The clear answer is no, according to Audyssey Laboratories when the company unveiled their Audyssey DSX surround processing technology this past week. Audyssey DSX (Dynamic Surround Expansion) promotes the idea that human hearing systems are capable of perceiving sound from more directions than can be delivered by conventional 5.1-channel systems and that adding channels where they have the most impact achieves the goal of creating a more enveloping and immersive soundstage. The concept, which is supported by solid research, states that human perception is more heavily weighted towards the front than the sides or behind the listener. As a result, Audyssey DSX provides a pair of Wide Channels (LW and RW) positioned at 60-degrees from front center and a pair of Height Channels (LH and RH) positioned at 45-degrees elevation. According to Audyssey, adding more surround channels has less impact than the front Wide Channels. Simply put, Audyssey states "Width before height, front before back".
Unfortunately, I was unable to attend their presentation, but according to a few colleagues who attended the demonstration, it was quite impressive. However, I can state with certainty that for me there is nothing more enjoyable in home entertainment than an immersive, enveloping sound experience and if Audyssey is correct, this may be a giant step forward in home audio reproduction. I hope to hear the demonstration in the near future. This is just an overview; for more information, visit the Audyssey website.