Which surround algorithm is better?

I know this is a controversial topic. I know that there are those that only would listen to two channel and never to music in multi-channel. This question is not for you. I understand both sides of the issue. I have found that my room, which is 17' wide at the front, and 25' deep from front to rear (and I sit half way back) cannot reproduce a full symphony-like sound from my two speakers. They are VSA VR-4JRs and I like them for most everything I listen to. I have been experimenting with different surround processes and have found that some of the recordings sound more like a full symphony with some of the processes and others do not. Right now I am limited to the algorithms from my receiver, an Onkyo 805. I prefer the well produced SACDs and DVD-As but most of my music is in CD form. I am lucky enough to listen to the St. Louis Symphony in the beautiful and acoustically astounding Powell Hall, so I have real comparisons. My question is directed to those who have experimented with various algorithms. Which ones in your systems have come closest to the real thing in your rooms when changing two channel CDs into multi-channel? Which processes and processors do you like, especially for full symphony orchestras? Thanks.
I never heard any that I liked in the digital domain, but I had a McCormack MAP 1 multi channel anlog preamp that has so called Ambience Retrieval Mode (ARM) which works like a charm. The Conrad JOhnson MET1 has the same feature.
I have never heard any surround algorithm that is universally applicable. Some are fairly benign (Anthem-Logic) and others are usefully tweakable (TriField) but, ultimately, every one is caught out by one recording or another. If I feel the need to synth the surround from a stereo source (and that is rare), I skip through the options and use what works best for that source.

I do agree that the genre that benefits most from surround is classical orchestral music. The good news is there is a very good selection of multi channel SACD recordings of the majority of the major orchestral classical compositions. So rather then messing with your CD's I would instead go to a website like this:


Pick your composer and genre, filter for SACD (say recording quality minimum of 8) and see what comes up. Always more fun investing in software than hardware in my opinion anyway.
The downfall of synthetic multichannel is trying to get those rear/surround channels. A center front channel can be very effectively derived from stereo material.
Three channels from two is reasonable, but five from two is wishful thinking. I have a Trinaural processor which does an excellent job. I also have the McCormack MAP-1 multichannel preamp which does an OK job.

There are just a few recordings that pull off the full multichannel trick with awesome effect. Judy Collins singing Amazing Grace may be the best
I like my Yamaha AVR's '7ch stereo' mode for 2ch material and use it all the time. I don't want to limit myself to only a SACD music collection which is quite limited.

I don't think of 2ch material as just two channels... but as material with centre and left and right information.
I get a very nice sound stage from two channels and vinyl front end so that is how I listen to music.

For movies I sometimes use synthesized multichannel. I think I like the DTS synth better than the Dolby on my prepro (T175HD). I don't think the other choices sound as good.

I suspect there is truth in the statement that it depends on the particular program in question.