6th order questions

[Psi_optima12]

Hello everyone , I'm building m first wall and first 6th . currently in the process of building a 4 fi btl3 15's 6th order in my 1995 Chevy blazer 2 door v6. plan is to run 2 MD12k .5 ohm models wired at .5 on plenty of spim lithium ion 2 320 amp alts. besides tuning low which I'm tuning to 24-48 , hows a good way to peak lower? The whole purpose of this build is to be a decent windy and low demo build and I will very rarely play anything near 40hz. I know I need to buy a meter to test with and I already am planning to help but i just want to see what I could possibly do to peak on the low end

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[Buck 5,000+ posts]

I assume you mean series 6th order? I've designed a few of those haha. Do you know about 1/4 wave tuning, like how a t-line works? That can come into play with walls and peaks.

The best thing IMO would just start getting straight to box specs. So would need rear net airspace, tuning and port area, and front net airspace, tuning and port area. I mean to get low, you gotta tune low. If you don't want to play above 40 hz, may tune to 20/40. Depends on rear box size and port area, but I've done an Fi wall tuned to like 25/50 and it played all the way up to 65 hz or so but barely below 25 hz. Had small rear chamber and ports though and was a c-pillar.

This was that box, 2 Fi team 18's iirc.



And post up exact specs for your exact subs, too, that'll help.

Do you wanna get low and have range or just play from 20-40 hz only or? And I wouldn't necessarily shy away from clamshells either, just depends on space. What you're doing is going to be massive.

 

[Buck 5,000+ posts]

With 1/4 wave and tuning low, your vehicle is a resonator itself, like if you think about from your rear hatch or back of the box traveling front to the front windshield or dash, that itself is a port or t-line. You have a high pressure wavefront trying to resonate the distance of your vehicle. It depends on orientation, but say just viewing your vehicle with a ported box for those, the distance from the rear port opening to the front of the dash has 1/4 wave properties to it. Possibly with how short your vehicle may be, it could be advantageous to have the rear ports all the way at the rear of the vehicle to peak lower, too. With walls this big, you can more easily see how your entire vehicle is a single enclosure, including your cabin. You can actually measure from the back of the wall roughly to idk where you sit or front windshield/dash area to see what the vehicle might try to naturally resonate to, like if it was a transmission line.