Calling all box experts - is mine worth keeping?

[beezel]

I had a box made by the same guys who initially installed all my gear. They did not do a great job with wiring the amps, though neat and tidy it was far from optimal. This left me wondering about the box they made me.

I have one JL 12W6v1 (3ohm DVC) being pushed by a PG zx500.2 @3ohms. 12W6v1 has the following specs: http://mediacdn.jlaudio.com/media/mfg/9 ... 1317790304

Forgive my laymans terms, I'll do my best to describe the box.

It is a total of 36" long, by 15" tall, by 10" deep. Sub sits in the middle, in a chamber that is 12" long, 13.5" tall, and 6" deep. On both sides of this chamber are 2 other chambers that are 10.5 long by 13.5 tall and 6" deep. They are separated by MDF with 2 4"diameter holes into each chamber. The chamber on the right has a 2" hole in the "floor" that passes into the final bottom chamber, that runs the entire length of the box and is 2" deep and exits the left of the box. It is the full width and length of the box, 2" deep.

It doesn't sound terrible, but it seems to lack low end (an area i remember this system shinin in other cars) and doesn't seem to have the thump I remember. Does it seem decent? Or should I start looking for a replacement? Is it super weird to have a chamber on the left of the speaker that doesn't dump into the port?

I've done just an absolutely horrible job illustrating this on my picture. For reference, the RED is the exterior, the YELLOW is the main chamber width, and the BLUE should show the dual chambers. The RIGHT chamber has a 2" opening the width of it to a bottom chamber (GREEN) that runs the length of the box and exits the LEFT.

Thanks!!

[zztunnell]

Best I can figure is that chamber is really just a brace.

[todd217]

ok if im understanding correctly it has a single 2" hole that feeds into a slotted port that comes out the side? also have you tried plugging that 2" hole?

[beezel]

Best I can figure is that chamber is really just a brace.

That was my initial thought but the holes seemed a bit too restricted for it to be pure support. I could be wrong but to me they would either be by design or a flaw in design. Maybe someone with more experience can come in to their effect.

[beezel]

ok if im understanding correctly it has a single 2" hole that feeds into a slotted port that comes out the side? also have you tried plugging that 2" hole?

I tried the best I could to illustrate with green where the top chambers dump into the bottom port chamber. It is a 2" slot, not circle, that is as wide as the box. I couldn't get to it to plug if I tried. The top two side chambers are connected by 2 4" circles on each side. You can see one of them and a portion of the other on the inside of the left. Right chamber is identical other than the large slot in the floor, roughly illustrated in green next to the red 15.

Thanks

[todd217]

try plugging it from the outside with something you can pull out like some old shirts and run it as a sealed. it may be tuned too high where its loud but has no bottom end. but cut back on the gains trying to push 500+ to in in about 3 cuft sealed may damage the sub. if you now have the bottom end that your looking for plug it with spray foam. if its not loud enough try plugging the 4" holes on the side with the slot and turn up the gains slowly watching the excursion. the w6s are getting hard to find and will sound good and get loud.

[Kirghiz]

Best I can figure is that chamber is really just a brace.

Not the chambers, the partitions. The chambers themselves are part of the sub's enclosure since the partitions have holes to allow airflow. The partitions are there to brace the box and nothing more. There are certainly better ways to do that, 2" dowels would work better lol, but the way it's done should function alright. The box also features a 2" x 15" port that is what about 32-34" long?

Without putting the driver in winisd and modelling the box it's hard to tell, but that port seems a bit large, or at least long, to me for the size of that enclosure, which means it might be tuned wrong. I know a guy that built a box for an Audiopipe 15", screwed up his math and tuned the port to like 18hz. I had a single 10" sub ported to 35hz at the time, and it was louder at all frequencies.

My recommendation, rather than screw around with plugging things is to just go to Lowes, buy yourself some lumber, and build a new one.

[todd217]

or depending where you are at maybe one of us has a box that you can have. im in central il and have a 1.35ish sealed box that my idmax 12 was in id give you.

[zztunnell]

I got to thinking about that box.

It seemed like it was a lil shallow,so I punched it up on WIN ISD.

Sure enough,the box is a lil small,the ports a lil too long and it is shallow.

Using your measurements and the listed mounting depth of your sub.Im showing 3/8 of an inch from the bottom of the magnet to the inside surface.

Thats a lil tight.

I made my calculations assuming 3/4" MDF.

As it is (inside)34.5"w x 13.5"h x 6"d, with 2 3/4" thick braces and 2" x 13.5"w port 36" long.
I show 1.46cuft tuned@34.25. With a gain of 4.22db@58hz.

I found that a box of 3.14cuft tuned@33.55hz.Would give you a gain of 4.7db@43.8hz. And 3db down point @29.31hz.

This should put you smack in the ball park.

Pic shows your box in yellow and new box in orange.

Assuming 3/4"MDF and a sub disp. of .085cuft. Outside dimensions are 36"w x 15"h x 14.5"d. The port would be on one side of box exiting on the same box face as the sub and would be 2"w x 13.5"t(the height of box inside) x 14.5"long(depth of box+thickness of port wall.

[Kirghiz]

The port would be on one side of box exiting on the same box face as the sub and would be 2"w x 13.5"t(the height of box inside) x 14.5"long(depth of box+thickness of port wall.

That overall box looks more in line with what I was thinking. What would the vent air speed be with the vent length only 14.5 inches though? Shorter vents tend to have a higher air speed and end up whistling. That looks like the old version of winisd you're using. The newest version can calculate this.

[zztunnell]

It showed a (Vent mach) of .04 which in my experience is spot on.

Ive got Win ISD alpha but dont care for it.

[vwdude]

I had a box made by the same guys who initially installed all my gear. They did not do a great job with wiring the amps, though neat and tidy it was far from optimal. This left me wondering about the box they made me.

I have one JL 12W6v1 (3ohm DVC) being pushed by a PG zx500.2 @3ohms.







Thanks!!

How are you running a 3ohm DVD sub at 3 ohms? You should either have 1.5 ohms or 6 ohms.

I always liked these subs in a sealed box. Sorry that I didn't contribute to your exact question.

[zztunnell]

In response to your pm.

Outside 36"w x 9.5"h x 23"d. 3/4"MDF

Port 4"w x 8"h x 21.5"long. Tuned @32.59hz.
Located on side firing back towards trunk.

Gain of 4.34@43.99hz ,3db down@29.06hz. Vent mach of .03

White line is new box,orange the first one I did.

[beezel]

I had a box made by the same guys who initially installed all my gear. They did not do a great job with wiring the amps, though neat and tidy it was far from optimal. This left me wondering about the box they made me.

I have one JL 12W6v1 (3ohm DVC) being pushed by a PG zx500.2 @3ohms.







Thanks!!

How are you running a 3ohm DVD sub at 3 ohms? You should either have 1.5 ohms or 6 ohms.

I always liked these subs in a sealed box. Sorry that I didn't contribute to your exact question.

No worries, my initial statement was off. It's a 6ohm sub, final wiring leads to 3ohm. Wired in parallel. Series would give you 12ohm. As referenced here: http://mediacdn.jlaudio.com/media/mfg/9 ... 1317790304

[beezel]

In response to your pm.

Outside 36"w x 9.5"h x 23"d. 3/4"MDF

Port 4"w x 8"h x 21.5"long. Tuned @32.59hz.
Located on side firing back towards trunk.

Gain of 4.34@43.99hz ,3db down@29.06hz. Vent mach of .03

White line is new box,orange the first one I did.

Awesome! Thank you very much, this helps tremendously.