PURPOSE: To induce a stable induction current to a diaphragm in accordance with a signal current supplied to an electromagnetic induction coil, to obtain highly efficient and sufficiently enough sound pressure output characteristics and to attain effective acoustic reproducing.
CONSTITUTION: This speaker is provided with a magnetic circuit part 11 for generating a DC magnetic field in a ring-like magnetic gap 19, a diaphragm 12 formed like a ring by a conductive material and supported in the gap 19 so as to be optionally oscillated and the 1st and 2nd electromagnetic induction coils 13, 14 arranged in the vicinity of the front side and rear side of the diaphragm 12 through the diaphragm 12. A signal current is supplied so that in- phase AC magnetic fields are generated around the coils 13, 14.
JPS5151928A | 1976-05-07 |