Control of Sound Pressure in Audible Spot using Parametric Speakers
* Presenting author
We have studied about forming audible spot using parametric speakers for playing an audible signal to particular person. In previous work, the method to form audible spot using two parametric speakers was proposed. In the method, different tones of ultrasonic signals which have different frequency sent by two parametric speakers are played at crossed point of each signal. However, it has the problem that formed audible area was not stable because frequency characteristics of each speaker were not considered. This paper describes the technique to form stably audible area. In this technique, sound pressure of each speaker is controlled considering frequency characteristics. The proposed method was evaluated by experiments. Forming circular audible spot which diameter is 110 mm and sound pressure level is over 60 dB was tried. Although audible area changed about 75% when sound pressure was uncontrolled, stably audible spot could be formed by the proposed method with the change less than 20%. As the result, it is confirmed the usability of the proposed method.