F150Matt 10+ year member
Senior VIP Member
I have a friend with an extra cab GMC Z71. He recently purchased two of the Diamond Audio M3 12'' subs. He wants to mount them underneath his rear seat. I believe there is about 7-8'' of height under the seat. I was planning on firing them downward at the floor. How much space should I leave betweenthe floor and the woofer? I was thinking 1 and a half inches would be plenty but I've never built this type of box before. ALSO, does anyone have experience with porting these M3 woofers? I may not be able to get the airspace, but if possible I would like to port this enclosure. Diamond recommends a round port of 4''diameter with a depth of 13''. I would like to go with a slot port instead of the round ports and build it into the center of the box firing forward toward the front of the truck...Then the port could actually be used for bracing in the center of the box. Let me know what you guys think. I should have some measurements on the space I have to work with this afternoon. Thanks. Hopefully I'll make enough money off of building this box for the guy to fix my orion amp!