Patent ID: 7907737

Claim:
An acoustic apparatus comprising: a measuring signal generator configured to generate a unit pulse; an electric-acoustic transducer comprising a vibrator and configured to convert an electric signal to a sound by acoustically reproducing the unit pulse in a free sound field and to convert a characteristic vibration of the vibrator which is generated by an acoustic reproduction of the unit pulse to an electric characteristic vibration signal; a response signal analysis module configured to analyze the characteristic vibration signal in order to output a physical quality representing a characteristic vibration of the electric-acoustic transducer; a controller configured to set one of a first state in which the electric-acoustic transducer converts an electric signal to a sound and a second state in which the electric-acoustic transducer converts a sound to an electric signal; and a switch configured to connect the measuring signal generator to the electric-acoustic transducer in the first state and to connect the response signal analysis module to the electric-acoustic transducer in the second state, wherein the measuring signal generator comprises: a control signal generator configured to generate a control signal in order to control the characteristic vibration of the vibrator based on the physical quantity representing the characteristic vibration; and an adder configured to add the unit pulse and the control signal in order to output the measuring signal; the electric-acoustic transducer is configured to convert an electric signal to a sound by acoustically reproducing the measuring signal at a measurement object and to convert a sound to an electric response signal by collecting a reflection sound of the measuring signal which is acoustically reproduced at the measurement object; and the response signal analysis module is configured to output, based on the response signal, a physical quantity representing an acoustic characteristic of the measurement object.