Comment by ComplexSystems

The way I learned this, at least, 6 dB is what corresponds to a doubling of amplitude, but human ears compress this so it's 10 dB that corresponds to a doubling of volume - this is how the "bel" was supposedly calibrated to begin with. But that wouldn't mean we hear volumes on a linear scale in terms of bels, but rather still logarithmically (perceived volume would just be compressed using the function x^(3/5), which looks closer to sqrt(x) rather than log(x)).