysis, and
the conversion equation for converting the first principle component z to the displacement y is represented as y=b1×z2+b2×z+b3 as a value for obtaining b1, b2, and b3 by the polynomial regression.
5. A displacement detection device of a speaker configured to detect a displacement of a vibration system of the speaker, the displacement detection device comprising:
a magnet fixed on the vibration system of the speaker;
a sensor fixed on a non-vibration system of the speaker, the sensor configured to output Vs, Vc, when the sensor determines that a component in a Y direction is Vs and a component in an X direction that is orthogonal to the Y direction is Vc of a synthetic vector obtained by synthesizing a magnetic vector of a magnetic circuit of the speaker and a magnetic vector of the magnet; and
a controller configured to calculate a displacement in a Y direction of the non-vibration system of the speaker, when the controller determines that a first principle component obtained by principle component analysis performed on Vs, Vc is z, in accordance with a conversion equation for converting the first principle component z into y that is a displacement in a Y direction of the magnet.
6. A speaker unit that includes the displacement detection device according to claim 5 and the speaker in an integrated manner.