A vibrating screed comprising a screed member, a motor, and an exciter assembly configured to vibrate the screed member in response to receiving torque from the motor via a driveshaft. The exciter assembly includes a first eccentric mass fixed on the driveshaft and a second eccentric mass axially and rotationally moveable along the driveshaft between a first position and a second position in which the second eccentric mass is axially closer to the first eccentric mass than in the first position. The vibrating screed further comprises a mode selection member to switch the exciter assembly between a first, low vibration mode, in which the second eccentric mass is in the first position, and a second, high vibration mode, in which the second eccentric mass is in the second position.