Abstract: A separately packaged film sound editor mixer is disclosed which includes a plurality of low level audio signal input terminals adapted for connection to outputs from playback heads of a synchronizer. Magnetic tape preamplifiers are included for preamplification of the low level signals. The preamplified signals are connected through slide attenuators and muting switches to inputs of a first summing amplifier. The output from the first summing amplifier is connected to inputs of left and right channel summing amplifiers through a tone control circuit and a master attenuator of the slide type. A selector switch is included in the input for one of said magnetic tape preamplifiers whereby, in one switch position, an output from the synchronizer is supplied to the preamplifier, as mentioned above.