inputs.text: husband loves sub amplots bass - bought mtx subs amp husbandfirst day installed bass really loud couple hours amplifier thermal switch kicked shut amplifierso husband called mtx said bring amp internal cooling fan upgradenext day took amp mtx manufacturer phoenixaz techs great installed internal cooling fan inside amplifier drilled factory vent holes sides amplifiermy husband happy techs mtx fixed problehemhe reinstalled amplifier parking lot mtx never overheated thermal switch not turned ona big thanks goes techs mtx fixing problehemthey added cooling fan beginninganyhow gave 5 stars thats mtx installed internal cooling fan