PDA

View Full Version : Ports sound like a$$



mebcop
07-08-2009, 11:07 PM
Well, I put together a quick box today to house my type-r 10's....

It is 33x15Hx12D, and after displacements ports and subs taken out it's 2.4ft^3

I used the port length calculator and using dual 3" ports that are 10.5" long, it gives me a tuning of around 35Hz....

I put it all together today and I fired it up... Well, it hits REAL deep, but I have HORRIBLE port noise!!! I don't know if I need bigger/more ports, or if it's just my port placement.

I made up a quick "Paint" example of my box. It kinds sounds like the air coming out of the ports is fighting against itself, maybe cuz the ports are too close together???

Please help me....

http://i149.photobucket.com/albums/s48/mebcop/ISUCK.jpg

Just a quick explanation....

the subs are rear firing and the ports are top firing.... This is a view from directly over my box.....

l7runner
07-08-2009, 11:11 PM
need more port area. You should have approx 15 square inches of port per cubic foot of box volume.

loosely translates to one 4" port per cubic foot of box

DonH
07-08-2009, 11:14 PM
more port area u def. need!

mebcop
07-08-2009, 11:20 PM
I don't have the depth for a 4" port for each sub... This is turning into a huge pain in the buttocks....

I did the calculation real quick and I'd need two 4" ports almost 19" long EACH.....

bubbagumper6
07-08-2009, 11:24 PM
Did you post your plans on here before you built the box? If you would have checked on here first, someone could have told you this before you built the box....

l7runner
07-08-2009, 11:26 PM
external ports are always an option. Or cut it out and use square ports to size.

mebcop
07-08-2009, 11:26 PM
Thanx Bubba.... I needed some salt in that wound.... haha

mebcop
07-08-2009, 11:54 PM
OK, new plan.... 2" slot port. With the shallow depth I'm using, I can't go with any wider of a slot port, due to mounting depth restrictions.....

I punched in some #'s on the RE calculator, what do you think:

Red #s:

33
17
12.5
12.5
.75
2
5

It gives me 36Hz and 2.77ft^3

Is that port long enough or does it matter?

fshanda
07-09-2009, 08:20 AM
3" ports for 10" type R's just dont work even on smaller enclosures. I have no idea why Alpine specs such a small port size in their own manual. I had to chop my first box up and switch to a 4 to get rid of the noise.

fshanda
07-09-2009, 08:34 AM
And just quickly glancing at your dimensions you could use 4 " ports. Move your subs all the way to the sides and stack your ports side by side / left to right instead of front to back. Mount them in the front or back and use and elbow if you need more port length. That might net you 19-22" of port length and still be able to stay 4" off the back wall.

20 1/4" each at 4" is what I come up with using the existing displacement and even with taking it down to 2.2^3 I come up with about 22 1/4".

bubbagumper6
07-09-2009, 08:36 AM
OK, new plan.... 2" slot port. With the shallow depth I'm using, I can't go with any wider of a slot port, due to mounting depth restrictions.....

I punched in some #'s on the RE calculator, what do you think:

Red #s:

33
17
12.5
12.5
.75
2
5

It gives me 36Hz and 2.77ft^3

Is that port long enough or does it matter?

How tall is the slot port?

dappa5
07-09-2009, 09:38 AM
it th RE calc the port is full height of interior of box

bubbagumper6
07-09-2009, 09:46 AM
Ok well I don't feel like going to the RE site and recreating your box so how about you just post what the port dimensions are?

dappa5
07-09-2009, 10:03 AM
Re calc is off two or three hz
plus it only calc slot ports (a port using side wall of box as one wall of port )
you are not using a slot port if you want to put it where the aeros were
http://www.the12volt.com/caraudio/boxcalcs.asp
this will be slightly more helpfull