need some help on precision ports

[Jason19 10+ year member]

alright so im gonna make a box for 2 12 inch type r subs gonna run anywhere between 1000 and 1500 watts and I wanna use precision ports Im gonna make the box 27 x 27 x 14 which should be around 4 cubes and I want it tuned low around 28hz and wanna use 4 4" precision ports and was wondering how long each port would have to be any help would be great thanks.

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[miker 5,000+ posts]

That would be 40" each.

 

[CRXBMPN 5,000+ posts]

i'd use three 4" aero's for that sized box or else they are going to have to be long, or you will be tuned real high...

 

[Phoenix Risen 10+ year member]

the box is actually 4.7 ft^3 gross

which with 3 4" aeros and sub displacement should put you close to 4 cubes net.

which puts you at 28" on each port, 32 puts you at 21 inches, that would still get you pretty low, and wont be a pain to do.

 

[CRXBMPN 5,000+ posts]

also he would need more couplers and tubes as the ports come 17" long (12" center pipe)

 

[miker 5,000+ posts]

also he would need more couplers and tubes as the ports come 17" long (12" center pipe)

Buy a piece of PVC? Would cost 10x less and you can easily cut them as long or short as you like.

On a side note.. How much of the flare do you measure for length?

 

[Phoenix Risen 10+ year member]

Buy a piece of PVC? Would cost 10x less and you can easily cut them as long or short as you like.
On a side note.. How much of the flare do you measure for length?

^^^ actually what im doing with my box, its just under 4 cubes with 3 4" aeros 20" long, in pvc

and the flares are .5" less usable than over all length

 

[Jason19 10+ year member]

Buy a piece of PVC? Would cost 10x less and you can easily cut them as long or short as you like.

would the flare ends fit on the pvc pretty eazy

 

[CRXBMPN 5,000+ posts]

i use bass box pro 6 which has a feature that allows you to add a port with two flared ends, so it will do my calcs for me.

and yes if you can find the same thickness pvc, its pretty thin, then pvc is a great alternative!

 

[Phoenix Risen 10+ year member]

ive seen the thin pvc at a couple places, i believe lowes had it at one point.

 

[Jason19 10+ year member]

3 x 4FLARE - PSP-4OFH

3 x 4FLARE - PSP-4IF

6 x 4FLARE - PSP-4RG

so that's what ill need I think and then ill just go pick up some pvc pipe if I can find some.

 

[Phoenix Risen 10+ year member]

what you need is 3 of each flare. and the rings that go with it, not sure what part numbers are what.

 

[Jason19 10+ year member]

do i need flares on both ends or no?

 

[Phoenix Risen 10+ year member]

yes the inner flare is just as important as the outer flare as it does most of the work cutting down turbulence

 

[CRXBMPN 5,000+ posts]

if you want to have flares on both ends then yes you need both... the outer flare is bigger than the inner one too, for mounting.