Home Theater Power Amplifier Help



Audiogon Community;

I am leaning toward separates in my HT setup, and B&W in-walls.

Right now, I am researching the amplifier power requirements for the system. The room dimensions are 17' x 17' x 7'6". The room volume is ~2,200 cubic feet.

Based on the speaker sensitivity, room size and accoustics and power output relationship I come up with a power requirement of less than 60W per channel to drive the speakers.

Do you agree?

The two subwoofers will be driven off the controller.

Possible Power Amplifier choices include:

Rotel RMB-1066 60W x 6 into 8 Ohms!

Please comment!

Happy Holiday's,
wheaton_illinois
For HT you will need more power than you think. The dynamics of dialog vs. action sequences is much larger than normal music. You will listen at higher db than with stereo and will want to be able to crank up the volume to levels you would never think of for stereo unless your a real DEADHEAD.

Remember to double the dbs you need to quad the wpc.

I would suggest a minimum of 100 wpc to provide the headroom you will need. Used amp(s) are very attractive for HT as the technology has been essentially stagnant (in the amplifier only area) for years. I would not consider buying an older video product or receiver but I would buy a set of older amps.
60 wpc out of a "typical" multi-channel amp is surely not enough power for HT, especially in a room that large and speakers that are not highly efficient.

As to using in-wall speakers, the performance will be far inferior to individual speakers in their own cabinets. This has to do with diffraction, baffle size, etc... resulting in poor soundstage and imaging, speaker localization, etc...

You are setting yourself up for a lot of disappointment and future upgrades. That is, unless you are only looking for a minimum of performance i.e. something that "works" while being "convenient" and very simple. Given the amount of labor to install multiple in-walls, i would think very seriously prior to going this route. Your local dealer / installer may tell you something different, but we have nothing to gain by sharing this info with you. Be careful how you spend your money and what you take for granted. It is FAR cheaper and easier to "think big" in the preliminary stages than to have to upgrade / change / re-arrange later. Sean
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What is the sensitivity of your B&W inwalls you have(or are considering)? Even if they're 90db sensitive, you will still do better dynamically with more guts under the hood(amp)!
Also, within reason, the kind of amp you use with an inwall system really isn't going to be the biggest factor! The biggest factor/challenge by far is going to be the "sonic limitations" that inwall speakers inherently offer.
Yes, for the most part,the inwall approach will keep your system sonic potential at a minimum, as those speakers have their challenges for sure! Usually, considering most aspects of the sound, you will not get the same sonic potential from $1500/pair inwalls that you will from $400/pr bookshelf monitors! Unless you build a "well engineered" enclosure for your inwalls, and EQ the heck out of em(plus other considerations), you won't get so fantastic of a sound in my experiences(and that's a lot). It would be ok, but not any better than even a lot of HT in a box systems for the most part.
The speakers are going to be the majority of the sound from your gear, and inwalls are your weakest link.
Might I strongly suggest, if you just do more of a surface mount for cosmetic reasons, that you go with the sonically supperior Thiel powerpoints!?! They're sonically superior flush mounts, which were judged as "best sound" at the 2001 CES show by the public, and are designed to go against the wall in a low profile!..it's a thought.
At least getting 3 of these upfront($2k used), and maybe downgrading the rears to inwalls will keep the overall sonic integrity of your system VERY HIGH! You will likely be spending more bucks than you originally thought, but not that much when you consider the 200% better sound you'll be getting...regardless of amp you'd chose for those inwalls you're considering(and the B&W inwalls are descent compared to others!)!
So, my vote is at least 3-5 Thiel powerpoints, and something like a used Parasound HCA1205a amp (used $600-700), Acurus 125x5 ($600 used), or similar(the Rotel $1k 5 channels amps are strong but descent sounding) and you'll potentially have more than fantastic sound for not too much!
Anyway, I'd recommend getting at least a better selection of fronts(again, powerpoints will amaze you compared to inwalls, or most other monitors for that matter), and you'll be WAY AHEAD OF THE GAME from the get go. good luck
Hey another choice is go to CES show in Vegas next month and check out the new stuff!
Definitely agree with other responses. Get more power! I can only hope to discourage you from buying in-walls. Look at any reputable speaker company and you will never find a cabinet made of drywall and two by fours. You lose all flexabilty and possibility of accurate set-up and maximum sound focus. I encourage you to research ON-walls, example
Martin-Logan makes a scenario (I believe is the correct name) also Acoustic Research, Legacy, to name a few.
Good Luck
Thank you! Based on your comments, I am going back to the war department (my wife) to discuss this matter further! Sometimes it is not space, money or time that is the limiting factor!

Happy Holidays
Wheaton-IL, the above response are correct, but they are coming from a perfectionist orientation. Are you trying to put together a perfectionist system? If not, and I suspect you're not, your probably just want good quality performance at a fair price, then much of the above advice does not apply. For instance, you're looking at in-wall speakers. From a decor perspective they make perfect sense, they take up no space and the cables are hidden, but they don't sound as good as comparably priced freestanders. Only you and your family can judge if the trade off is worthwhile. You might want to consider Mirage's Omnisat speakers. $400/each including stands, plus they have a matching subwoofer. As far as power goes, remember that doubling the power output only results in a 3dB increase in headroom.

I assume you live in Wheaton. I hope you're taking advantage of the excellent music series offered each year at the College of Dupage. They have interesting artists and the hall offers very fine sonics. Best of luck!
Thank you Onhwy61 for your response!

COD is a first rate college, however, I have never taken advantage of their music productions. Based on your advice I subscribed to their mailing list this morning.

Thanks again.
Onhwy61: What kind of talk is this that you've introduced into these forums ??? Reality ? I'll have nothing to do with such topics... : ) Sean
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I have the Mirage Omnisats in a 5 channel setup and have been quite surprised by the sound they reproduce; for the money...The one turning point I did not factor in when I bought them was the amount of power they need..I have a large space and was using about 100Watts from a medium priced amp. I will now be upgrading my amp to a more powerful and cleaner amp to get the volume I like out of all speakers when playing DVD.....XXX just lacked the dynamics I saw in the movies.....hope this helps a little