LaserDisc could carry analog audio or stereo PCM digital audio. (It could do Dolby Digital, then called AC3, but it doesn't sound like your player supports that.) For the PCM tracks and an analog output from the player, the player's DAC will play a not-insignificant role in the audio quality. The 990 can offer a number of processing modes when using stereo analog input. Pro Logic IIx and DTS NEO:6 will both allow you to produce surround sound from those two tracks. Upsample will also work, in which case the 990 will take the output of its ADC and resample to 192kHz/24-bit; no surround processing will occur in this case. There's also Bypass, which will leave the signal in the analog domain all the way through the 990 such that the 990 serves solely as a volume control. You can even use 5-Stereo or 7-Stereo if you like.