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valin
06-27-2009, 02:05 PM
I am about to build an enclosure for my two DD9515F's. I will be running 2Kw per driver. I was thinking of this:

8.5 cubes after displacement
slot port @ roughly 136 sq. inches. (16"x8.5"), with 38-40hz tuning
subs forward, port forward

This is going in an extended cab pickup.

Now, I will be putting the port in the middle of the enclosure. The enclosure is only going to be 23" deep. The port will be in the middle of the enclosure, and will have to be in a T shape. So, the port will be 16" tall x 8.5" wide. According to the RE calculator, the port length is only 8" for 34hz tuning. That does not seem right to me.

How long does the port have to be for 38 or 40 hz tuning? If the port is long enough to have to T it, do you run the entire width of the port (8.5") towards each side at the rear of the enclosure, or do you run 1/2 the width?

valin
06-27-2009, 10:35 PM
I also have four new 6" Aero's that I could use, but was thinking of doing a slot.

mlstrass
06-28-2009, 11:46 AM
port would be 18" long for 38Hz and 16" long for 40Hz. You want to stay 1/2 the port width off the rear wall, so 4.25"

If you end up needing a 1" or smaller "L" on the end of each port wall then I'd forget it and leave the tuning a fuzz higher...

audioqueboy
06-28-2009, 12:37 PM
port would be 18" long for 38Hz and 16" long for 40Hz. You want to stay 1/2 the port width off the rear wall, so 4.25"

If you end up needing a 1" or smaller "L" on the end of each port wall then I'd forget it and leave the tuning a fuzz higher...


He designed my box for me and it came out awesome. Sounds good on rap/jazz and old school.

8.5cuft tune 38 for daily :D

valin
06-28-2009, 01:49 PM
Since the box is 23" deep, I should be able to get away with a 16" port, which will leave me with 6.25" to the rear wall.

Thanks.

valin
06-28-2009, 01:52 PM
He designed my box for me and it came out awesome. Sounds good on rap/jazz and old school.

8.5cuft tune 38 for daily :D

What kind of deebeeez you pushing with that setup???

mlstrass
06-28-2009, 02:05 PM
hasn't had a chance to meter it yet. Gotta be right around a 150, pushes a lot of air...

valin
07-02-2009, 02:01 PM
Guys, can you check my math. RE's calculator is getting me all ****ed up.

Box is going to be 58" wide, 23" deep, 17.5" tall. That gives me 10.85 cubes gross with a double front baffle. I want to tune this enclosure in the 38-40hz range.

136 sq. inches of port - Should I go more?
DD 9515's = 0.48 cubes displacement ( I think)

Using this calculator at 38hz, it is giving me a port length of 15" http://www.carstereo.com/help/Articles.cfm?id=31

Using the RE calculator, putting in 8.5" for port width, and 0 for second port length, it is giving me a total port length of 27.25" and tuned at 33hz for some reason, and I have to put in a negative amount (-11.75) of length for the second length to get the enclosure into the 38hz range.

Here's the RE Calculator:

valin
07-02-2009, 02:02 PM
What length am I going to need to tune to 38hz, and what is the net internal volume going to be with the two DD 9515's?

l7runner
07-02-2009, 02:05 PM
RE's calculator tends to give people problems...I prefer to use this one

http://www.the12volt.com/caraudio/boxcalcs.asp

mlstrass
07-02-2009, 02:13 PM
18" = 38Hz tune assuming 16^2 of port area per net cube.

valin
07-02-2009, 02:21 PM
Would I benefit from throwing more port area at it?

mmouse57
07-02-2009, 03:33 PM
na more port area means longer port if you have space for it then sure alitt,le more port cant hurt but if not just leave it as planned should not get port noise with that size slot port just round the corners :)

valin
07-02-2009, 05:04 PM
Okie. Thanks again.