Box design.....HELP M3 8's o. 1.2K

[Kerry.davis]

Just finished installing a DC 1.2K running (2) M3 8's.....threw the subs in a quick sealed .75 cube each enclosure....holy hell,  it sounded BAD....I KNOW I SCREWED UP using a sealed box, was in a hurry to get them running,  so here I am needing enclosure design help.  It's in a 2015 Honda Accord EX-L sedan. I'm very handy,  can make me own enclosures, have done so many times. I'm an old school audio junkie from way back,  just getting back in,  used to use a ton of the old school,  American made RF power equipment back in the day,  now switched to DC.....again please help......i can answer any questions to help