PURPOSE: To make possible the time axis compression and expansion of reproduction time by connecting an adapter provided with an equalizer for reproduction, pitch conversion circuit, etc. and a tape recorder.

CONSTITUTION: When a variable speech control adapter 26 is connected to a tape recorder 26 which performs recording and reproducing by the constant speed running of a tape 27, the reproduction signal through the preamplifier 37 of the recorder 26 goes through an equalizer 46 which corrects frequency characteristics according to the tape speed changing of the adapter 26, a pitch conversion circuit 47 which outputs pitch changes through controlling of the changing speed and direction of delay time, etc., whereby the time axis of the reproduction signal is compressed or expanded according to the redundancy of the audio signal according to the running speed of the tape 27 selected by a variable resistance 45, driving motor speed control circuit 48 of the recorder 26, thus the reproduction of the audio signal may be