Abstract: A signal conditioner is provided for the output of a digital sound source in a dual digital/analog motion picture theater sound system so that the digitally derived audio signal emulates the analog sound track signal. This allows the digital source to be easily integrated into the overall sound system, without displacing the existing analog sound track system. The theater sound playback mechanism is provided with the conditioned audio signal when the digital sound source is actuated, and receives the analog sound track signal at other times. The conditioning circuit includes an adjustable impedance to match the current from the digital sound source to the current from the analog sound track reader, a high frequency variable signal adjuster that is complimentary to a high frequency emphasis built into the theater playback system, and an optional subwoof output.