@PENG I had discovered all those high-powered amps I had accumulated over the years were really a waste of money spent. When that money should have been spent on where it would have given me the most Improvement in sound quality my front L/R speakers throw in Center channel for surround sound.
By chance really, I decided to add an A/B switch so I could use both my AVR and a 2.1 channel Stereo receiver, for just use of my front L/R and Sub if I wanted to use the Sub at all for 2.1 with the 2 channel Stereo receiver. I discovered at the volume of very high output was only when those added amps came into good use. Sure you have a huge room, front main speakers with a low impedance dip or you went the full Monty, with Dolby surround, added amps more than likely will be needed.
Back to the future
Speaking for myself, Choosing an AVR to pull double duty 5.1/2.1 or what ever mode of Dolby surround is a personal choice. Were tradeoffs for me at this point.
@Trebdp83 made valid points, some don't use the DSP Processing at all with an AVR. For a true 2 channel use for music, much better options as you have stated in your post.
Absolutely true that for a large room, sitting > 4 m from speakers with <90 dB/2.83 V especially if phase angles are relatively high in the wrong place, high power amp such as >=300/500 WPC will make a difference.
People just need to keep in mind the following:
- Each time power output doubles, SPL at the mlp increases by only 3 dB.
- Each time the distance is double, SPL drops by 6 dB, yes there are some room gain but that varies and mainly apply to the bass frequencies.
- For speakers with 86 dB/2.83V/m, SPL will be 6 dB lower than speakers, such as many popular Klipsch models and some Focal's that have sensitivity 92 dB/2.83V/m.
- Those who regular listen to loud SPL, say at reference, compare to those who are happy with listening to 10 dB below reference, will need 10 times more power.
- Speakers with phase angles > say 30 degrees, combined with some of the conditions above, could cause their AVRs and/or those 100-120 W integrated amps to overheat.
Based on above, it is silly for people to keep talking about need high power amps because of their 4 ohm speakers, when there are quite a few more factors that have the same and often more impact that they need to take into consideration. There are just so much misconception in the audio world. The only way to simplify thing is for everyone to go get a Mc1kW (minimum) power amp for whatever 4 ohm difficult to drive speakers, then we don't need the weekly forum questions.
So yes, the sayings that most people don't realize how little power they actually need, and most people don't realize their amps clip a lot more often than they realize are both true.
In other words, in many cases, >300 W/500 WPC power amps can help improve sound quality, but many cases they don't.
