The second coming of this thread has been interesting. And your recent posts make clearer what you were getting at with the weighting and music content stipulations too.
If the underlying question is about amplifier power I'd comment (perhaps repeating things said originally) that A-weighting might make sense for eg a system powered by said amp supplemented by powered subwoofers. The amp will be delivering power to the circumscribed frequency range. But that's rolling off quite steeply below 1000 Hz which is a significant reduction. B-weighting—rolling off below 300 Hz and somewhat less steeply—would be a better choice for your investigative goal I think.
View attachment 547148
But if we are interested in amplifier power needed to drive a full range system then it makes no real sense to ignore bass output. You'd want C-weighting at worst, or flat—hence the Z-weighting that I routinely use in Decibel X.
We should also factor listening distance—watts producing given dB at one metre won't suffice at three or four, obviously. So at my current ~3 metre setup the calculations run this way:
View attachment 547150
I've set sensitivity and listening distance for the system, and used 105 dB as true peak with headroom at zero (for argument's sake, we could enter those numbers the other way with the same result). That number is also around the highest I've measured playing music at the listening position. My amp—a stereo Krell KAV-2250—is rated to deliver 500 watts/channel into 4 ohms so we're good, for the highest levels I'm likely to play at home with any regularity. That's quite loud of course although it corresponds to much lower dBA (maybe 90-95). And if I'm playing metalcore or techno (eg the genres I'm more likely to play loud) certainly most of the power delivery is needed for the bass, and the corresponding
average dB level for the midrange is often more like 80-85. In other words, the levels are not ear-bleeding or unrealistic (nor as loud as actual performance in those genres or indeed classical). That latter number was also my poll selection.
Now I'm also running Sonarworks DSP with a maximum boost of 6 dB. If we add that number as headroom, the required power increases to 898 watts. Looks like I need a bigger Krell. I can mostly get away without that because actual peaks are instantaneous and my amp has a stiff power supply (2kW) and a good bank of output capacitors. We are also helped by room gain and may not need to provision for absolute worst case.
We are pushing my amp though, it's getting pretty hot and I'm likely hearing distortion increased at that range on the output curve—at least when I've listened to the bigger Krell monoblocs (driving bigger speakers admittedly) the sonic effect is cleaner at the same 105 dB peaks. Let's also consider when my renovations are done, deploying in a larger room will increase listening distance to the 4-5 metre range. I'm not going to rely on a 10-watt amp any time soon.