Is 2500 watts too much for a x12? (critique my setup idea)

[sangean 10+ year member]

Gonna order that battery today. It takes 20 days to make but it looks like a good choice

Box is 39”wide by 21” high by 25” deep. Double baffle.

Volume is 8.76 ft^3 after speaker displacement. I’m going with a 10” quik tube port 30 hz

 

[hispls 5,000+ posts]

What battery specs actually matter?

Reserve (measured in amp hours AH) and C rating (which is a multiple of amp hours).

The specs those JY clowns post have the caveat right next to their ratings of "at 2C" or "at 1C" which means they're mix-matching maximum safe numbers with optimum and intended numbers depending on which makes their marketing hype look best. I could not get honest answers from any of those snake oil salesmen when I was battery shopping so I just bought my own cells from China and went the DIY route.

Anyway if you're planning a 300A alternator it will be trying to charge your batteries with 300A (probably not real world but safe to assume it may). Let's say you pick a 30AH battery with 10C charge rating that means the maximum current you can safely charge with is 10(the C rating) X 30 (the amp hour rating) or 300A. There is a big difference between the absolute maximum you can do before rapid or catastrophic failure and normal intended continuous use that will not dramatically shorten the life expectency of your battery and lead to poor performance.

Same story with discharge rating. Let's say your 10,000W rated amps will attempt to draw 1000A of current, even 100AH of 10C rated cells are working at their straight out max limit (though since AH ratings are at 1C you're not even doing that well) and both voltage and current capacity will drop extremely quickly under load.

In short, if you're coming out the gate trying to pinch pennies on a battery bank you're setting yourself up for failure from the start. If you can't afford a big battery bank you can't afford a 10,000W audio system period full stop.

From there Lincoln Town Car is one of the absolute worst vehicles to try to get sound up out of the trunk in. I did a 1980 towncar many many years ago and the build was costly and very labor intensive and it still wasn't anything special for how much stuff I had into it. I really love Lincolns but I would not consider an audio build in a car like this short of deleting the back seats and doing a B-pillar wall.

It seems like you are in way over your head here, trying to cram 10 pounds of **** into a 5 pound bag using a plastic spork. I would encourage you to go back to the drawing board on this whole project, otherwise what I foresee happening is you spending a lot of money on equipment but not enough to really do it right and winding up with something that is only good for creating the amount of trunk rattling that you could have bought from Best Buy for under a grand.

 

[sangean 10+ year member]

Thanks for clarifying all the ratings dude- The battery issue is the area where I am in over my head- I am gonna spend today learning about it. I'm not set on 10k- I'm ok with 7k rated watts.

If the alternator charges the battery faster than it's C rating, it will mess up the battery or shorten it's lifespan? I thought alternators were regulated for that. Or the battery wouldn't be able to take advantage of the alternators output.

Would you recommend adding an isolator for the lithium battery?

I hear you on the sound issue- The town car's seats don't fold down either, so I would have to remove the backseat (upright parts) to get more airflow. Check out this dude's system: He busted down the backseat. I hear you on the rattles- gonna turn it down when serving the trap.

 

[Popwarhomie 5,000+ posts]

Don't have to remove the seats. Just cut the rear deck.

 

[Kickstand Premium Member]

I would go back to the board with your box. Maybe its me but that box doesn't seem big enough for 4 12's.
The trunks on those town cars are huge so if you have the space use it
Slot port it like the one shown or do two round ports up through the existing speaker holes.
Please invest in some sound deadening, don't be that guy.

 

[sangean 10+ year member]

So I got lucky... My 370 amp alternator should be arriving by Sat evening, and I have some old equipment (1 x12 with kicker cxa1800.1) I can hook up in the time being. Plus I got 2 100 ah agm batteries that had been removed from a semi truck, so I’m gonna hook up a battery in the trunk that goes to the amp

Do any of you know off the top of your head where to ground the trunk battery in a town car (similar to crown Vic)?

I saw somewhere a guy drilled a self tapping screw into the frame rail

any tips on running wires? Am planning to run the main wire from front battery to rear underneath car, then find a way to sneak it into the trunk

 

[hispls 5,000+ posts]

If the alternator charges the battery faster than it's C rating, it will mess up the battery or shorten it's lifespan?

Yes. I was looking at some charts from my guy in China this morning. This is for a common """car audio""" cell
1C 30,000 cycles
3C 15,000 cycles
5C 8000 cycles
This is for 50C max rated cells, already we see at 1/10th of their max rating you are shortening their lifespan!

They do not go higher with published test data and who knows what this translates to real-world, but the conclusion is obvious, the harder you push these the sooner they will fail. I did not check for discharge graphs but if they're like any other battery I've seen performance also suffers as you push them beyond 1-5C

Over-charging is a very real risk, your alternator will try to give everything it has when loaded down and I would advise to delete the front/AGM battery entirely if you're going to start getting into Lithium as they will only hurt performance.

