no, but it would significantly reduce output. if your amp does 200w x 1 @ 4ohm, and you put an 8 ohm load on it, it would probably cut that rating in half.
input sensitivity is probably set too high. that's distortion and clipping causing that noise, or feedback.. same end result. turn down the 'gain' you can't use gain to compensate for having a weak amplifier or a sub with too high of a load to get good power from the amp