Need Help With New BTL 18!!!

[bigbud747 10+ year member]

I'm getting ready to put a new style BTL 18 in an extended cab ranger. He'll be running it off a Memphis 4K (electrical will be upgraded before I even install it.). This kid loves the lows but also wants to do a 150 or maybe better. I was planning on doing a box around 6~7 cubes, with 120~150 square tuned to 32 hz. How do these specs sound for his recommendations? I really want peoples opinion on this because I've never worked with a BTL so I don't really know what sounds good, where it gets low at, or what volume I need.

Oh, and would it be worth it to do a kerfed box, or would that just be a p.i.t.a when it's all said and done?

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[Diplexers 10+ year member]

I'm getting ready to put a new style BTL 18 in an extended cab ranger. He'll be running it off a Memphis 4K (electrical will be upgraded before I even install it.). This kid loves the lows but also wants to do a 150 or maybe better. I was planning on doing a box around 6~7 cubes, with 120~150 square tuned to 32 hz. How do these specs sound for his recommendations? I really want peoples opinion on this because I've never worked with a BTL so I don't really know what sounds good, where it gets low at, or what volume I need.
Oh, and would it be worth it to do a kerfed box, or would that just be a p.i.t.a when it's all said and done?

I've got my new style 12" BTL tuned at 31.5 hz and the lows are awesome. No experience with 18"s though. Did you check the enclosure thread on SSA? They list the recommended volume and port tuning.

 

[bigbud747 10+ year member]

Yes. I've checked the site and I've got a lot of experience with the Bl 12 and 18 inch versions. It's just since I've never had a BTL I don't know really what to expect. The Bl 18's I had installed in 9.5 cubes with 140 inches of port tuned to 34 hz and they did alright on the low but really shined about 40hz and up. I really want to make this new box for the BTL shine in the lows though. That's why I need to know what people have had good success with as in port area for their BTL's, and tuning frequency.

And I was throwing around the idea of making something like a 10 or 12" port (using my school's CNC machine to make perfect mdf rings so that wouldn't be a problem, and I followed the build that one guy had that made a 10" port with mdf rings), or if I should just go slot ported with about 100-150 square inches?

 

[mlstrass 5,000+ posts]

might want to consider doing an SPL and daily port for the box...

 

[bigbud747 10+ year member]

I've talked to the guy and here's what we've come up with:

- Box about 14 inches deep.

- All the way to the window line.

- Sub in the middle of the box facing forward.

- A slot port on each side totalling about 120 square inches.

- Amp (Memphis 4k) flush mounted on the top of the box where only about 1/4" will be sticking out, and all wire hidden in the small flush mount box where the amp is mounted.

- Tuning at 30hz

- All carpeted in Medium Gray felt (we work at a carpet store and this stuff is what I use on all my boxes and is soft as hell).

I'm open to all opinions on what I could change or what would make this look or sound better.

 

[galacticmonkey 5,000+ posts]

With 4k on the sub, you want a smaller box with less port. Try around 6 cubic feet with 80 square inches of port.

7 Cubic feet with that much port area will have the sub smelly in no time. You would be reconing all the time. Been there, done that. Not fun.

 

[bigbud747 10+ year member]

That's exactly what I needed to know. I knew that less volume would equal more handling power, but I didn't know how little volume to use. Just to be safe I've gonna probably do 5.5 cubes with about 90 inches of port.. Does that sound alright to you galactic?

And btw, do you have any new videos of your express van? That thing is just sick. Haha. Or are you waiting on some new SAZ3500's?

 

[galacticmonkey 5,000+ posts]

I wouldnt even use that much port, personally. 75-80 would be just fine and still give the sub the back pressure it needs.

Does he already have the sub? If he doesnt, and feels like spending a bit more for better results, 2 15" BTLs would work alot better with that power.

 

[bigbud747 10+ year member]

Well, here's the deal. This is the same kid that has the ranger that I built with 2 18's walled off in that white extended cab ranger. Well, now he wants to see out of the back glass again so he's tired of the wall. But, he still wants to be as loud as he was, but be under the window line this time. He wanted to just go with 1 18 to run off that 4k because we could sqeeze a box under the window and have enough room for one. He also had his mind set on a BTL, but if there is another 18 out there that would possibly be better, and be able to get it the same or cheaper as a new BTL ($500), then that would be great.

Or, if we could fit 2 15's under the window line, and be just as loud as he is now then that would be even better so the power would be distributed through 2 subs and not just one. He's hitting around a 150 at 44hz the way it is now with each sub getting about 850 watts off a Hifonics BXI2608 (He's actually listing everything in the classifieds right now). But, I would also want to build a box that will completely smash the lows, while still getting up close to 150.

 

[galacticmonkey 5,000+ posts]

Will definately be a challenge to do that and keep the rear view open.

 

[bigbud747 10+ year member]

The box I've got in there now is 9.5 cubes and goes about half way up the window line. I was originally thinking about suggesting a soundstream xxx 15, but I've heard you have to be careful with the power on them or they'll blow. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif That would be bad ass to do just one 15 facing up in that truck. Haha.

 

[galacticmonkey 5,000+ posts]

A single 15 below the window line wont keep up with 2 18s through the rear window. More space to pressurize and less than half the cone area to do it.

 

[15nissen 10+ year member]

might want to consider doing an SPL and daily port for the box...

Or aero ports.

Just plug a port or 2 to tune higher.

 

[bigbud747 10+ year member]

A single 15 below the window line wont keep up with 2 18s through the rear window. More space to pressurize and less than half the cone area to do it.

Yeah. I was thinking that, but it's always nice to have a rear glass. I'll probably try to make a box for a single BTL 18, firing forward, with a square port that's interchangeable between one that's tuned to 30hz, and one tuned to like 50-55hz. Where it could beat the hell out of the lows when cruising town, but when's it's comp time switch it to the comp tune, and hit the high number. How does that sound?

And all this below the window line. I would really appreciate pictures of peoples extended cab ranger builds to just get a better idea of design.

 

[galacticmonkey 5,000+ posts]

For daily, use a smaller port, around 75 square inches tuned to 28-30hz or so.

For metering, make a port piece that has a bigger hole, around 110 square inches tuned to 40-45hz or so.