I think your questions have basically been answered. That is, music and movie contents vary a lot, the signal is not a steady sine wave but a combination of sine waves that vary with time. That is a fact!
So it is not possible to answer your specific question as to how many "watts.....", with reference to the power output "sweep test" or when watching movies at cinema level using whatever speakers. It really cannot be answered correctly even if we try!
Sweep tests and movie signals are very different on the magnitude and time/duration basis. For example, sweep test such as those Gene conducted on the A6A was based on continuous sine waves at 1 kHz, and the test duration was not "continuous", not literally, but are of a short duration (like minutes??). Movie signals are nothing like that!
Now if you want to know (not sure if you do) how much power the A6A can output when connected to 4 and 6 ohms resistor test loads, take a look of Audioholics and Audiovision.de's tests and you will see some results for the A6A, lucky you..
Yamaha RX-A6A (review) (audiovision.de)
Their bench tests show, using 1 kHz test signal, at unspecified THD level, but presumably 1%:
1) 219 W 6 ohms, 2 channel driven..................... Calculated voltage = 36.25 V
2) 270 W 4 ohms, 2 channel driven..................... Calculated voltage = 33.59 V, current =
8.22 A/ch.
3) 123 W 6 ohms, 7 channel driven......................Calculated power = 861 W, V = 27.17 V, current = 4.53
A/ch.
4) 151 W 4 ohms, 5 channel driven......................Calculated power = 755 W
Using the power formula, P = V^2/R = I^2*R (based on a resistor load that is typically used for such bench tests)
where P is power, V is voltage and R is the resistance, the above calculated values can reasonably be assumed to be the output voltage, current, and power limit.
Based on the Audiovision.de's test results shown in 1) above, it would appear that the RX-A6A can output about 36.25 V at 6 A, or 32.86 V at 8.22 A on per tested channel basis, for the duration of such tests that probably last no more than a few minutes.
Based on 2) above, the current limit would be about 8.22 A, but based on Gene's test, I would use 8.4 A or 16.8 A for 2 ch (see linked test by Gene below).
Based on 3) above, it would appear the A6A's power supply can output 861 W for the duration of the test, for 6 ohm test load
Yamaha RX-A6A 9.2CH 8K AV Receiver Bench Test Results! | Audioholics
Now, as an example, if you have 3 4ohm resistor and 4 6 ohm resistors all connected to the A6A, then the 4 ohm loads will draw current up to the point the power supply cannot handle, same for the 6 ohm resistors, when you gradually increase the volume dial.
So let me do the following tests (on paper, calculated only, obviously):
As you wish, I would connect all speakers as you mentioned to the A6A, and increase the volume until the nanny stopped the test.
Just prior to the nanny stopping the madness:
Based on the unit reaching it's current limit of 8.4 A*2 = 16.8 A first, as dictated by the 2 channel 4 ohm load test:
Apply Ohm's law, that is V = I*R, so V = 8.4X4 = 33.6 V, that's within the calculated voltage limit of the A6A.
So let's use 33.6 V as the voltage limit for the case of having three 4 ohm loads and four 6 ohm loads:
Power into the 4 ohm load = 33.59^2/4 = 282 W, or about 2*282/3 =
188 W into each of the three 4 ohm resistor load
Power into the 6 ohm load = (2*282)/4 =
141 W into each of the four 6 ohm resistor loads.
Total power output = 3*188+4*141 = 1128 W, that would exceed the power limit based on Audivision.de's test with 7 ch driven into 6 ohms, that is a total of 861 W. We can use the ratio 861/1128 = 861/1128 = 0.763 as a correction factor to estimate the maximum output into you three 4 ohm and four 6 ohm loads, so the final estimated outputs will be:
188*0.763 = 143.4 W for each of the three 4 ohm loads, and
141*0.763 = 107.58 W for each of the four 6 ohm loads.
The above worked example are based on:
a) Use Gene's bench test results on the A6A to calculate the assumed current limit based on the 4 ohm test.
b) Use Audiovision.de's 5&7 ch power output results for the 4 & 6 ohm loads (Gene did not include those tests)
c) Use the results based on 1% THD, and assume (not specified) Audiovision.de did their test based on 1%
d) Obviously such sweep tests are done using resistor loads, not actual speakers
The results are not "continuous rating", not literally, but the term "continuous" are often used by reviewers if they use continuous sine wave test signal as opposed to sine wave pulses, such as x second on, y second off etc.
@gene can tell us the actual duration of the sweep tests and I don't want to guess.
Again, no one can answer your questions exactly because you are talking about watching movies, in that case, it depends on the contents in the movies, that obviously vary greatly among different movies.
And also depends on the characteristics of the speakers, just 4 or 6 ohm is not enough information because those numbers are based on nominal values, and "nominal" is loosely defined. You can possibly have a speaker that has higher nominal value per the manufacturer's own definition, yet it could have dips that could be narrow, or wide, could also be in the bass frequencies, or at higher frequencies. Then there is also the phase angle issue, that may not affect the current draw but it may cause the amp to over heat, or become unstable at some point, resulting in the nanny shutting it down even at lower "watts" output level.
This is just a numerical example, but you can easily see why AVRs are not tested with 4 ohm load for the 7 or even just 5 channel driven conditions. In the two channel driven tests, Gene measured 282 W, the calculated current is 8.4 A, with 2 channel driven, the AVR's power supply will have to deliver 8.4 A per channel, and the calculated voltage is 33.6 V, so if the same output is expected under the 7 ch driven condition, the transformer's VA rating will have to be 33.6*8.4*7 = about 1,976 VA, that would be a huge transformer that probably weight over 30 lbs! For 8 ohm load, that can be cut to half. And that's assuming 100% efficiency!!
I hope this helps, but I suspect it may confuse you more, so, next question.
Note: I did this in a hurry, regardless, there may be typos and calculation errors so if other members catch any, feel free to alert me and I will make the necessary corrections.
Edit: I found some errors, hopefully got them all fixed now
