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View Full Version : What to expect with larger ports?



heyman421
07-09-2006, 12:16 AM
Right now i have a box that measures 9.9 gross, so 9.057 cubes net internal for my 2 15" L7's (06) and the box only has a 9.5 x 4" port, so 38 square inches of port.....

How big of a difference would there be if i were to remove this smallish port, and replace it with 4 6" aeroports, or pvc ports?

Tunnig will remain the same, 33hz, i was just curious what effect on output more than doubling my port area would have, and whether or not it would be an actual noteable difference, and worth the time and effort?

Thanks guys.

heyman421
07-09-2006, 12:19 AM
and is there a program that will make it easier to figure out port lengths while keeping in mind port displacement???? My brain is tying itself in knots....

or do i just need to keep trial and erroring with precision's port calculator? cause i'm not even getting close

MadAudio
07-09-2006, 01:05 AM
and is there a program that will make it easier to figure out port lengths while keeping in mind port displacement???? My brain is tying itself in knots....

or do i just need to keep trial and erroring with precision's port calculator? cause i'm not even getting close
just use winisd and subtract your port displacement from the box size .
i also want to know what happens with a bigger port .
the new box is almost done its close to the size of my old box but it has a much larger port i went from a 4" round to a 5"x5" square port . but it will be a couple of days before i can listen to it box still needs lid attatched the edges round over and carpet .

dleccord
07-09-2006, 01:09 AM
doesnt it increase excursion? or is that when you jump to a bigger box?

heyman421
07-09-2006, 01:30 AM
well, i figured out if i have 8 4" ports, 24.5" long, i'll be right around 35hz.......

subs are inverted to save room, those ports add up when you jump from 38 square inches to 100........

and i'd use 4 6" ports instead, but i don't know how to cut a 6" hole perfect enough to seal up with silicone....... i figured with 4" ports, i can just use a 4" hole saw...

blue93corsica
07-09-2006, 08:55 AM
router and circle jig ftw

djman37
07-09-2006, 08:59 AM
4 6" would be too many IMO.
Try just 2 6" Aeroports. With 4 you'd start to eat up your whole box with ports/length. 2 ports=half as long too.

heyman421
07-09-2006, 08:29 PM
i got up this morning, and went to lowes and home depot, and holy crap, the amount of 6" pvc i would need is a lot more than i expected......

Plus, by modifying my existing box with aeroports, i'm going to have to either comprimise a whole lot of my internal net volume, or have big, ugly pvc ports sticking out of my box, and it's my daily driver.

I decided to wait a few days until i get my refund check for my returned type-r's from best buy, and build myself a new box....... I'd rather excercise some restraint, and wait for perfection.

Once my refund gets here, i'm gonna buy a router table for my milwaukee, a 1/2" tongue and groove bit set, and some 1/2" birch, and build myself a 9 cube box with a 3" x 40" port shooting out the back.......

If THAT doesn't get loud, i'll be filling the box with explosives, and climbing in.....

Let's hope it gets loud, i'm tired of these clown builders wasting my f'ing time and money, time for me to hone my building skills and get real.....

Number one thing i'm worried about is my absolute crap upholstering skills, so i'm just gonna stain the box, and go for a **** woodgrain finish.

Flipx99
07-09-2006, 08:31 PM
4 x 4in ports is what I would reccomend

heyman421
07-09-2006, 08:34 PM
Even with a 120 square port, it'll only have to be 16" long, so it wont even need to have a corner, so i wont be losing any performance compared to aeros......

plus, i wasn't going to buy real aeros either, i was just gonna use pvc, so i'm better off with a new box, i think

even with 4" aeros, my internal net volume would drop from 9.05 to under 8......

heyman421
07-09-2006, 09:29 PM
here's a mockup of the box.... it's really not terribly large........

dimensions are 41" x 27" x 16" with the port 3" x 40" x 16"

tuning will be ~33hz, subwoofers mounted upside down to keep height reasonable

http://img260.imageshack.us/img260/6776/box9uu.jpg

heyman421
07-09-2006, 09:30 PM
should be a fairly easy box to build, no tricks

i think it was harder for me to use that program, actually, i think tongue and groove joints will ease the build process, granted i can afford a table to do it on

heyman421
07-10-2006, 12:25 PM
4 6" would be too many IMO.
Try just 2 6" Aeroports. With 4 you'd start to eat up your whole box with ports/length. 2 ports=half as long too.

ya, i talked to someone at kicker today, and he told me that's too big

he said for a 4.5-5.0 cf box, 50 square inches per sub is ideal, so my port will be 2.5" x 40"