Loosely sealed sub enclosure?

[pattyweb 10+ year member]

I'm trying to build a sub enclosure into the back right quarter area of my SUV. I use the third row a lot and can't afford a big box. And there's a rear most flip up that I don't want a small box sitting on top of.

The rear right quarter has a big door panel for accessing the tail lights and a bottom trapezodial piece that comes out for getting into the space below the rear deck. I've fashioned a front/top face for the sub enclosure that fits nice and tight into that back corner against the plastic trip and rear wheel well. The face completely covers those openings so the space behind those would be a part of the 'box'. In total, I think I'm at around 1cuft. As far as I can see, everything is pretty well sealed except for some vents along the top of the right side trim near the rear right window. So some of the sound wave/pressure will work it's way there. It's possible I could stuff that space so that it's not as connected but not sure how well that would be.

Should I be worried? Obvisouly, it won't be 100% sealed. More like a very badly ported box? Considering I have no sub at all right now, I'm hoping it overall will still represent an improvement in sound quality.

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[86yota 10+ year member]

Um, it will probally sound like junk, and no where near a bad ported box. Ive had minor air leaks on sealed boxes and hated it.

 

[pattyweb 10+ year member]

Well, I could always enclose the back of the top part, not make use of the space behind the tailight access door and just extend the box down and make use of the space completely underneath the back end behind the bumper. I'd have to seal it well for moisture, etc.

Is there a general rule on how to connect various volumes without the 'connection' parts becoming 'ported vents' for the primary volume space behind the speaker?

 

[Chriscivic 10+ year member]

Get a sub that can run free air

 

[swimfreak26 10+ year member]

There is no special "trick" for connecting volumes of air. Ensure the entire thing is sealed and that the net volume is that which you desire, no magic or anything of the sort, just a bit of math, good construction skills and some silicone.

 

[imaspaceguy90 10+ year member]

seal it, else it will just sound like diahrea, but good thinking on that spair space man, GL!

 

[helotaxi 5,000+ posts]

Unless there is a way for the air to move between the enclosure and the car, the air inside the box is all that matters. Unless there is a really constrictive space (only a couple square inches) the entire air volume will compress and rarify as one. One of the beauties of a sealed enclosure is that you don't have to have X amount of cross section through the entire enclosure or even have the volume exact. As long as the final volume is within a few percent of the desired volume it will sound almost exactly the same.

 

[pattyweb 10+ year member]

Thanks! I get get about .4 cuft inside and maybe another .6 outside down below the top part. I'd need to connect the two volumes with a piece of pvc pipe maybe 4" by 8". I just can't help but think that somehow that pipe would act like a vent between the two volume spaces. If it really doesn't matter, I can get access to more space but I'd need an elbow joint in the pipe connecting the spaces.

 

[helotaxi 5,000+ posts]

I just can't help but think that somehow that pipe would act like a vent between the two volume spaces. If it really doesn't matter, I can get access to more space but I'd need an elbow joint in the pipe connecting the spaces.

Since air is not flowing in/out of the box, that will be more than big enough to keep it from compressing in the passage. The whole thing will act as a single air space, no problems.