nasty sound distorsion

[alski]

whats causing sound distorsion?
alpine head unit 4 x 45w + ipod interface
through pioneers to front [ lots of dyno mat ] and oem rears

alpine gives nice sound to 20 on the dial
20-25 a bit rough
25-35 bloody awfull

even if volume all put to fronts

its only been an issue lately as had to crank up the volume to fight manifold/exhaust
back ground noise, during sunny days, with windows down etc

not after a max power ice install

do i have to amp? to get a cleaner sound?

sorry not got box to hand of pioneers, but they were yellow kevlar " mid range cost wise"
if that helps

[MINI-Morgan]

When you turn the bass down does it get better?? More than likely the head isnt powerful enough to power the new front speakers. I run factory head unit and speakers with a line filter and 12" sub in the boot. Bass set to low and actually sounds really crisp to me. The standard speakers arent too bad