# subwoofer front clearance



## King Nothing (Oct 10, 2005)

How much clearance does a subwoofer in a ported box need on the front? Im wirking with a space approximately the size of the behind the seat area of a regular cab truck and trying to calculate box dimensions


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## mikey7182 (Jan 16, 2008)

What's the xmax on your sub? You'll want a good few inches of clearance if you have the room. Fire the port to the side.


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## King Nothing (Oct 10, 2005)

I wasnt worried about the sub physically hitting the seat, just the acoustic effects of having it "too close. The port will be firing upwards


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## quality_sound (Dec 25, 2005)

As long as the sub doesn't hit the seat you're good. Also, ideally the port will be on the same side as the sub, but realistically, put it where it fits.


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## King Nothing (Oct 10, 2005)

quality_sound said:


> As long as the sub doesn't hit the seat you're good. Also, ideally the port will be on the same side as the sub, but realistically, put it where it fits.


Would it be better to do a straight port firing up or a port with a bend firing the same direction as the sub? this will be my first ported box after running sealed for the last 10 years


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## A8AWD (Mar 6, 2008)

King Nothing said:


> Would it be better to do a straight port firing up or a port with a bend firing the same direction as the sub? this will be my first ported box after running sealed for the last 10 years


Same direction as the sub...but that is where you need to watch your spacing...basically if you have a 2"x12" slot port and only kept the sub 2" from a surface, you would actually be adding more length to your port...if it was a 2" port keep it 3"-4" away from the surface.

"Put it where it fits" is good advice when space is at a premium and you already have your equipment...


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## King Nothing (Oct 10, 2005)

A8AWD said:


> Same direction as the sub...but that is where you need to watch your spacing...basically if you have a 2"x12" slot port and only kept the sub 2" from a surface, you would actually be adding more length to your port...if it was a 2" port keep it 3"-4" away from the surface.


Are you saying that the port being close to the rear of the seats would make it seem like adding length to the port? Is this because of the restricted airflow between the box and the seats?


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## A8AWD (Mar 6, 2008)

The port length would technically be lengthened if you were to build the box the width of the xcab and fired it backwards close to the rear wall...

You should be ok firing it into the seat. Are the seats cloth or leather?


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## King Nothing (Oct 10, 2005)

A8AWD said:


> The port length would technically be lengthened if you were to build the box the width of the xcab and fired it backwards close to the rear wall...
> 
> You should be ok firing it into the seat. Are the seats cloth or leather?


lether, but the back of the seats is a hard, carpet covered cargo floor. BCAE1.com said I neede a port appx. 7 inches long and 3 inches diameter. it could basically go anywhere if thats the case. a 2x12 slot port sounds HUGE. forgive my ignorance on ported enclosures, Im trying to learn


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## A8AWD (Mar 6, 2008)

Slots are big, but are less turbulent that a round port. Just convert the cycinder to a slot....3.1416 x r squared x L...so with a 3"d x 7" l round port you could get away with a nice small slot port...

Here is an example. This kid does some quality work:

http://www.diymobileaudio.com/forum/showthread.php?t=34019


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## tcguy85 (Oct 29, 2007)

A8AWD said:


> *Slots are big, but are less turbulent that a round port.* Just convert the cycinder to a slot....3.1416 x r squared x L...so with a 3"d x 7" l round port you could get away with a nice small slot port...
> 
> Here is an example. This kid does some quality work:
> 
> http://www.diymobileaudio.com/forum/showthread.php?t=34019


are you sure you don't have that backwards?

a round port with a flare on each end won't have much turbulence. that i know. i always read you can get away with less port area if you are going to use a round port.


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## A8AWD (Mar 6, 2008)

Actually I haven't read anything on this topic...just going by experience.

Isn't that why they came out with that "aeroport" thingamajiggy....to reduce round port turbulence?

I'm a sealed/IB guy, but when it comes to ports I always stick to slots with nice radiudes corners throughout the port length and at the port mouth.


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## A8AWD (Mar 6, 2008)

tcguy85 said:


> are you sure you don't have that backwards?
> 
> a round port with a flare on each end won't have much turbulence. that i know. i always read you can get away with less port area if you are going to use a round port.



Also port area is port area regardless of the shape...

Someone please correct me if I am wrong. I hope I haven't messing sh!t up over all these years


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## King Nothing (Oct 10, 2005)

I think in this instance, since it will be my first try at a ported enclosure, Ill fire the port upwards so I can just use a straight port with no bends etc


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## tcguy85 (Oct 29, 2007)

A8AWD said:


> Also port area is port area regardless of the shape...
> 
> Someone please correct me if I am wrong. I hope I haven't messing sh!t up over all these years


i'm not sure the science behind it, but i have read numerous times that you can use less port area if you use a round port, especially if you can do a flare on each end.

anyhow, i use a 3" port with a flare on each end on my ten and it works very well.


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## ClinesSelect (Apr 16, 2006)

If you get bored, build one enclosure with the port facing up and then build another one with the port facing the passenger side, assuming there is some room between the enclosure and the side of the truck, and compare the output of the two.


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## Oliver (Jun 25, 2007)

ClinesSelect said:


> If you get bored, build one enclosure with the port facing up and then build another one with the port facing the passenger side, assuming there is some room between the enclosure and the side of the truck, and compare the output of the two.


And there it is ^^^

Passive Radiator fired towards side for the win !!


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