4th order bandpass porting up through the rear deck (like Pop's video) is your best option to get sound up front in a car like that but it is not a simple project and would be easy to **** up or make something that looked super ghetto. Shitcanning the back seats and doing a B-pillar wall would be an easier project IMO.

I also don't think 8 cube is quite enough to do 4 12s right and I suspect you won't have as much volume as you think you do, so might want to revisit that topic as well.

 

[sangean 10+ year member]

Got my stuff in the mail- the project is coming along nicely. I am ok with a box- I don't want to build a wall, but I am going to either dump the back seats or decklid. Before I worry about any more "bodywork" I want to make sure all of my electrical is good.


Got the amps in the mail. The speakers are coming tonight or tomorrow. I got a cold and wasn't able to run the second power wire this weekend, so I am shooting for tomorrow afternoon for the second power on tuesday. I still gotta cut the hole for the port- I was glad to see my form tube (10" quiktube) is on the big side- 10.25" inner diameter. Planning to cut it this weekend, then install the subs with box already in the trunk. I would need a crane to lift the whole thing in.

 

[shredder2]

Oops...
See below

 

[shredder2]

I still gotta cut the hole for the port- I was glad to see my form tube (10" quiktube) is on the big side- 10.25" inner diameter.

Just a fyi, and maybe I don't understand the install but with a 10.25" ID port I would keep it 15.5" long for min internal clearance. Quick and dirty that'll put you in the 35hz range but the proximity of the port entry to the bottom panel MIGHT just lower your tune a hair. I wouldn't go longer than 15.5" overall if it was me.

As stated above the volume you THINK you have may be a bit less than you actually have (and that will affect tuning), and the fact that your throwing it in a trunk, subs up/port up... I suppose looking for trunk lid flex. Just handicaps it from the get. Russian birch at 11/16" thick might buy you a bit more volume and be superior strength-wise but nobody wants to pay anymore.

Any bracing you'll add from here on out will raise tuning so keep that in mind. So stick to dowels and danger cut 45s if used.

 

[sangean 10+ year member]

Just a fyi, and maybe I don't understand the install but with a 10.25" ID port I would keep it 15.5" long for min internal clearance. Quick and dirty that'll put you in the 35hz range but the proximity of the port entry to the bottom panel MIGHT just lower your tune a hair. I wouldn't go longer than 15.5" overall if it was me.

As stated above the volume you THINK you have may be a bit less than you actually have (and that will affect tuning), and the fact that your throwing it in a trunk, subs up/port up... I suppose looking for trunk lid flex. Just handicaps it from the get. Russian birch at 11/16" thick might buy you a bit more volume and be superior strength-wise but nobody wants to pay anymore.

Any bracing you'll add from here on out will raise tuning so keep that in mind. So stick to dowels and danger cut 45s if used.

Thanks for the feedback dude

What do you mean by internal clearance? Like keep the port at 15” so it doesn’t go to far into the box.

Your calculations are close. The math I did has the port at 20” at 30 hz, but I didn’t subtract the port displacement from the quik tube. Do you subtract port displacement before calculating length.

i added 3 dowels that feel strong AF. You’re right about it taking space. Do you think I need to nail the baffle to the side boards? It’s already glued

 

[shredder2]

Your calculations are close.

My calculations are close?.. yay!

Your'e asking simple questions on here and come back knowing better?

Good luck and hope it all works out... jeez.

 

[sangean 10+ year member]

Did I offend you? I wanted you to clarify the clearance thing

 

[shredder2]

Did I offend you?

It did rub me wrong a bit. I actually sat down, crunched some numbers and gave solid advice. What I said I stand by regarding port length, clearance and volume.

The advice may help.

Good luck and hope it works out.

 

[20 hz bass machine Premium Member]

Lots of good info in this thread. Ill put my 2 cents in. I dont think you're gonna have any problems putting 2k to each sub. A sfb 13500 wired at 2 ohm after rise wouldn't put out 8k anyway. You're better off going with 2 full bridge amps wired at 1 ohm each or 1 half bridge korean wired at .5. I think you need more than 40 ah of lithium to support the amount of power you're trying to use. I built my own headway cells and saved a ton of money. I have 2 70 packs that I built for $2200. Id go the headway route if you're willing to build you're own cells. I think you're current box is ok but as others have said already, you're absolutely going to want to remove your rear seats. Either that or switch to a 4th order that ports through the rear deck. If you decide you want to build you're own cells or switch to a 4th order shoot me a private message and I'll help you out. You're on the right track. Best of luck with the build!