Matrix EX and ES sound; do you need a 6th channel?

I think that EX-ES matrix sound(also known as the center back sound channel) was a fabulous addition to the two rear channels in the current descrete surround systems we are using. The problem is the addition of a sixth or seventh speaker to obtain this sound, the problem being space and where to put those speakers. For instance, my surround speakers are up near the ceiling at the back of my room facing each other. If I added a sixth speaker, it would be over my head. If that sixth speaker should ever fall, it would fall on my head and I would be DEAD. It is another thing alltogether when your surround speakers are not against the back wall. Then you will probably have the room to add the sixth and seventh speaker.

Going back to my room, I noticed that I could hear sounds right over my head from the surround speakers. A test tone from the THX OPtimzier found on the Star Wars and other select dvds on one of the tests on that disc will show that you can hear the center back sound in phantom mode. So far, it has worked very well for me.

My brother had a set-up in his computer room with two NHT superzeros in the rear on stands. The two speakers were slightly towed in. I could not hear any center back sound at all. However, I have played around with speakers of various designs. One design I thought might synthesize the center back surround channel. I simply used a doorstop on each speaker and had them tilt slightly inward. The center back surround channel came out in all its glory. I know that it was working great because regular prologic rear sound collapsed dead center. It is possible that this would not be the case with the current additions of Dolby Pro-Logic 2 and similar two to five channel made into descrete type sound.

There are some receivers that have a VIRTUAL mode to reproduce the sixth channel. I cannot vouch how well this could work. The Pioneer 514 and 515 receivers have this mode. Yamaha's htr 5730 and 5830 also have this mode as well.