My chart was 4 ohms. the (I think) "standard" 2.83V signal yields 2 watts at the speaker via increased current.
If my chart is 8 ohms, it shifts a row, with 1 watt as the power at the 2.83V sensitivity..
View attachment 102004
It's not meant to be anything more than a general example of "louder requires more power and much louder requires much more power".
The following lines in Post #27 are inconsistent with one another:
85 2.83 0.707 2
Edit: the power sensitivity of 85 dBSPL / 1 W / m is equivalent to a voltage sensitivity of 85 dBSPL / 2 V / m with a 4 ohm speaker.