| 摘要 |
PURPOSE:To eliminate the sound distortion caused by shift of cone paper due to gravity by adding the DC current, which flows to the voice coil of a speaker to restore the cone from shift, to the signal current from the amplifier which drives the speaker. CONSTITUTION:A DC current 1d is applied from an amplifier 6 to a speaker l through speaker terminals 7 and 8 together with the sound signal. The DC current Id flows to the voice coil of the speaker and is coupled to the magnetic field of a magnet to generate an electromagnetic force, thereby lifting the cone paper upward to cancel the gravity which pulls it down. Thus, the center position of oscillation of the voice coil of the cone paper coincides wit.h the center position of the magnet to prevent the sound distortion. The amplifier 6 incorporates a DC balance adjuster 9, and normally, a voltage Vd between speaker terminals 7 and 8 is set to 0 in the silent state by adjustment of the DC balance adjuster 9, but in this method, the balance adjuster 9 is adjusted from the outside by easy remodeling. |
