That would be for theaters. DTS, Dolby Digital and SDDS are digital sound formats and (while I'm not sure if this is how they still do it) at the time of the SE's they were delivered to the theater with the prints on CD's. The Dolby Digital mix was used for the laserdiscs.

That would actually be a very interesting thing to pick up - I don't have the money at the moment, but if someone else would be willing to get these, we might be able to figure out a way to get the files off of them and sync them to the SE, which would provide much higher fidelity (I believe) than the laserdisc audio could.