OK I did the mix of the Eagle's "Peaceful Easy Feeling" a few ways - I used Audacity to split the stereo into a mono left and a mono right, then placed them into a 6-speaker 5.1 configuration just to the L & R channels.
Another mix was to take the mono L and R and put them into the 5.1 left, outer left, right and outer right, with the L/R also going to the subwoofer.
Final mix was to add to the mono L and R tracks a duplicate stereo track at -10dB intended for the center 5.1 channel - #3....
The end result....no significant difference, except that five speakers plus a subwoofer produces more midranges than 2 speakers....and when I listened to them in stereo earphones, no difference at all, showing that 5.1 stereo is not so different from 2-channel stereo. However, 5-channel discrete mono certainly has different placements from 2-channel stereo.
It's not possible to isolate each instrument from the melange that a mixed stereo track represents. Not by me, anyway, and I think AI will be a long way from doing that cleanly.
BTW, in order to use Audacity for AC3, you have to download the FFMPEG library dll, and then in Audacity's preferences for mixing, choose CUSTOM mix. Otherwise you get just stereo. This is well known, and any search on the Internet with the terms "Audacity AC3" will lead one to the exact details of how to and where to download.
Another mix was to take the mono L and R and put them into the 5.1 left, outer left, right and outer right, with the L/R also going to the subwoofer.
Final mix was to add to the mono L and R tracks a duplicate stereo track at -10dB intended for the center 5.1 channel - #3....
The end result....no significant difference, except that five speakers plus a subwoofer produces more midranges than 2 speakers....and when I listened to them in stereo earphones, no difference at all, showing that 5.1 stereo is not so different from 2-channel stereo. However, 5-channel discrete mono certainly has different placements from 2-channel stereo.
It's not possible to isolate each instrument from the melange that a mixed stereo track represents. Not by me, anyway, and I think AI will be a long way from doing that cleanly.
BTW, in order to use Audacity for AC3, you have to download the FFMPEG library dll, and then in Audacity's preferences for mixing, choose CUSTOM mix. Otherwise you get just stereo. This is well known, and any search on the Internet with the terms "Audacity AC3" will lead one to the exact details of how to and where to download.