hi. i this is a problem of frequency of car... i have 4,500 watt rms of amplifier.. and for me not very loud...

i just install 3 batteries, 2 capacitor and have 3 subwoofer of 10"...

so isn't a problem of products or price... but i think the sound of car...

i can't explain very well. i don't speak english very well.

i want only to know if someone have make some change for best bass! for example poli fill or something similar.

thank you.