Ported Diamond Audio M3's

[F150Matt 10+ year 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!

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[ramos 5,000+ posts]

Let's see the M3's are awesome in a ported enclosure. I put a pair in a honda accord a couple of weeks ago. They get really loud, and sound great too. As for how much space to leave. Make sure to leave enough room for the sub to reach full stroke and a little bit of breathing room ( probably around an inch - inch and a half ) and you will be good to go. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[F150Matt 10+ year member]

WEll now after seeing that I wont be able to get the airspace to go ported, do they sound ok in sealed? And will .85 or so ft^3 be enough? Diamond recommends between .6 and 1.2ft^3. Theres less room to play with than I originally thought under that seat.

 

[F150Matt 10+ year member]

But if they may not sound so great I dont want to mess with it, because I know this guy would blame me for it. Although any box that was completely sealed up would be better than the piece of crap he has them in now. Do you guys think that 150$ is reasonable for me to charge him to build a box for 2 12's under the rear seat in an extra cab chevy? I may have to fiberglass some too and if I do I may ask 200$. Guy said that every shop around here wanted at least 250-300 so I'm well under what the shops want. Reasonable or not? I dont anyone to think I"m ripping him off. BTW the Q-logic prefab boxes (.65ft^3 each) are 250$ each...so compared to that I think my friend will be getting a great deal.

 

[ramos 5,000+ posts]

That should be enough room. Stuff some polyfill in the box. This is one of the only times you will here me suggest polyfill. But in your case with such a small enclosure it might actually help //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif