Log?Liner

stupid question, but whats the difference??? i dont get it when i it the log button...

linear means 10 20 30 40 50 ... [f(n)=xn]
logarithmic means 1 2 4 8 16 32 64 (based on 2, other bases could be used ...) [f(n)=xb^n, or reverse ...]

according to the manual, on low levels, log is better to view

our hearing works in log not linear way. so log pots (controls) are used for volume.
how this relates to the log button, i'm not quite sure.