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-   -   Ground pounder ideas (https://www.caraudioforumz.com/general-discussion-10/ground-pounder-ideas-206083/)

Lord Huggington 03-16-2010 08:00 PM

Ground pounder ideas
 
I measured the crap out of my car (01 Alero 4dr) to see what kind of crazy setups I could use. Which is cheaper and/or better? They're very different so of course I expect different results. I want to play music.

$125 each, 8 SSA DCON 12" on 2400w, SPL is 89, each in 1.220375 cf3 after displacement, upfire in the back seat (no modifying, just throw it in the back), box is sealed using .75" MDF or birch ply, double baffle but I'd rather keep it at 18" height, 25 x 50 x 18. I like this because I could easily take it out and use it in the house if 1.22 cubes per is okay, and it's not that heavy at 20lbs per sub (160+box). Almost no space between the subs and it seems like it would break without a really good baffle, is 1.5" mdf or .75" birch ply worthy? I lose the backseat and don't have to buy a bunch of power supply stuff.

$400 each, 2 SSA XCON 18" on 3500w, SPL is 91.5, each sealed in 5 cf3 after displacement (5.0-5.5ft^3 optimal) using 1" birch ply with resin/glue/screws with no double baffle, firing into the cabin from the trunk, the seat latch would have to come out and if the seat is upright than the subs can't be on or they'd hit and the seat can rest on them with passengers. I'd have to modify the trunk opening to 20" x 38" because stock it fits a square 17" x 26". I suppose I'd let a chassis shop muck with that. I don't think it'd sacrifice integrity of the chassis as it's not a lot of metal, just it's in the damn way, way to fk up Olds. There's space on the sides for 2 batteries & 1 under the hood for power. I wouldn't really have to seal it if the box takes up exactly 20 x 38 for a cheap "it fits here" seal. Box is 20 x 30 x 38.

2 Fi BTL 15" on 4-5k, spl is around 93, .75" birch or mdf, 4.0285 cf3 each, ported & foreward fire with the port inbetween, 15.49 vent per cube, .75"+.75" baffle, and no space between the woofer and the outside dimensions, it's exactly (38") 15.625 * 2 + 6.75" wide port. I used the RE calculator, it says 30.79hz. Box is 38w x 20h x 29.25+.75". If you put a port inbetween subs what happends when two opposite air flows hit eachother? Would I have to put something in & curve to aim the air or does it not really matter?

Is 1.5" MDF stronger than .75" birch ply? How much heavier is it? It's apparently twice the cost & twice the strength. Can you use MDF with birch ply? Thanks.

durka_durka 03-16-2010 08:23 PM

wall of 8 12s

fresh1 03-16-2010 09:09 PM

just a heads up.

Efficiency (1W/1m) is not an accurate indicator of a subwoofer's output capability and should not be used as a comparison to other subwoofers to determine which one is "louder".

thats from JL, so theres a good chance its right

BigRedGuy 03-16-2010 09:18 PM

I like the 8 12s as well, if only for the "Holy Crap.....:eek:" factor.....:D

You can also do more with box positioning if it's all inside the passenger compartment.....once it's in the trunk you're kind of stuck as far as moving it around goes.....:smokin:

Lord Huggington 03-17-2010 01:33 AM

I'll shoot for 8 12's because after fabricating the trunk, 3 batts, lotta wire, +4k power, and a huge alternator, it's too much money. I want it to slam 30-40hz. I like kick and tonal quality more than a raw distorted bass line, I don't like when I'm listening to a heavy bass line with kicks in the middle that I can't hear, it should punch me in the back of the head. What I'll do is keep the back seat in place and use a leatherboard to hide it below the windowline so it looks damn clean. I'm not doing a wall, I want to see out the back but I would of course tilt the box and throw in some cheap particle board around it to see what happends. The great thing is that I can open the door and easily take it out for when I go on long drives. I'm also not doing this if a ported 15" on the same power will eat it, just doesn't make sence. Any ideas on numbers @ frequency?

- What tune is 1.2 cf3 "optimal"?

- What are some other cheap 12's that I should look at?

- Without knowing the resonant frequency what airspace should I use to get the most output between 30 & 40hz? With cabin gain would I tune at 40 and expect 30+ to be near flat? How many hz below tune would the cones be at full 16mm excursion or at what frequency should they?

- If the rear seat is up would you consider the trunk to be sealed from the cabin? Would it perform like a hatchback?

- Does a quarter wave need more length to devlop higher SPL or is that only if it's not a wall? Walls are louder and usually closer to the front seats of any vehicle, so how would this do? Would it count as a wall if I faced them foreward and threw a piece of particle board around it, not really a quality seal but still blocking some air from moving front & back?

- I had 2 RF P1 300W, sealed 1.25 cf3 each sharing 550W and they were horrible for SQ & SPL but I paid about $60 each in 2006. I don't want this setup to be like having 8 of those, it would suck, so between what I've had in the past (05 XXX 12 & Eclipse SW8200 in the same ported box on 1500 & 750W @ 1ohm), can I expect the same sound quality or will I fear I bought 8 RF P1's?

- To find the res. freq. can I build multiple test boxes for one and have the same results when I throw in 7 more? Cabin gain would be different, so...

- Will the trunk flex at all? It's sooooo annoying to hear your awesome setup outside an undeadened trunk.

- Can someone model these in winisd or whatever?

•2"” wide, 4 layer, copper coils
•Push terminals
•Pulp Fiber Cone
•Dual NOMEX spiders
•FEA optimized motor
•2" Anodized alum. former
•Heavy Duty Lead wires
•Hand crafted in USA
•Fs 28.1hz
•Re 7.8
•Qms 4.46
•Qes .35
•Qts .33
•Mms 121g
•Xmax 16mm
•Vas 85.6
•Sd 480 cm^2
•BL 21.7
•SPL 89.1 1W/1m
•Wattage: 300wRMS
•Sealed: 1.20 cu.ft. optimal
•Sub Outside Dia.: 12.500”
•Cut Inside Dia.: 11.150”
•Mounting depth: 6.500”
•Displacement: 0.14 ft^3

Thanks.

thumpper 03-17-2010 01:55 AM

the 8 SSA Dcon 12" would be sick....they have really good SQ
and dig well on the lowest notes

Lord Huggington 03-17-2010 09:43 PM

I definetly want a sealed box. 2 Xcon 18's firing foreward from the trunk or 8 Dcon 12's upfire behind the front seats. If I use 25 x 50 I have to snip a piece of the door handles on the inside because it's about 49.8 wide and I have to ride with my front seat almost all the way up. Which do you think would score louder?

fresh1 03-17-2010 09:47 PM

you're definitely the first guy I've ever heard of who wanted a sealed box in a ground pounder

p.s. what amp(s) are you running this on?

durka_durka 03-17-2010 09:56 PM

ground pounder + sealed box = weak

DaVibe 03-17-2010 10:08 PM

Oh ... My ... God.

(Only because I own an Alero) ...

Yeeeeeeeeeee haw :D


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