i have the 1.1 version that was around other sites downmixed to 1.0 not sure if it was from a laserdisc
The mono mix with the LFE track added to it (it’s called “2.1” rather than “1.1” because the mono mix is duplicated on the second channel) used the file that Zeropc ripped from the LaserDisc. Whoever made it resampled the LD mono mix from 44.1 kHz to 48 kHz, added the LFE track from the remastered DVD/Blu-ray 5.1 mix (which is already 48 kHz), and encoded it to DTS-HD Master Audio. In my opinion, the LFE channel does not blend well with the mono mix.
If anyone has the 2.1 mix but doesn’t want the LFE channel, you don’t want to downmix it, because that will just integrate the LFE in with the mono mix on a single channel. You want to open it in an audio editor and delete the LFE channel (which is channel 3). In Audacity you would do that by clicking the “X” to the left of the channel you want to delete:
You can also delete channel 2 if you want to, as it is merely a duplicate of channel 1, and deleting it will cut the file size in half. If you leave it as 2.0 and you have a 5.1 speaker setup, it will play in your front right and left speakers. If you delete channel 2, it will play in your center-channel speaker. If you only have a stereo speaker setup (2.0 or 2.1), it will play exactly the same regardless of whether it is 2.0 or 1.0.
Once you delete the unwanted channel(s), click File > Export Audio and save it as a WAV or FLAC (if you don’t want to introduce any loss).
In order to open a DTS file in Audacity you will need the FFmpeg Import/Export Library. Alternatively, you could convert it to WAV or FLAC before opening it in Audacity, for example, using Foobar2000 with a DTS decoder plugin. However, you’re only going to get the lossy core of the DTS file unless you decode it to WAV or FLAC using commercial software such as ArcSoft DTS Decoder.