that would depend on how you build your box. size,wood used,and if ported or sealed and how many watts you run and how big your car is like when i had my crx i had 2 12 kicker solo x and a 2500 watt amp the box i had was loud and it had 4 ports i did a 148.8 on spl but when i got 3 12 solo x and 3 2500 watt amp i did a 150.2 but the box was bigger the 4 ports where on the right side and i used a different wood