Subwoofers hitting very weak, how to increase?

I have a 2015 Honda civic that I just installed my Sony amp and alpine 10"s with a stock head unit. The amp is on the subs are on but the bass is very light. The stock radio doesn t allow me to control the bass, and the amp doesn t have any knobs on it to control. I d rather not buy a new radio and instal it.

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