what is purpose of home theater processor?

I dont agree, a movie is made to be listened to in full surround and most enjoyable when viewed that way. Having said that if you have a system that excells at music it will easily perform well for movies but the reverse cant be had as easily. Some really enjoy 2 channels for movies but that seems very out dated to me, like how we watched in the 80's and earlier.
Music in general is made for 2 channel, atleast it used to be and my point is it sounds best that way because thats how it was made to be enjoyed, movies on the other hand in 2 channel is a step backwards, thats why it is is often called a "down mix" when selected for 2 channel only.

I will second Cadnliz comments on this topic. Movies especially anything made in the last twenty years are meant to be enjoyed in full surround. If you are seriously considering assembling a home theater system you should seriously consider going the full surround route, as a matter of fact I wouldn't even call it home theater with strictly 2 channel sound, I would call that a movie thru your stereo. The last point I will make is a simple one, if the filmmakers took the time and effort to make the movie and played it at the theaters using multi channel sound tracks, don't you think to get the best representation of that at home you should utilize the same multi channel playback. Wow and that all comes from a tried and true 2 channel guy LOL!!

Kal Rubinson has been a strong proponent of surround sound for music in his Stereophile column. My limited experience (an Arts SACD of Corelli violin sonatas played on a Cary Cinema 11a) is that surround can give a greater sense of ambience than can be achieved with stereo. I was amazed. But I wouldn't sacrifice stereo sound quality just for surround music. You can have both, but it raises the ante.

db

10-30-10: Chadnliz
>Having said that if you have a system that excells at music it will easily perform well for movies but the reverse cant be had as easily.

That's backwards.

An excellent home theater system will produce 105dB SPL main channel and 115dB SPL LFE peaks at the listening position without distortion or thermal compression.

It'll do fine on source material mixed for nearly 30dB of dynamic range.

And it'll sound great on music, which forms the backbone of most films.

"Audiophile" systems which handle scale-model music at less than realistic volumes may suffer physical damage in the same environment, and are at least likely to have distortion and thermal compression problems.

Of course most "home theater" systems aren't excellent in the same way that most "2-channel" speakers aren't.