So I asked a question regarding amplifier needed for a pair of surround speakers... I just found this resource and I thought I would share: https://myhometheater.homestead.com/splcalculator.html You can enter speaker sensitivity, amp power, distance from speaker, number of speakers, and placement and it will do the math calculation for you to reach a certain db level. Play with the amp numbers and you will not see the upper end db change that much. However, remember there are peaks as well as higher distortion in smaller amps as you reach that higher RMS. This calculator helped me realize that with higher sensitivy rears as well as closer placement to the listening position, I can get away with a 60w amp and still have the same dynamic power as my main 400w amp. Crazy. PS - peak THX ratings is 115db . I am only at 110, but I probably listen to movies way lower than that.