Hello.

I've got a BTL 12, the new model, with the spl gap, short coil and cooling and I'm looking for some ideas on a box volume I can use for burps and keep it mechanically safe.

I had an old 1.3cf box laying around so I used that for some quick testing. The highest score with all testing was only 147dB on 3600w clamped watts. The actual power to the woofer will be a bit over 4000w once I get good battery.

The goal is to score 150dB out of this single 12 and the small box is 3dB short.

This is how the 1.3cf box looked at the end of the testing:

I also tried all combinations of sub / port facing except both of them back.

A max volume suggestion would be useful as I can cut down the box untill I find something optimal for my setup.

i would probably just stick to the max recommended by fi...but i dont compete so idk how much bigger u can go.

2.5cf should be a bit better than the tiny box I'm using now. If I can't get other ideas I'll just go for that size.

Somebody has to use btl's in spl setups

1 got a btl 15 in a 10 cube sixth order go as big as recamended from fi or a lil more but the bigger the more efficient it will be and you should be safe even with that kinda power i'm that big of a box and run a saz 3500 at half ohm for competition

Edited March 8, 201015 yr by K2rush7

Well, it's settled then

I'll build a 2.8cf box and see how my efficiency climbs.

Curious to see what kind of gain I get if I increase the port area, going from a 6 inch aero to an 8 inch one.

Did a quick box build, 2.1cf so we can keep it in the cargo area and got to testing with a BTL 12 which had the long coil.

Different car, peak freq and electrical but we got some good scores. Stock Z1 (which didn't like clipping from the stock HU) scored 149.6 @ 42hz.

Back seat was down when burping.

Next week, 2.8cf box in the Jeep

How come all the burp boxes I see have aeros on the outside, never slot ports or internal aeros?

Is it just for ease of port length adjustments or something else?

Good luck with future testing!

Much easier to adjust the tuning with the external port. For me that has been the main reason for external.

Round vs slot ports, some swear by round ports. Which are also easier to flare. I've seen solid gains from flares only.

Much easier to adjust the tuning with the external port. For me that has been the main reason for external.

Round vs slot ports, some swear by round ports. Which are also easier to flare. I've seen solid gains from flares only.

Coolio.

Good luck with the jeep box next week.

Keep us informed with what results you get! Always like seeing SPL results with a single woofer!

Update :

2.8cf box, 8inch aero done.

Efficiency is the same as the previous car but having a crappy battery drags me down a lot. 145.3 with 900w and 148.9 at full boogie, engine off and 1 800cca starter in the back. So still 1.1dB under the goal.

Box moves a lot during burps, time for some bracing.

very nice numbers!! looks like i will have some competition with my single 12" BTL. lol. im not building for competition tho.

Thanks !

The odds of me competing against you at the same event are...slim

Unless I make the 6000 mi trip.

PM'd you a box calculation I had laying around for wuite a while now , not going to use it . should do numbers .

Thanks

and you have pm back

Thanks !

The odds of me competing against you at the same event are...slim

Unless I make the 6000 mi trip.

From "where Dracula lived" and drank the blood of peasants and stole their car audio gear!

Good job so far, 150db on the way for certain!

Getting closer !

149.3 with 3 batteries.

Interestingly enough with a threaded rod as a brace I lost score.

I still have work to do on the enclosure if I am to reach the 150 goal with only 2 batteries.

How did I miss this another 1 12" wonder. I'm tuned in!

It's no wonder by any means, really

Need to test sub up port back and them doubleing up panels.

you not gonna build my suggestion ?

I'm going to build it for sure, I promise !

Testing a different port / sub orientation was easy to do with my schedule.

Sub up / port back scored 149.3, engine off, 2 batteries. Old speaker hole was just blocked off by a panel. Today I added a second baffle and replaced plugged panel with a good panel. Score dropped to 149.0. Hoping it's because the batteries weren't charged good. Having a smoother panel and a stronger baffle can't be bad

Why are you always testing with engine off? Is it part of your comp requirements? And so you just use the same box everytime and just tape the panels in? Some damn good taping though! GL with hitting the 150! definitely a great accomplishment with a single 12!

Yep, some formats require engine off. For the others the score won't go down with the engine on

I modified the old box, wouldn't be too fun to build a new box every time I want to change something. Also had everything glued together about an hour before testing.

Had to flush mount to get it under the window line :

New rear panel, not having this cured probably caused the drop in score

man that is a AWESOME score with just 1 12"

i know of ppl who struggle to do that with 2\3\4 subs

spl is such a funny thing so with some tweaking i know u will hit that 150 soon

Edited April 3, 201015 yr by SPL_Man