Thank you so much. I'm impressed with the technical detail of your answer in a field which I am quite new to. More simply put, I need to read and study more and then, if I might, annoy you again later.
I'm trying to be overly philosophical but there are some really good people in the world. Unfortunately, on the net we rarely have a chance for a face-to-face meeting. I am grateful.
In conclusion, I gather that you are not impressed with the efforts described at http://www.surroundbyus.com
, your reasons being both specific and compelling:
1) Time investment not worth it
2) The effort is inherently futile, because of so much being pre-set in the studio
By way of IMHO criticism, I think your "I'll see to make some blind tests with regular MP3s converted to 5.1 using different stereo expander algorithms" approach is flawed. MP3 as you know is unlike FLAC which is lossless. MP3 compression is up to 10 times while FLAC might be 2 times or double. With MP3 too much is just tossed aside that cannot be gotten back ever again.
With LP's (long before your time I'm sure) we use to have dynamic range expanders because 33 1/3 rpm vinyl was compressed, but compressed in a lossless way to my understanding.
Dennis - IncurableGeek