Is 7.1 better than 5.1

My amp and processor can do 7.1 but I only have 5.1 set up at this time. Should I buy another pair of speakers?
first read 'Sound Reproduction' by Toole, then decide.
First what is the size and dimension of your room .Next are you a big Star War fan? The reason there are not that many DVD movies set up for real make it worth your effort and dollar.Let me know I will fill you in
I originally have a 5.1 setup and bought two more speakers to make it 7.1. If the movie has 7.1 soundtrack, the extra two speakers make the sound more wraparound especially in the back. It is better, but not by much. I think the 7.1 technology is not very mature yet as many people only have 5.1 setup. There aren't many movies out there that have 7.1 soundtrack. A good 5.1 soundtrack can make the movie viewing experience very satisfying.

If you are tight on budget, I suggest you wait. Otherwise it doesn't hurt to play with a 7.1 setup.
I used to pooh-pooh the difference between 5.1 and 7.1. Then four years ago I got a 7.1 processor and my brand's matching surround speakers went on sale. Bought the speakers and brought an extra 2-channel amp out of the garage (later replaced by an Adcom 535 II) and there it was. My surround processor will matrix the rear surround channels from any 5.1 channel source, so it *always* fills in the back of the room. Then when you get a video that has a full sound track the localization is great. One example is in the Harry Potter films when they're on their brooms, zooming all around, or just about any film that involves flying, such as The Aviator.

I was able to put in a pair of Mirage OM-RS's (or whatever) for about $300 plus the spare amp I had, so it was easily worth it.
So to add a bit...

Let's look past availability which is an important determinant in its own right.

This is principally about the physical layout of the specific room - meaning how much space is there around the seating area

The way this stuff is designed, the 5.1 speakers are to the left and right of the audience about 2/3rds - 3/4s of the way back, firing across the audience (L to R, R to L)

The 7.1 pair are behind the audience firing forward towards the screen.

The more discrete sources you have, the smoother the motion of sound from one speaker to another, the more precise the placement and the greater the illusion it creates.

In many rooms, including mine (alack, alas) there is no room to fire across so the 5.1s become the rears. A dipole design helps take the edge off it but still it simply cannot create the same depth of illusion.
I disagree that a rooms size or shape is a reason to stick with 5.1. Have you heard of anybody going back to 5.1? Without room correction this could be an issue but after running room correction my small corner screen placed system simply came to attention with an incredibly balanced output. Room size may dictate the size of the speakers themselves, even that would be subject to personal preference.

7.1 offers better dialog placement for the L C R channels. The surround effects are now pinpoint accurate and do not rely on room reflection or the the front L and R speakers to convey the effect. The first thing I noticed is just how important the side channels are. It's simply more theater like. While the 7.1 media is slow in coming I find the effect on earlier soundtracks more enjoyable IMO.

Room correction software is a must and I'd stay away from dipole enclosures. Matching your current speakers with either used or discontinued speakers can make this one of your easiest audio upgrades.
Better YES. Practical NO. Of course it is better but it depends on how willing you are to invest for the small amount of 7.1 soundtracks available.
07-14-09: Shadorne
Better YES. Practical NO. Of course it is better but it depends on how willing you are to invest for the small amount of 7.1 soundtracks available.
For me, having a 7.1 source on the soundtrack is nearly immaterial. My AVP can matrix 7.1 from any 5.1 source, and does. It fills in the back and provides a more enveloping sound whether coming from a 7.1 or 5.1 channel source.

7-channel sources are growing rapidly, as just about anything coming out on Blu-ray these days is 7.1. The true 7.1 channel sources *do* provide more discrete rear channel specificity, but even in a matrix where the rear surround channels are only playing the signal common to LS and RS, it still fills in a gap that otherwise occupies the rear third of the room.

If you already have a 7-channel AVP or AVR, the additional cost of rear fill-in speakers and a pawnshop amp is minimal (e.g., I got an Adcom 535 II for $75). The only potential hassle is laying the front-to-back speaker cables.
Here is my experience. I have had both 7.1 and 5.1. The issue for me is that I have a large, open room where my setup is. Ceilings are cathedral and slanted and the room is not symmetrical. It's open space is something like 18x25 with ceilings at 9 feet and going up to the open 2nd floor.

I called my local dealer about setup and he said that he personally is not a fan of 7.1 vs 5.1. However, in my situation, he said he not only recommends it but that I should really make it happen because of the volume of space I need to fill with sound. I can tell you that once I went to the 7.1 setup he was right.

The addition of the rear two really made things come more alive. When you have a good setup the 7.1 really sings. Now, I don't even really have high-end speakers for my rear surrounds. They are only Cambridge soundworks cubes. But you have a DVD that my Anthem processes with THX and pumps the surround rears and it's just spectacular.

Now, I'm really, really happy with how my Anthem AVM20 handles the 7.1 channels. My previous lower-end Marantz didn't come close to the Anthem's sound.

I've purchased some stuff here on audiogon over the years and I've started a blog to chronicle my experiences:

I'm going to be talking about how I setup my 7.1 surrounds with Cat5 runs.

Anyway, my response is that if you have a larger room, you will likely notice a fantastic improvement as I did. In terms of practicality, yes it's a pain to run stuff, but I have come up with a lower-cost solution that I'm really happy with!

Go with the 5.1 and use the back channels to bi amplify your front speakers. The back channels have the same sound as the front.

Yes, your processor will matrix and fill in the back two channels.

This reminds me of the purist two channel crowd. Break out and join the 7.1 crowd!!

my biggest gripe about 5.1 is when there is some object (or talking person) moving from the front to the back by the side. with my long shoebox room, the object simply warped from the front to the back.

I suppose having an extra pair of speaker in between the front and the back will make the transition smoother. Is it worth it? I don't come across too many of that kind of scenes.
I shelved my 7.1 denon/paradigm setup for 5.1 cj/Dali arrangement and prefer the 5.1 due to quality of amp/speakers. I also rent lots of bluray from netflix and most are still 5.1 DTS (which sounds great)
Maybe with the improved bluray audio codecs its time to try 7.1 again.
This weekend I will try adding the studio 470 dipoles to the 5.1 mix, and then the studio 20s to see what happens. Only problem is the CJ amp is 5.1, may be a synchro issue with using the denon 5803 to power the surrounds. ?
One thing to try, would be to borrow a pair and hook them up and do a weekend of listening.

After having said that--I've set up hundreds of systems--many of which didn't have money as the mitigating factor.
The set up, in terms of how well it's done, is more important IMHO than 5/7.
The key to proper setup is listening, listening, listening.
You can, if limited by space, 'fib' to the processor to create additional space. Now, a little information is a dangerous thing.
But one system, I set up in a conference room for a recording studio. The goal was to make the sound, (this will really sound daunting, and it was) good all around the table--not centered for everyone, that's impossible, but the varying perspective that you'd have if located relative to the real position at the table, versus the center of the action.
This is a very complex answer, if you'd like to email me, or even talk about it, I can give you some good tips based on thousands of mistakes!! Most people, hobbyiests don't have time or inclination to become proficient at this.
Happy to help, and this is a terrific question.