what is the use of an octave pedal????? my fren tried one the other day and to our surprise and horror there weren't any much difference in the tone.....
it's a doubling effect which accompanies a guitar with bass notes. if you activate it while playing a guitar, it gives you the illusion that there's a bass in the mix that plays exactly what you play.
if you think it's horrible, you probably have no use for it.