Hello. Looking for advice on surrounds with newer DTS-HD MA and Dolby TrueHD encoding. These encodings can handle up to 7.1, but majority of blu-rays are 5.1 using these encodings of which side/rear surrounds would be same sound.

Question is, would any benefit be gained from having towers (floorstanding speakers) as side or rear surrounds, or would it make more sense to stick with bookshelf and surround speakers?

I'm contemplating the following setups:

#1 (my current setup)
fronts: polk RTi10s
center: polk CSi5
side surrounds: polk FXi5s
rear surrounds: polk RTi6s

#2
fronts: polk RTi12s
center: polk CSi5
side surrounds: polk FXi5s
rear surrounds: polk RTi10s

#3
fronts: polk RTi10s
center: polk CSi5
side surrounds: polk FXi5s
rear surrounds: polk RTi8s

Don't have a sub yet. I'm thinking #2 or #3 would provide benefit as they are better speakers as rear surrounds. But what does everyone else seriously think?

Again, I'm considering the setup with the new DTS-HD MA and Dolby TrueHD encodings and am wondering if #2 or #3 above would provide any benefit.

-Thanks

#2
I can just imagine 5/7ch stereo using such a setup. :D

It is not so much about towers vs bookshelves, but it is more about extension.

Yes, towers will usually extend much lower than their bookshelves counterparts.
If that means going with towers, then go with towers.

The fact is, there is a lot of music (bass) in movies, and you want speakers than can extend low enough all around.

Personally, I went with towers for fronts and rears. :)

In my old system, pre HD Audio, I used to used Klipsh Towers for rears, sideways and hung from the ceiling. And I had 2.5 way (rear mounted midrange for dispersion) speakers on the side.
It worked well!!
My new system, with HDMI audio, I wanted a complete system, timber matched all around.
I used Bi-poler speakers mounted on the walls for side surrounds, and center speakers for rears, again, hung from the cieling behind the seating positions. That works well.
The theory is bass is non directional, so you shouldn't need the low extention of towers for side/rear.

and center speakers for rears, again, hung from the cieling behind the seating positions.

Do you mean center channel speakers? WHat do you mean by "center speakers".

Also, I wouldn't hand the towers. I'd just have them on the floor.

Also, if a sub was thrown into the mix and since bass isn't directional, really would the extension of the extra bass from the rears make a whole lot of difference?

Don't have a sub yet.

#4 - Current setup and a good sub would give you the most bang (literally :)) for the buck

Also, if a sub was thrown into the mix and since bass isn't directional, really would the extension of the extra bass from the rears make a whole lot of difference?

Only bass and LFE below a certain point is non-directional.
I can pin-point anything above 60hz.
Not only that, since subs are mechanical, there is a good amount of give away regardless of how low the frequency is.

Also, if your rears are closer to you than your fronts (most likely case), having the rears output a good amount of bass helps with feeling the sound without needing to play very loud.

You need a sub before you need towers all the way around.

The high def formats you mention sound great on good equipment, but having towers for surrounds won't really help. Most of the sound comes from the front. Using high def source DVDs will make almost any reasonable system sound better. But you really want to benefit from better bass output as well as the improved resolution and clarity. Since your surrounds are rarely getting much signal to them, you'll get hugely more bang for the buck by adding a good subwoofer to your current system than adding tower surrounds. I think tower surrounds would be pretty weird and overkill anyway.

Actually, looking at a picture of the Polk front speakers you mentioned, looks like they have decent bass capacity as it is, so you may not be in a huge rush to get a subwoofer. But I'd definitely not get anything big for surrounds (and you're not going to find many 7.1 recordings either, even in the high def formats.) I'd put a little more money into the surrounds just for quality if you found some that made a difference, but I definitely wouldn't get big ones. I have $6,000 retail front speakers and a $6,000 retail subwoofer, and I just have small surround speakers that attach to the wall. I might upgrade my center channel, but I won't upgrade the surrounds. (Just side surrounds, no rear.)

Also, if your rears are closer to you than your fronts (most likely case), having the rears output a good amount of bass helps with feeling the sound without needing to play very loud.

This can be done more easily and less expensively by simply adjusting the subwoofer. If the surrounds are closer than the front speakers, they are most likely adjusted down anyway for proper mix with the receiver setup. If the surrounds are close enough to "help you feel the bass" more, then they're close enough to set the surround mix out of balance and other surround sounds will seem too loud.

+1 to the get a high quality subwoofer option! For HT, I would recommend spending at least the same amount of money on a subwoofer as you spend on the front speakers (if not more).

With a high quality subwoofer that has a low distortion (or is driven at a low enough volume not to have high harmonic distortion), an 80 Hz or lower signal is not generally localizable. What this means is if you crossover the rear and surrounds at 80 Hz (or even 60 Hz if your pre-pro/receiver allows), you won't know the bass is coming from a sub or the speaker.

BTW, your current RTi6s is supposed to be F3 at 50 Hz, so they already produce enough low bass to blend in well with a subwoofer.

This can be done more easily and less expensively by simply adjusting the subwoofer. If the surrounds are closer than the front speakers, they are most likely adjusted down anyway for proper mix with the receiver setup. If the surrounds are close enough to "help you feel the bass" more, then they're close enough to set the surround mix out of balance and other surround sounds will seem too loud.

Yes, the rears will be adjusted down, but they will still help in filling the room with bass.

I am certainly not arguing that he needs a sub for movies.
I am saying that for applications where the sub is not involved, having full range surrounds helps.

Plus, this argument of the surrounds not getting as much sound as the fronts is pointless.
It is like saying, since I don't listen to music often, I don't need the best speakers I can afford.

My surround get plenty of sound during movies (and certainly during music ;) ).
Again, if OP is interested in 5/7ch stereo, this would make a world of a difference.

My surround get plenty of sound during movies (and certainly during music ;) ).
Again, if OP is interested in 5/7ch stereo, this would make a world of a difference.

+1. Full-range speakers in the side channels is a big benefit for things like SACD/DVD-A and surround concerts. These sources often have full-range sound in the surrounds. Having serious bass in the side channels is very noticeable and changes the whole experience. Of course it also requires enough power to match the front channels. Thus far, back surround channels are doing little more than ambiance effects and full-range speakers might be over-kill.

This sort of thing is always about degrees. The benefit of full-range side speakers may not equal the benefit of a good dedicated sub and the benefit of large side speakers may not equal the loss of not having back surrounds, etc., etc.

The last 10% of performance is always the hardest to obtain, but sometimes the most rewarding.

Thank you all very much.

It sounds like best bet is to first get a really good sub. I've had my eyes on polk subs. Any opinions on polks or others? RTi10s went for about $1100 a pair retail. So according to one guys opinion about $1100 for a sub is the way to go?

Also, what is F3 when the guy talks about my RTi6s? How did he find that information? I'm now wondering if my RTi6s should be side surrounds instead of back surrounds. It sounds like more bass comes from the side surronds than the backs. The FXi5s I was going to put on the sides are di/bipoles, but I'm uncertain what to do now. THX says only directional speakers in the back which would mean RTi6s. As you can see from the link below, even the picture depicts di/bipoles on the sides.

http://www.thx.com/home/setup/speakers/71.html