How to get multichannel sound from a CD?

I was at a friend's place recently and heard him play CDs through his new Linar multichannel amp, which has the ability to direct part of the stereo signal to the back speakers. The effect was surprisingly good: spatiality and power increased, without any apparent damage to sound quality (as long as the rears were not too loud!).

This got me thinking: Rather than wait forever for the major labels to start releasing good quality multichannel recordings in SACD or DVD-A, why not explore ways to get extra spatiality out of my existing large CD collection?

So I'm looking to find out what options exist for doing this. I'm just gathering info at this point, so any tips you have are of interest--a bonus would be your comments on how good it sounds, but just hearing about an option is good too.

Note that I do care very much about sound quality issues such as timbre, tonality, musicality. The best options for converting CD to multichannel will do minimal/no damage to essential sound quality, but will add spatiality.

So far I know about the following:
-The Linar amps, and maybe other multichannel amps, that just direct the sound to the back
-the Meridian 861 processor has a mode for this. Super expensive, supposed to be good.
-the McCormack universal player has a mode also. Stereophile seemed to like it a bit less than the Meridian for this purpose, but it costs a lot less.
-I think DTS has a processing mode in some receivers which can do this (I'm not much of a home theater guy, no receiver in my system, so I'm sure many of you will know more than I about this).

Any others you guys know about?
Check e-bay for one of these old units...I see them around every so often.

The Denon A/V receivers have this feature. They call it 5 channel stereo, and it processes a two channel stereo CD into 5 channels. I use this in my home theater room where critical listening is not a priority. It really fills the room with sound. I cannot comment on imaging, although I expect it's not as good as pure two channel
Best way to do it;

Trifield from a Meridian processor.

Dolby Prologic II depending on the pre/pro receiver is also very effective, just a little too live in the rears to be absolutely convincing. The music playback capacity of a prepro is the best way to seperate the good from the ugly.


5 channel stereo, like using a dull knife to cut tomatoes.

I don't listen in two channel unless I am forced too.
If you want some more advice just email me because the 2 channel guys are going to undoubtably chime in with their opinion on how lofi surround is. One day they will come around. That day has not come yet.
Thanks for responses so far...some interesting info.
BTW, it ain't the McCormack universal player that has this but, rather, the McCormack MAP-1 preamp. I use it mostly for TV audio but still play CDs in 2channel and SACDs/DVD-As in surround.

Most current A/V pre/pros and receivers have several options but the best seem to be the Logic7 (Lexicon, HK?, others?) and the Meridian TriField options.

What we are talking about is "matrix multichannel". With most any surround decoding system, Dolby, DTS, etc. signal that is out of phase between the two channels goes to the rear speakers. This is very damatic if you play a Test rrecording that has material recorded inphase, and out-of-phase for phasing check purposes.

The effectiveness when playing music depends entirely on how the particular recording was mixed. Some stereo recordings that were never intended for multichannel playback are, by accident, dramatic. Most don't work very well. There is no way to tell except to try them.
I am using 5 channel stereo using my Yamaha reciever's speaker
outputs as the input on my amplifiers. I personally auditioned
a couple of Dennon recievers at my local hi-fi store and was not that impressed with their sound in 5 channel stereo, plus the Yamaha had better options such as the speaker outputs are switchable (via switch on the back) between 4 and 8 ohms, 30 modes of DSP,higher power rating 100w/ch, and a better price.
All of these were deciding factors in purchasing this reciever. The sound I am getting from my setup it amazing. I hope this gives you some ideas.
Kr4: Right--it's the McCormack preamp, not the player. Thanks for the info on 'Logic7'--most of the reviewers seem to like it.

Eldartford: Do all of the surround algorithms (including Trifield, Logic7, etc.) work the way you describe, with out-of-phase signal going to the rear speakers? If not, perhaps some of them could be more consistently good with different recordings. I'm not really looking for something that is 'hit and miss' the way you describe matrix multichannel; if there aren't any solutions that work consistently well with a wide variety of discs, I may not want to go this route at all.
An old technology that still works surprisingly well is the Yamaha DSP system in several different options. Rather than try to extract out of phase information, it uses a vast array of measured locations to recreate the enviornment of the listening experience. Generally this uses two front (extras) and two rears. The original concept was to run the front speakers throught the unit but is best used with an extra two channel output into the DSP to keep the front two as pure as possible. This approach offers unlimited processing options but I just use a Jazz and a Chamber setting depending on the music. Since this is infinitly adjustable as both effect and volumn, you can create the effect that best suits your room and expectations. You can put a pipe organ in a cathedral with extreme reverberation and feel you are in a hugh space. These units are often available at Audiogon. I use in-walls and have excellent results. You can also turn it off. I am using Watt-Puppy 7's with high end stuff in an excellent room and the Yamaha adds a little "feel" when I want the ambience of a concert hall or jazz club. The trade offs are more than acceptable. Good luck.
As I and Kkurtis both stated Yamaha reciever is going to be your best bet for 5 channel stereo. He summed it up quite nicely. happy listening.
Calanctus...All the matrix multichannel schemes involved out-of-phase signal being emphasized in the rear channels, and deemphasized in the fronts, with the exact ratios varying somewhat between systems. The SQ LP system also involved some plus and minus 90 degree phase shifting which allowed a SQ decoder to provide better separation. All systems work best when the recorded material was encoded for the particular kind of decoder used for playback, but there is enough commonality between schemes that decent results may be achieved with differing schemes.

DSP (Digital Signal Processing) uses delay and recirculating signal to create an artificial echo that simulates hall acoustics. Usually the playback system includes a way to select different amounts of this echo effect, so as to simulate large and small halls. Outboard equipment for DSP were the first consumer applications of digital technology to audio, and replaced metal spring devices that were previously used. Many present-day surround sound processors include DSP...why not, because it is easy to implement since the signal is already in digital format. My Rotel SS processor has DSP, but I rarely use it. If I want to do multichannel playback of two channel material I usually use Dolby Prologic II. PLII has a useful three channel mode that gets me a signal for the center front speaker without any rears. DTS sends less to the rears.
Thanks Kk, Greg, Eld. Intereesting to know about the Yamaha, but I suppose that newer technologies such as Logic7 and Trifield could have an edge for sound quality.
They are all different;

In order of intrusiveness (changing timbre and adding its own sound)

Yamaha DSP (these are great on anechoic recordings otherwise there is delay on delay)
Logic 7 (not as good as maybe it should be thickens and blotches the sound)
Dolby Prologic II (a little splashy in the rears but good timbre tracking)
Trifield (as transparent as it gets at the moment)

Trifield is designed to work with regular CD's and like Dolby prologic 2 is a little more advanced than Eldartford indicates as they can consider arrival times and a variety of phase angles. etc.
The Meridian 861 or G68 would be a very good way for you to go. Also, while I agree the 861 does seem very expensive at first, once you figure in the vast capability it has now and the ultimate upgradability it provides for the future, it is a very good investment!