Multi-channel Stereo mode is another story. It can easy place a strain on the receiver. That's not the case with external amps in place.
I used to think that but now I think that is actually
overrated.
Think about this, in a small, medium to medium large room you can typically get 3 dB more from the 2nd and 2 dB for 3rd speakers, and then another 1.5 to 1.0 dB for additional speakers up to 7 speakers.
So going from 2 channel stereo to 7 channel stereo, you will gain another 5.5 dB, so if you need 10 W to get the spl you want for 2 ch stereo, if you set to 7 ch stereo, you will need only 2.8 W total for the same spl, say you want to double the volume/spl/loudness when playing 7 channel stereo mode, you still only need a little more than half total watt of that require for two channel stereo. People normally listen to 7 channel stereo for the effects, not really about wanting louder because then they can just crank it up.
In a large room, it may be a little different, otherwise, it really doesn't mean you need more power for the surround channels when in 7 ch stereo mode unless you have speakers for those channels that have relatively lower sensitivity, impedance and higher power handling capability.
An external power amp will make no difference if you are not actually going to come close to needing the extra power, and yes I am talking about peaks too, not just average spl/power requirements.
Measurements will show that I am right.
By the way, you do know I have my fair shares of external power amps so I am not being sour grapes, it is about scientific facts that are easily provable, not hearsay that are often there due to misconceptions..
Again, to be clear, my comments are based on the conditions I specified, there are always conditions under which an external power amp will contribute to less distortions at the spl the user needs, but then even under those exceptional conditions, we all know, 200 W (Monolith) vs 120 W (AVR) isn't quit 3 dB more and that's why for people who is after more power, I would tend to recommend 300 W amps, and those that could do much better in terms of dynamic output, in order to make a real/significant difference.
