I think the OP is asking about the brain's perception of lower frequencies. If I'm correct what the OP really wants to know is how much more SPL does a low frequency tone require to be perceived as equal to a relatively higher frequency tone. I don't have an answer to that but I've had good luck feeding my lower frequencies around 5x to 8x the watts of the higher ones. I use towers that have an active bass section and dsp. My amp is 50 wpc and the bass is a few hundred wpc.
What’s the Right Power Amp Ratio For Bi-Amping?
Is there a “golden rule” or rule of thumb when selecting amplifier power in a bi-amp setup? It seems to me that the power should be apportioned according to the demands. Since most of the energy consumption in sound reproduction is by lows, it stands to reason I should use a much more powerful amplifier for lows than highs, but what ratio of power? 2:1? 10:1? Is there a wrong answer?