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View Full Version : 4" aero port cut length needed ASAP

da box king
07-03-2009, 12:13 AM
I cant figure out this **** sheet with the aero ports for tuning. I'm tryin to figure out how long to cut the pipe.

I have 4.75 cu ft, and I want a 30 hz tuning using 2- 4" aero's

Would you please be able to tell me how long the center tube needs to be?
Using their formula, it is sloppy as hell. Just was trying to figure out my "lv"

JUST HOW LONG DOES THE PIPE NEED TO BE EXCLUDING THE FLARES? Then I can just put them together

l7runner
07-03-2009, 12:17 AM
internal or external aeros?

MakeshiftAudio
07-03-2009, 12:18 AM
2(4*pi)=25.1327412in^2, which is the same as a single 5.66" pipe

Plug that in with a 5.66" dia pipe in a box that has 4.75 cubic feet of room(excluding port) tuned to 30Hz results in the pipe being 11.72096" long, so you need 2 11.72096" long pipes. This calculation goes smoothly for external ports.

Correct me if I'm wrong.

hockey512546
07-03-2009, 12:19 AM
13.33" with 2 free ends
12.86" with one flare
12.39" with two flares
WinISD

Just subtract the 1/2 flare length from that...

da box king
07-03-2009, 12:20 AM
internal ports

da box king
07-03-2009, 12:21 AM
both ends are flared btw

so how long is the pipe minus the flare?

thx guys

and how long for 32 hz......got 2 new XXX's off 4000 watts..Box is 4.75 net
I was thinkin 32 would be a lil better since the box is good sized

528hz
07-03-2009, 12:27 AM
Why don't you just use the calclulator:

http://www.psp-inc.com/

da box king
07-03-2009, 12:28 AM
and the box volume already has the ports volume takin out

and that calculator is confusing too

MakeshiftAudio
07-03-2009, 12:30 AM
Psh, precision ports. Use PVC. 6" is too small anyways. :crazy:

528hz
07-03-2009, 12:30 AM
:laugh: Confusing?

It does everything for you. You have all the information...

da box king
07-03-2009, 12:31 AM
is the volume using is the psp calc before or after port dis?

skmfkr
07-03-2009, 12:31 AM
wow the calc says 12" long so make them 12" long including the flared ends. i think they are like 17" 3/4" long the way the come so cut off 4 3/4" and you should be using 3 4" aeros with that size box, but u could only do 33hz with them at full legnth. and im pretty sure it does NET vol after all displacement. since what matters is how much room the sub can use anyways

da box king
07-03-2009, 12:32 AM
I got 11.86 " flared with 5.46 cu ft b4 dis of port

hockey512546
07-03-2009, 12:32 AM
Are you sure 2 4's will give you enough port area?
comes out to be 5.288 in^2 per cube

528hz
07-03-2009, 12:33 AM
is the volume using is the psp calc before or after port dis?

Good question...I don't know. I always assumed that it did NOT take that into consideration.

da box king
07-03-2009, 12:33 AM
wow the calc says 12" long so make them 12" long including the port. i think they are like 17" 3/4" long the way the come so cut off 4 3/4"

the flares add how much length?

skmfkr
07-03-2009, 12:36 AM
the flares are like an inch each or so. get a tape measure and measure them

da box king
07-03-2009, 12:36 AM
Are you sure 2 4's will give you enough port area?
comes out to be 5.288 in^2 per cube

I did not design the box....did the best with the dim given

and with aero's you would dbl the 5.288

da box king
07-03-2009, 01:14 AM
skmskr came thru...too bad his phone died...haha

thanks man

skmfkr
07-03-2009, 01:15 AM
you dont double it. i really wish someone didnt say aeros need half as much port area. square ports are 12-16 and aeros are like 8-10 which is roughly half. which is way i said 3 4" aeros would be better it would give you 37 square inches of port area for ur 4.7cubes which is 7.8 square inches per cube. but the ports would need to be like full length to have similar tuning

lol i told u it was gonna die

da box king
07-03-2009, 01:18 AM