With the appropriate calculation, show that an inverse square decrease in intensity is equivalent to a fall-off of 6 dB for each factor of 2 in distance from the source.

this isn't me being lazy, I honestly can't find the equation in the book.

too big xD
Mesa Single Rectifier
Marshall 1960A vintage
Rg3exfm1 w/ EMG 85/81
Big Baby Taylor Acoustic
Ibanez TS808
i refer to Touji-Za-Nai's post for a summary of all my opinions regarding everything.
I have no opinion on this matter.