Hello Mr widget
I am a different opinion. If I have a speaker with a 97dB/W/m Woofer, and give 1 watt performance in the box then, I have a sound pressure at 97db by 1m. If I have a speaker with 2 woofers have given each of the woofer only 1 / 2 watt. Each woofer produces only 94dB sound pressure. Both Woofer together again produce 97 dB SPL.
I think that at the definition of 1 watt little problems. 1 watt is an 8 ohm Box at 2.88 volts. Many manufacturers are now simply measuring 2.88 volts. We all know that the speaker does not ohmic resistance. If the impedance measurement for now is only 6 ohms, we have not 1 but already watts 1.38 watts, and we have a higher sound pressure.
Sorry for my bad english, its from online-translater.
regards
juergen