Modifying a Pioneer SP-99D AC-3 processor with TOSLINK digital out
During the later years of Laserdisc in 1995, Pioneer started releasing Laserdiscs with AC-3 sound capability. This meant you could get 5.1 surround sound on newer movies, as long as your player supported it and you could feed the audio signal into a demodulator or processor. The big difference between processors and demodulators are the capabilities and how they output their signal to a receiver. Demodulators normally have an input for AC-3 via a coax connection and sometimes will have an input for TOSLINK(SPDIF) optical. From there, the demodulator processes the signals and outputs them via a single cable to a receiver whether that be coax or optical. Example of a demodulator - Pioneer RFD-1 Processors, however, would normally output their sound via 6 discrete cables. On receivers, these are sometimes referred to as Multi Channel In. The 6 channels are Front Left, Center, Front Right, Subwoofer, Surround Left and Surround Right. This is all we...