MULTI-FUNCTIONAL SPEAKER

摘要

PURPOSE: A multi-functional speaker is provided to reduce noises by reducing the influence of voice coil-induced current due to an outer magnetic field. CONSTITUTION: An upper plate(23) is on a magnet(22), and a yoke plate(21) is under the magnet. A movable coil is installed in a gap of a magnetic circuit constituted of the upper plate and the yoke plate. A fixed coil is installed outside the gap of the magnetic circuit and inside of a protector plate for protecting a speaker. The movable coil and the fixed coil are electrically connected via a conductor. The first signal flows through the movable coil and the second signal flows through the fixed coil to provide two impedances. The interval of the magnetic circuit gap is reduced to elevate sound pressure at 8 ohms, and only the movable coil is operated at 32 ohms to lower sound pressure.