ported enclosure

[CrownVic 15]

Hello this is my first post here.

Ive been researching and looking at subs for a while trying to decide what sub to put in my 86 crown vic. Ive been pointed towards IA and have heard many good things about them thats why i am gonna go with the 187 15.

I was gonna put it in a ported box. I have plenty of space for a box in my trunk I have looked and researched sub calculators and all that but still don't know how to determine the frequency and portsize or design. Im going for a mix of volume and sound quality. And would like to know how to pick the frequency, how to tune the box to that, and what portsize. My dad is a carpenter and i was gonna give him the demensions and he will build it from 3/4 MDF.

Thanks for your help.

[KU40 173]

Try downloading winISD. It has a port calculator in it. This site also has one. Just remember that when you make the port, you have to add that and sub displacement to the gross box size. So if you want the sub to "see" 4 cubic feet but the port displaces 1 cube and the sub .15, you need to make a box that's 5.15 cubic feet internally. But when you use these port calculators, only use the 4 cubic feet as the box size parameter, as they only want net volume.

Tuning frequency is a combination of what the sub likes and personal preference. I personally like 30 hz, and for you something between 30 and 32 sounds like it would be good.

[CrownVic 15]

Try downloading winISD. It has a port calculator in it. This site also has one. Just remember that when you make the port, you have to add that and sub displacement to the gross box size. So if you want the sub to "see" 4 cubic feet but the port displaces 1 cube and the sub .15, you need to make a box that's 5.15 cubic feet internally. But when you use these port calculators, only use the 4 cubic feet as the box size parameter, as they only want net volume.

Tuning frequency is a combination of what the sub likes and personal preference. I personally like 30 hz, and for you something between 30 and 32 sounds like it would be good.

ok thanks man do you know of a good place to download if from.

[KU40 173]

I think www.linearteam.org is the only place.

[CrownVic 15]

I was looking at winsid on the web page here http://www.linearteam.dk/default.aspx?pageid=newdriver and i was wondering what to put in the last four boxes to the right. Im sorry for the noobness but im trying to learn.

Also its going in the trunk so theres plenty of space for the box, and i plan on using a memphis class D 1000w amp 500watts rms at 4 ohms. I havent bought it yet so if it wont work or isnt right i can get somthing different.

Edited August 15, 2009 by CrownVic

[KU40 173]

Those boxes on the right are only for a 6th order bandpass. Since you want a ported box, you'll only use the two boxes under "vented." I've never used that portion of the site, though. I just downloaded the actual program. I have winISD Pro.

[CrownVic 15]

ok thanks

[CrownVic 15]

ok so i entered the data. But dont know what unit the volume is. The website just has X?

with a box frequency of 19.35?

any help here?

[KU40 173]

Did you download the actual program?

[CrownVic 15]

no. Ill download the program and try it. then get back with you.

[CrownVic 15]

So i ran the program and entered the specs for the driver i was using then used that driver for a vented box and got the same thing.

It Had the Volume for 710L and the frequency for 19.35 then below it it said Ql 7.0. Is the Ql ohm load?

I just need to know how big to build the box and how big of port it needs can someone please help me with that?

Also its a rectangle box with a slot port.

Edited August 16, 2009 by CrownVic

[KU40 173]

For box size and tuning recommendations, always go to the manufacturer first. Although now as I go to their site I see they don't have a recommendation for the 15. I've never used the sub, but I would imagine 4 cubes tuned to 32 hz would be fine. A slot port with about 35-40 sq. inches would be sufficient. You can plug those numbers into winISD and it'll tell you how long to make the port.

[CrownVic 15]

How do i tune the box?

and 40in sq couldnt that just 10" tall and 4" wide? for the port

[KU40 173]

The box is tuned according to the net volume of the box, port area, and port length. so by adjusting any of those parameters, you adjust the tuning frequency of the box.

Yes, a 10" x 4" port would be 40 sq. inches. But since you're using 15" subs I imagine you'll be making the box at least 16" tall? You could make the port the whole height of the box so that it's easier to construct the port. So with a 16" tall outer height box, the inner height using 3/4" wood would be 14.5". So you could make a 14.5" x 2.5" wide port and have 36.25 sq. inches of port. But that's just an example. However, you don't want to go over about a 1:9 width to height ratio for the port. So don't make like a 20" x 2" port.

[CrownVic 15]

Ok thanks man. I guess ill just make the volume around 4cubes. with 40-55 inches