Enclosure Questions

[JustinStone]

Couple questions about Enclosures

Is there a downside to extending the port outside of the enclosure?

How much airspace should be left between the subwoofer and a wall of the car? The edge of the box design I have planned will be close to the hatch, creating a very small separation that air can flow from (about an inch away) and I'm concerned this could restrict the cone movement on the woofer and consume power.

Rough sketch; the actual plan will be in autocad, and reflect the answers in this forum.

Lastly, I see many enclosures screwed to the bottom of the trunk via wood lining or other means. Is this a security feature or functional in creating a more solid enclosure by not allowing it to move?

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[Buck 5,000+ posts]

You don't want the port firing into a different cabin space than the sub. If you fire the port like it is in the pic, and have the sub sort of closed off in the trunk, you may get cancellation issues. I may not be understanding what you're doing entirely, either. Subs can be close to the wall of a car- ports have to be a little further away, from my experience. My point is that you don't want the sub and the port pressurizing two different areas. For example, you don't want the subs pressurizing the trunk, with the port pressurizing the cabin. Do you have a ski hole or rear deck or what vehicle are we talking about?

 

[JustinStone]

You don't want the port firing into a different cabin space than the sub. If you fire the port like it is in the pic, and have the sub sort of closed off in the trunk, you may get cancellation issues. I may not be understanding what you're doing entirely, either. Subs can be close to the wall of a car- ports have to be a little further away, from my experience. My point is that you don't want the sub and the port pressurizing two different areas. For example, you don't want the subs pressurizing the trunk, with the port pressurizing the cabin. Do you have a ski hole or rear deck or what vehicle are we talking about?

I have a rear deck. A Pt cruiser. My main concern about this setup is the issue you describe. I need my subs to fire in the direction of the decklid, yet have a long enough port for 20hz. The top corner of the enclosure is very close to the interior panel of the deck, and might cause pressurization issues.

Forgive the budget dimensioning materials, I needed a way to visualize my idea. Nevertheless, the subwoofers will be almost completely sealed off from the back of the deck, and I fear this will create problems.

This is the design I had in mind, but there is only ~0.5" of pole hole breathability, so I went to traverse the external port route.

 

[AnthonyO 10+ year member]

When I did this in my old setup in a VW Golf. I fired the subs forward and port firing to the drivers side. I had about 3" of space from the port to the side of car. Sounded amazing, no cancellation and got loud.

 

[2RZ-FE 10+ year member]

I have a trunk with back seats that fold down. My sub sounds better firing back positioned between the strut towers compared to a few inches away from the back. I used 3/4 mdf to cover most of the trunk floor.

 

[Buck 5,000+ posts]

What size sub do you have? Could you not fire everything up?

 

[JustinStone]

What size sub do you have? Could you not fire everything up?

I've gone through a couple designs like that, but I only have 11.5" of space between the top of the seats and the hatch. Any design I tried would have to have diagonally positioned subs for 12". Oh, my subs are 12".

This was the old design; the port was far too large and the, and the back of the box would again.. not have enough pole vent breathability. Although, to be fair it was 4 months ago and I had no idea about ports taking up box space.

These are for 10" DD redline 700's

I was thinking about just going buying 10's so I could remove the difficulty... but I have 12's and solving the issue with some thinking will save me $350.

 

[Buck 5,000+ posts]

I think that first box would work. That's quite a large port, from the looks of it.

 

[Buck 5,000+ posts]

Just make sure it's not too close to the hatch, which I why I assume you have the port recessed?

 

[JustinStone]

Just make sure it's not too close to the hatch, which I why I assume you have the port recessed?

Hey, returning to this thread with the issues in mind resolved to my knowledge.

the same area is pressurized, and the port is 8-10in away from the hatch.

Are there things I can do to improve this design?

 

[Buck 5,000+ posts]

I would make the port more square, it's too skinny. Max away from the hatch you usually need is 6"

 

[JustinStone]

I would make the port more square, it's too skinny. Max away from the hatch you usually need is 6"

I'll try to redesign the port

 

[JustinStone]

I would make the port more square, it's too skinny. Max away from the hatch you usually need is 6"

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