Hello Erik,

On the back of the DSL100H there are three speaker sockets and a impedance switch, one socket is for 16ohms only the other two sockets can take either 2 x 16ohms speakers or 2 x 8 ohms speakers. If you are using 2 x 16 ohm speakers you would set the impedance switch to 8 ohms, if you are using 2 x 8ohms speakers you would set the impedance switch to 4 ohms. You cannot use 2 x 4ohms speakers with this amplifier.