# Sub Clearance to Bottom of Box (mounting depth)



## alligatorman (Sep 7, 2010)

I was talking to an installer today and he said a minimum of 1.5" for the magnet-vented subs. He said this space is required for the speaker to sound clean.

Anyone heard of this rule of thumb before?

I'm trying to mount a 5.9" deep sub in a 6.5" deep box. lol....


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## azngotskills (Feb 24, 2006)

does the subwoofer have a vented pole piece?


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## alligatorman (Sep 7, 2010)

I would say yes.

Ultimo SC 12
http://www.morelhifi.com/support/pdf/mobile/Ultimo Manual.pdf


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## boogeyman (Jul 1, 2008)

I have always went by the rule of thumb. The min. allowable dimension from the vented pole piece to an enclosure wall or port is equal to the diameter of the vented pole piece.


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## jcollin76 (Oct 26, 2010)

boogeyman said:


> I have always went by the rule of thumb. The min. allowable dimension from the vented pole piece to an enclosure wall or port is equal to the diameter of the vented pole piece.


^^^This is what I have always gone by.


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## alligatorman (Sep 7, 2010)

jcollin76 said:


> ^^^This is what I have always gone by.


Well I know for a fact that you couldn't have followed that rule with your truck for those DIYMA 12s unless you put them in the bed.

I have the same truck. 2011 GMC CCSB 1 ton.

Would you care to share any specs of your enclosure?

I'm buying the subthump sealed unit. 

Considering what you guys are saying, I should be looking at the JL 13TW5-3 or Alpine SWR-T12 (or other shallow mount sub).


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## jcollin76 (Oct 26, 2010)

alligatorman said:


> Well I know for a fact that you couldn't have followed that rule with your truck for those DIYMA 12s unless you put them in the bed.
> 
> I have the same truck. 2011 GMC CCSB 1 ton.
> 
> ...


Sure... I raised my rear seat 3 inches. So in fact, I did.


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## alligatorman (Sep 7, 2010)

Hahaha cheater!

Well done I will look into that.


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## jcollin76 (Oct 26, 2010)

Cheating?! Lol I like to think of it as doing what ya gotta do.
You know all too well there isn't crap for extra room under, or behind those seats.

I used 3" steel C channel. Had it cut in 2-3" sections, then drilled them to match the mounting locations of the seats. 
Then You just have to source hardware to mount the seats. 

It was a PITA getting it to all line up, but worth it. Opened up a lot more options for enclosures.


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## alligatorman (Sep 7, 2010)

Great idea I like the way you think!

One thing though, is it skirt-friendly? 

I think I'll just go trade the Ultimo SC for a JL 13TW5-3 shallow mount and be done with it.

Thanks for the advice and info on the seat lift. I will consider that mod if this JL doesn't do it for me.


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## jcollin76 (Oct 26, 2010)

Lol I don't see why not, but I only let the kids back there anymore.

Kinda a tight fit for the oldest though... He's 15 and 6'6". Lol


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## alligatorman (Sep 7, 2010)

The best option as far as enclosure size and mounting depth is the Polk MM1240. Are these any good for sql?

They're cheap and can take some power and they're only 4.7" deep. So I would have nearly 2" clearance. That should be enough, right?


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## boogeyman (Jul 1, 2008)

2 inches will be plenty of room


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