Need some advice

[bump'n]

I am looking for some idea's on building a all out SPL box. I aready have a tuneing freq in mind of like 40 to 60 HZ. Now I am doing this in a reworked interior,there's no back seat,or any thing that look's like one , the rear deck of the car has been removed(back seat wasn't big enough,and would not allow front seat's to sit right) and the trunk is now sealed off from the rest of the car to make the car's cabin smaller,it's mow 6 feet 8 inches from back of cabin to fire wall. Now I will be useing 3 12's or maybe 4.with 6 amp's,maybe 8. I am looking for advice on where to fire the sub's,straight foward tward winshield,or fire up onto back glass. Then I would like to know if the port's should fire the same way as the sub's,I was thinking of useing aero port's, but they would be to long and hit the back glass. I have also heard that sub's foward and port's back is a good combo, but have no idea how that work's, as far a the sound wave's.

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[qtipextra 5,000+ posts]

In my experience, it has worked best when you have the port the same direction (on the same plane) as the subs.

You can use aero ports and have them inside the box, so they don't stick out. Or you do a slot port. Of course those suggestions will be for a permanent tuning, and wouldnt be interchangable.

On the firing question, the best rule to go buy is:

The more distance the sound has to travel before reaching the dash, the better.

So if you can have them facing back, and as far from the back as possible, then the sound goes clear to the back, and bounces back, to come clear back up to the dash.

 

[bump'n]

Wouldn't faceing the sub's back cost you SPL,because the sound would bounce instead of being forced to the dash forceing the sound to the dash. Could be wrong but seem's like they'd be louder foward(might sound like crap) in term's of SPL.

 

[qtipextra 5,000+ posts]

Bass waves get larger the further they travel.

 

[bump'n]

Don't you mean the wave's get lower (HZ). Yes,but what about standing wave's and cabin gain/cancelation.

 

[qtipextra 5,000+ posts]

Bass waves intensify the further they travel. This is correct. Learn to know that.

 

[bump'n]

Then are standing wave's not a issue when going for SPL ?

 

[PSturmer 10+ year member]

so then this would mean you want a big long port, causing the waves to travel farther?

 

[qtipextra 5,000+ posts]

Then are standing wave's not a issue when going for SPL ?

Standing waves can cause cancellation issues where applicible' date=' and can decrease SPL. In your situation, I don't see it being a problem.

so then this would mean you want a big long port, causing the waves to travel farther?

Port length affects tuning. It doesn't affect distance traveled.