Abnormal sound eliminating system in record disc reproducing apparatus

An abnormal sound eliminating system for use in a record disc reproducing apparatus, said system comprising control signal generating means operated responsive to a multiplex signal of an angle-modulated wave signal and a direct wave signal picked up from a record disc on which the multiplex signals are recorded, said generating means producing a control signal having voltage which increases responsive to an increase of frequency of the carrier wave of the angle-modulated wave up to a predetermined frequency, low-pass filter means having a variable cut-off frequency, and means responsive to said control signal for controlling the cut-off frequency of said low-pass filter means, said cut-off frequency becoming higher as the voltage of the control signal increases and being lower than the frequency of the carrier wave while the frequency of the carrier wave is lower than the predetermined frequency, whereby said low-pass filter means responds to the multiplex signals picked up from the record disc and eliminates at least the carrier wave when it is reproduced from a record disc rotating at a speed which is lower than a specified rate.