SP-1B is a speaker born to work with the FDM-DUO and the FDM-DUOr. It can be used also if it is not powered, in this case the input is connected directly to the loudspeaker. It has three modes of operation :
flat mode, it produces the sound without equalization,
filtered mode, it applies a 300Hz ÷ 3kHz enhanced filter,
noise reduction mode, it allows to choose one of five levels of noise reduction.
Technical
Specifications
Power supply : 12÷15 Vdc (13.8Vdc typical).
THD for 10W RMS audio output on 4 ohms : < 1%.
THD for 15W RMS audio output on 4 ohms : typical 3%.