JPH067666Y2 - Sound field calibration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sound field calibration device for use in a home or vehicle-mounted acoustic device.

(Prior Art) Recently, graphic equalizers have been widely used in home-use or vehicle-mounted acoustic devices for the purpose of correcting the transmission frequency characteristic of a signal transmission system and calibrating the sound field. By equipping the audio equipment with the graphic equalizer, it becomes easy to match the acoustic characteristics to the listener's taste, but there is room for improvement in handling. That is, the graphic equalizer itself does not have a microphone for detecting the sound pressure level radiated from the speaker, and therefore the sound field characteristics when operating the graphic equalizer cannot be accurately known.

(Problems to be solved by the invention) Therefore, a device equipped with a spectrum analyzer for displaying the output level of the graphic equalizer for each divided band was developed. This spectrum analyzer has the effect of accurately grasping the sound field characteristics because the equalizing situation is clear at a glance, but the structure becomes complicated and, therefore, there is a problem in that it is expensive. For this reason, the sound field calibration is generally performed depending on the hearing of the proofreader.

The present invention has been made with this point in mind, and it is possible to easily and accurately calibrate the sound field without directly relying on the listener's ears and even in a general household that does not have an oscillator for obtaining the reference input. The purpose is to provide a device.

(Means for Solving Problems) As a means for solving the above problems, the present invention uses a sound field calibration device to record each frequency corresponding to the center frequency of each divided frequency band of the graphic equalizer at a constant level. The recording medium, a microphone for collecting the reproduced sound of the recording medium, an amplifier for amplifying the output signal of the microphone, and a level meter for visually displaying the magnitude of the output signal of the amplifier. It is configured as a thing. As a recording medium, magnetic tape is the most convenient for handling, but the recording medium is not limited to this and may be a record board or a compact disc.

(Operation) With such a configuration, the level meter can know the value of each frequency corresponding to the center frequency of each divided frequency band of the graphic equalizer reproduced from the recording medium. As long as the knob of the graphic equalizer is operated while visually observing, the sound field calibration can be performed easily and accurately.

(Embodiment) Next, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a microphone for collecting the reproduced sound of a recording medium (not shown). As described above, each frequency corresponding to the center frequency of each divided frequency band of the graphic equalizer is recorded on the recording medium at a constant level.
An output terminal 2 of the microphone 1 is connected to the input terminal 3 of the microphone amplifier 4.

The output side of the microphone amplifier 4 is connected to the level meter 6 via the meter drive amplifier 5. By this connection, the level meter 6 visually displays the output signal of the microphone 1 amplified by the microphone amplifier 4 and the meter drive amplifier 5. Therefore, it goes without saying that the microphone 1 and the microphone amplifier 4 must have flat frequency characteristics within the entire frequency band of the graphic equalizer.

The operation and usage will be explained. The recording medium is played and this is emitted by the speaker. If the recording medium is a magnetic tape, a tape recorder is used to reproduce the reference frequency sound. Then, the reference frequency sound is picked up by the microphone 1 arranged at a predetermined listening position, the output signal is amplified by the microphone amplifier 4 and the meter driving amplifier 5, and read by the level meter 6. This operation is repeated while reproducing the reference sound of each frequency, and the knob of the graphic equalizer corresponding to the frequency is adjusted so that the display of the level meter 6 at each frequency becomes constant. By these constant operations, the reproduction frequency characteristic of the audio device (audio device for calibrating the sound field) in the listening room and the listening position can be made substantially flat.

In this device, in order to avoid a slight discrepancy between the center frequency of the graphic equalizer and the recording frequency, or a sharp valley near the center frequency due to the characteristics of the reproduced sound field (room), set the recording frequency to several hertz to several tens of hertz. It is good to record so-called seismic sound by modulating with the sine wave of. Further, the microphone can be incorporated in a microphone amplifier, and further, the sound collecting and amplifying systems of these can be made into two systems and can be made into a stereo system. As the level meter, it is possible to use any one such as an optical display using an LED or a meter.

(Effect of the Invention) Since the present invention is configured and functions as described above, the sound field calibration by the graphic equalizer, which is conventionally performed depending on the sense of hearing, can be performed by, for example, one magnetic tape, a microphone, and an amplifier. There is an advantage that it can be performed easily and accurately with a simple device using only a level meter. Since the device is simple and can be obtained at low cost, the sound field can be easily calibrated by not only specialists but also general enthusiasts.

[Brief description of drawings]

The drawing is a circuit diagram of an embodiment of the present invention. 1 ... Microphone, 4 ... Microphone amplifier, 5 ...
… Meter drive amplifier, 6… Level meter

Claims (1)

[Scope of utility model registration request] 1. A recording medium in which each frequency corresponding to a center frequency of each divided frequency band of a graphic equalizer is recorded at a constant level, a microphone for collecting a reproduced sound of the recording medium, and an output signal of the microphone is amplified. And a level meter for visually displaying the magnitude of the output signal of the amplifier.