Originally Posted by Erod
I've been researching and asking a lot of questions about this lately, and here's the general rule as I can tell.
For home theater, if you have subs with their own amps, all you need is a quality amp with 100 watts per channel and you'll have more than what you need for your fronts and surrounds. It'll barely sweat even at 85 dB. Your surrounds just don't need much power.
If you listen to two channel music loud without separate subs, you need more beef.
So you should go with less amp if you don't need it. It'll run cooler with less chance of signal noise.
I think you are WAAAAY underestimating the capability one needs to achieve clean, uncompressed, low distortion reference level playback using commonly available retail brand speakers.
Lets assume speakers with 87 dB efficiency which is somewhat average. Sure, some mfgrs advertise higher, but these are VERY often inflated.
In order to reach reference level peaks of 105 dB, one needs to double power 6 times as 105-87= 18dB increase. Every 3 dB takes double the power. So 18/3 = 6 doublings of power. Now we need 64 watts in order to barely eek out reference level playback transients. However, this is at 1 meter distance from the speakers.
Lets assume we are 12 feet from the speakers, or 4 meters. Every doubling of distance from the speakers reduces SPL by 6 dB. From 1 to 2 m reduces SPL by 6 db, 2-4m reduces another 6dB. We just lost 12 dB from our 105dB peak at 1m. This puts us at 93 dB peaks from 64 watts with 87 dB speakers. But wait, we need 105 dB. So lets double our power enough times to reach 105 dB. We have to double our power 4x. 64x2x2x2x2.
So we need 1,024 watts from our 87 dB Polk or whatever retail brand speaker to hit reference level SPL. We all know that no retail speaker made will handle this much power, nor will it handle it with low distortion and without compression.
This is a big reason why most folks can't tolerate reference level playback....they assume their system can handle it but in reality our ears are being assaulted by extreme distortion and compression at this level from average retail speakers, probably even Klipsch with their falsely inflated efficiency numbers.
If you want clean, uncompressed, low distortion, dynamic, powerful reference level playback, might as well go with real, high quality, high efficiency speakers such as those made by PSA or JTR. Or DIY some speakers from DIYSoundGroup.
And for the record, I am nowhere close to full reference capability in my system(other than subs
). I've been in reference capable rooms where reference level sounded comfortably listenable(although very impressive), and more listenable than my system at -15 to -10 MV.
In comparison, a true 96 db efficient speaker needs 32 watts to hit 105 dB at 12' listening distance. A 99 db speaker needs 16 watts. Subtract 5 dB from any number the Klipsch marketing department advertises.
I currently have 87-89ish dB Hsu HB1 MK2 bookshelf speakers and HC1 MK2 center. Although my speakers are probably the last item I will consider upgrading, I won't buy anything with less than 95 dB efficiency if and when I do upgrade. My last AVR upgrade did add 3-5 dB of tolerable headroom to my system from the increased power, although that was not the primary reason I upgraded. My old base model RXV-375 pooped the bed and I ended up with Denon X3300 primarily for Audyssey XT32 and subeqHT.