Played few tracks, looks like the "Average" is between 69dB and 80dB and "Max" between 78dB and 90 dB - all A weighted. There's also "Peak" values at 99dB!
If the average spl is between 69 and 80 dB on moment by moment basis, then the overall average is about 74.5 dB, say 75 dB.
This then, I fed to the online
Peak SPL Calculator , for my speaker's rated sensitivity(92dB), distance(11ft), Away from speakers..,looks like 5w gives me 91.5 dB at listening position.
That calculator is based on sensitivity X dB/W/meter, and that is for 8 ohm nominal impedance. So for 4 ohm nominal speakers such as yours, you should subtract 3 dB from the calculated value, so 5 W average will get you 88.5 dB average, and for 75 dB average, you only need about 0.115 W.
Can you pls clarify your comment "then take the number, multiply it by 200 to 300 (better obviously) " , in this calculation , so I am not misreading your recommendation?
My comment about multiply it by 200 to 300 is to allow for peaks in the movie and music contents that may have as much as 20 dB peaks. So in your example, to allow for 20 dB peak on top, ie. 95 dB spl, you would need 100X the power. If you want to have another 3 dB of headroom on reserve, then you need 200X the power.
200X0.115 W = 22.5 W
You only need 22.5 WPC, to target 75 dB average/95 dB peak per speaker, and will still have 3 dB headroom.
75 dB average is just about as loud as I would like for serious music enjoyment, but that's not THX reference level. If you target ref level, that's 85 dB average 105 dB peak, you would need 10X22.5 = 225 W. The Denon AVR-X3400H (rated 105 W average 210 W peak, 8 ohms) can do it without clipping, but you would have only about 1 to 2 dB head room based on measured results I have seen.
I hope that answers your questions.