# Right amplification size for back surrounds



## Crapgame (Jun 15, 2010)

Hello everyone. I am a big HT watcher. I built a dedicated HT room in my basement with some high end items. My concern at this point is my rear surround amplification. I currently have an Emotiva XPA-5 which is pushing 200x5 to my L/C/R and RR/LR. I am not certain if I need to add a 200x2 amplifier to cover my rear surrounds or if an Emotiva 125x2 amplifier will be sufficient. BTW my back surrounds are Paradigm 6-1/2" in-ceiling speakers. I am choosing Emotiva because of their product quality, system compatibility and appearance. Does anyone have any suggestions for my rear surround amplification? Will the 125x2 work? Thanks alot.


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## Osage_Winter (Apr 8, 2010)

Hello Crapgame and Welcome to the Forum!

Surround channels do not necessarily need as "much" amplification as the front three channels in ordinary circumstances, as they're primarily in the soundstage for ambient support and effects fill-in, so hundreds of watts for these types of speakers dedicated to the rears or rear surrounds, etc. aren't really necessary IMO. In fact, in my next upgrade, I want to amp, I think, just the front three speakers with, say, a good three-channel model from Emotiva and let my next AVR handle powering just the surrounds...


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## Jungle Jack (Jul 28, 2009)

Hello,
Welcome to Home Theater Shack.
If you are using an AVR as your SSP, the Amplifiers in the AVR should be more than sufficient to drive 2 channels. 
Cheers,
JJ


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## tonyvdb (Sep 5, 2007)

As already mentioned, The surround channels dont get used nearly as much as the front three An AVR with 75watts per channel should have no issues driving them "if" you use an external amp for the mains.
If you are set on driving all your channels with external amps an amp with between 75 and 100watts per channel for the surround channels will be more than enough.


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## selden (Nov 15, 2009)

If your rear surround speakers are the same as your side surround speakers, then their amps should have the same power ratings as the amps used for the side surrounds.

To a certain extent, how much power you need depends on what movies you watch and the settings you're using for Dolby Prologic IIx. (Relatively few movies have 7.1 audio tracks. Most are 5.1, so PLiix needs to be turned on to get any sound from the rear speakers.) Some movies generate as high a sound level in the (side) surrounds as they do in the front. How much of that gets into the rear surround speakers depends on the PLIIx settings you're using. 

Also, THX Music Mode puts more of the volume in the rear speakers than the side speakers, while Cinema Mode makes them equal. See for example, 
http://extranet.thx.com/home/setup/listening/music.html and 
http://extranet.thx.com/home/setup/listening/cinema.html


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## Crapgame (Jun 15, 2010)

Thanks for the replies guys. Not to bash receivers but my room is 14ft x 40ft with an 8ft ceiling so I need to throw some sound around and many receivers can't give me the wattage to fill the room. I just swapped out my Denon 5800 which had 170 wattsx7 and it performed pretty well for a receiver. I am not set on my new Emotiva processor either. I have considered going to a receiver with a seperate amp for the L/C/R channels and maybe 125 watts for the surrounds and back surrounds like some of you have mentioned. Onkyo has always been good, or Marantz, or Denon. I just don't need all the multi room/multi zone stuff.


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## Crapgame (Jun 15, 2010)

Thanks for the info selden. My processor doesn't offer much in the sound fields so maybe going to a receiver that does would help overall. My Denon had THX and a widescreen sound field which took the surrounds and carried the sound to the back surrounds. It sounded pretty good! Since it is a dedicated HT room the only movies we watch are action/adventure and animation (like Disney's Pixar). Oh BTW my side surrounds are dipole Paradigms with 6-1/2" speakers, wall mounted where the rear surrounds are 6-1/2" in-ceilings, so they are same brand name but not the same speakers.


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## tonyvdb (Sep 5, 2007)

With a room that deep your going to need a good set of speakers as well not just a beefy amp/receiver. That Denon 5800 you had was a beast and your not going to find many receivers that can compeat with that these days sadly even Denon has gone down hill with regards to quality. 
A pre pro may be your best option however there are lots of good receiver that have pre outs that will cost less than most pre pros but still give you lots of features like Auddssey auto room correction and THX certification. Onkyo seems to be the one these days that offers all those features for well under $700.


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## Osage_Winter (Apr 8, 2010)

Even with those room dimensions, I would still say a receiver's power for surround channel implementation is more than enough -- _just_ for ambient effects and rear fill. :T


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