Originally Posted by sherman9800
You would not notice a small approximate 20 watt difference in power. The power gets lower every time you add more speakers to your receiver. And you only need 32 watts to reach reference 105 db peaks on your speakers.
Your listed speakers are 90db sensitivity @ approximately 1 watt. Which is good efficiency.
They are a little small to really go crazy with and you would need much more power than even 125 watts in order to drive them to obscene levels, which would probably result in them actually breaking up and causing distortion because the speakers are not that large.
The 4i is listed at 90dB at 2.83V RMS. For 4 ohm speakers, that would be 87 dB/W, which is still good.
Ignoring any room gain, you'd need 63W to get 105 dB at a 1m listening distance, rather than 32W. (105 dB peak is the THX recommendation for home theater. It's really loud; 85 dB continuous, another spec, is supposed to cause hearing damage with prolonged exposure.) At 3m (10 feet), you'd need 568W for 105 dB! The max power suggested for the 4i is 150W. If you really want loud, medium to small bookshelf speakers may not be the best solution.
This is naïve arithmetic, I admit.
If I a) owned 4 ohm speakers and b) tended to worry, I might consider an AVR with Class D amplifiers, like the Pioneer SC-LX models. The VSX-LX503 is not
class D, unlike the older SC-LX501. Unfortunately, the surviving class D models tend to be expensive.