I sized my subwoofer box using https://subbox.pro/en/ https://subbox.pro/en/ . I built the foam board speakers the same way built here https://www.youtube.com/w

I sized my subwoofer box using https://subbox.pro/en/ https://subbox.pro/en/ . I built the foam board speakers the same way built here https://www.youtube.com/watch?v=CKIye4RZ-5k&ab_channel=TechIngredients https://www.youtube.com/watch?v=CKIye4RZ-5k&ab_channel=TechI... . The amplifier is a class D amp from amazon somewhat like this one https://a.co/d/8XgEEsG https://a.co/d/8XgEEsG