The entire question does not register to me, sorry 'bout that...

If the voice you hear through the speakers sounds distorted, it will be harmonics from what is called "clipping" and may sound higher pitched than the fundamenal. Solid state amps clip very hard and will do so with the smallest amount of overdriving.

Tube PA amps are better, some are they are very forgiving about clipping and also have tons of "headroom".

I have made column speakers with four cheap 8" "stiff cone" speakers per box, all material ripped from a 4' X 8' sheet of 3/4" plywood.