If I am seriously listening to music, which is not POP music, loud passages are around 85 to 90 db. Peaks can be 10 times that but they are so short most Sound level meters don't record them accurately always. Bass peaks are easily measured pushing 96 with classical recordings. Telarc and Reference Recordings can get a little on the extreme side as can some of the older Mobile Fidelity Recordings.. I have some of my own recordings where peaks can be much higher than average levels and I normally reduce the level for loud passages to be about 85 db. I loose 10 db to 8 db in level from the level 4 ft from in front of my speaker which was the old standard. So that means both speakers have to put out about 108 db total for me to hear 100 db at my listening position. Thats about 20 to 30 watts for both speakers combined. I have a total of 500 watts per speaker, not including the super tweeters. I have only seen the Power Guard lights flash once or twice playing the Telarc 1812 Overtures when the canons fired while I was being a little crazy. Even when I pull out some old disco stuff on 45 rpm singles, of Donna and the BEE GEEs, I seldom go above 95 db, and that music is highly compressed with very few peaks. When I have friends over 85 db to 80 db are normally loud levels. 2 watts or so. My speakers are 10 db less efficient that Corner Horns so cut your power requirements by 1/10 how much power you would need. Mac speaker owners, my 2 watt levels are about 12 to 16 watts with XRT 28's XR-7's and ML-2's. Magico speakers bout 12 watts, too. So where I might need only 60 watts on a rare occasion, for my speakers. Magico and Mac owners might need 500. And if I should use 200 watts, they would need 2000. And Klipsch would only need 20. I wonder if the speaker manufacturer are into collusion with the amp companies? I can remember when 75 watts amps were the top of the line, unless you bought an industrial amp like the MI 200. Thats why Paul designed his speaker to be efficient and produce way over concert level with 30 watts. We should be so lucky if every one did to day!!!!!!!!!!