| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic device for an electronic musical instrument in which reproducing characteristic, that are made suitable for the location of installation of the instrument and the environment, are automatically set. SOLUTION: An infrared ray emitting section 20 and an infrared ray receiving section 21 are arranged toward the back surface direction of an electronic musical instrument (for example, an electronic piano). When the electronic instrument is placed in the vicinity of a wall, infrared ray emitted from the section 20 is reflected by the wall and made incident on the section 21. When the quantity of light beams received at the section 21 exceeds a prescribed threshold value, a CPU 22 recognizes that the instrument is placed near the wall and transmits coefficients indicating a high pass filter characteristic to a frequency characteristic adjusting circuit 10a. Thus, the circuit 10a operates as a high pass filter and a DSP 10 outputs signals in which low frequency components are suppressed. A switching means may be provided, which is operated to match with the environment of the surroundings of the instrument so that the frequency characteristics of the music are varied in accordance with the state of the switching means. |
