Here is what I wrote for a previous posting.
Multichannel discs, and why.
There is a limited selection of Multichannel discs, and some controversy regarding the merits of multichannel. Certainly there are some inferior discs, but there are also a few that are superb, and demonstrate the potential of the medium to far surpass stereo.
Here are my thoughts on the subject, and I hope that others will offer similar info, perhaps with regard to pop/rock music where I am completely ignorant.
1. The most suitable type of music for multichannel is a small group of musicians like a classical quartet, or a jazz band. The recording can place one instrument, more or less isolated, in each speaker. This has the effect of transporting the musicians into your listening room, rather than projecting you into the performance space. The result is striking. The best examples are Tacet DVD-A discs of chamber music (Mozart Flute Quartets is a good one) and Warner DVD_A "The Bluegrass Sessions...Bela Fleck.
2. "Antiphonal" music is composed with two or more separate groups of musicians in mind, and is a natural for multichannel. A Sony disc of E. Power Biggs playing four separate organs at the same time in a cathedral in Freiburg is a good example. The music is Bach Toccatas and Fugues, and his performance, where the musical phrases are answered back and forth between instruments puts an interesting new twist into these old war horses. The music is very antiphonal, but we never realized this because you usually get to play only one organ at a time.
3. A Telarc SACD, "The Sound of Glory" illustrates another aspect of multichannel. This is a performance by the Mormon Tabernacle Choir, 400 voices strong, and backed up by what must be the mother of all organs. It's a huge soundstage, and it takes at least five speakers and several powerful subwoofers to do it justice.
4. The Sony disc of Mozart Sinfonia Concertante (Midori, violin and Nobuko Imai, viola) is an orchestral piece which places a significant part of the orchestra (not just ambience)in the rear speakers. This troubles some listeners, who are used to hearing music from a distance of 100 feet or more. However, for anyone who has played in an orchestra, or sung in a choir this perspective is very realistic, and certainly more "involving" than straight stereo.
5. Polyphonic music, where there are about ten musical lines going on at the same time benefits from multichannel which permits better isolation of the different parts. Teldec DVD-A Chanticleer Magnificat (Gregorian Chants) is an example.
6. Last but not least there is some music that just asks to surround and roll over you like a wave. Of course the example is PentaTone SACD of Rachmaninov Piano Concerto No. 2, famous as the world's most effective seduction music.