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View Full Version : port length and diameter is based on??



ace_800
11-12-2011, 06:23 PM
Having the guy build my enclosure and he wants to know the port length and port Diameter. I normally just use the calculator on 12volt, but it is based on the size of the enclosure correct? Each sub is going in a .6 ^3 enclosure, so i really can't do 20" straight length port so do i need to wrap the port like a tline to get the 20"?

pro-rabbit
11-12-2011, 06:32 PM
What subs and what are the specs of the enclosure going to be?

ace_800
11-12-2011, 07:18 PM
Subs are 2 SA8 's. Enclosure is a false floor so specs are weird. I've got about .7^3 of space per chamber mAybe a little less.

pro-rabbit
11-12-2011, 07:23 PM
Is that before or after displacements?

ahole-ic
11-12-2011, 07:24 PM
Subs are 2 SA8 's. Enclosure is a false floor so specs are weird. I've got about .7^3 of space per chamber mAybe a little less.

I would not port that. Run that sealed.

ace_800
11-12-2011, 07:25 PM
After

Jacob suggests .6 @35Hz. And i hear these don't sound good sealed.

pro-rabbit
11-12-2011, 07:27 PM
After

Jacob suggests .6 @35Hz.

So what is your gross space then? After wood but before port/sub.

Kangaroux
11-12-2011, 07:27 PM
Well, if you do a single 4" aero it will need to be roughly 20 inches long. Ideally you would probably want 2x 3" aeros

ace_800
11-12-2011, 07:42 PM
Its like .72 before roughly.

I can't use 3" aeros. Figure its ~8" high and ~14.5" length and width. Each sub in a separate port on the side with the amp in the middle. Dude is taking about using space under the amp for port length. I don't want to run sealed.

ahole-ic
11-12-2011, 07:44 PM
Its like .72 before roughly.

I can't use 3" aeros. Figure its ~8" high and ~14.5" length and width. Each sub in a separate port on the side with the amp in the middle. Dude is taking about using space under the amp for port length. I don't want to run sealed.
Then you'd better just go with 1 sub. You simply don't have the volume to go ported (with sufficient volume, port area, and tuning) and run 2 subs.

ace_800
11-12-2011, 08:01 PM
How thou when that's the suggested specs. .6 at 35 hTz and that's .72 for each sub.

Kangaroux
11-12-2011, 08:03 PM
Unless you go very low on port area so your port length is really short it's not going to sound good. If you are too little port area it's more like having a leaky sealed box than anything.

pro-rabbit
11-12-2011, 08:07 PM
What is suggested is to go with .7ft3 after all displacements not before. You would need 100% of the port outside the enclosure to keep the volume you have now.

ace_800
11-12-2011, 08:41 PM
From what Jacob has said its .6 after all displacement which i should be at and i can gain room by using space below the amp

pro-rabbit
11-12-2011, 08:43 PM
A port unless fully outside those specs will take up way to much room. If you can create an external port then yes it will work. Otherwise, no it will not.

Nut Hair Trick
11-12-2011, 08:50 PM
what are the measurements you have to work with?

ace_800
11-13-2011, 12:24 AM
Its a false floor so I don't know the exact specs. There is no chambers at the moment just external "shell" if you want to say. I'm at over 2^3 at the moment so the builder is trying to get the right port size down. Here is what the build is kind of right now.

The top view and the side view. I am either looking at making both like the right side of the lower drawing or both like the left side. Just need to see if there is an issue making the port like either. The guy building it is just wanting to know what the port length and diameter should be. The black space on the left would be empty space if the left port length would work. It would be on both sides.

http://i67.photobucket.com/albums/h301/xconcepts/Untitled.png

ace_800
11-13-2011, 12:44 PM
bump

ahole-ic
11-13-2011, 12:50 PM
Wow. You're going to hate that thing... no offense. different port lengths. It's a really bad design. Might look nice but won't perform worth a ****.

ace_800
11-13-2011, 01:27 PM
Come on Crack gotta read. Im either having the right side done or the left. Inside hasn't been done. They WILL NOT be different ports

duanebro
11-13-2011, 01:28 PM
I'd try running the port under the amp. coming out next to the other sub. One would be in front of the other. If you can get some measurements with the drawings I will see how big the ports can be.

Duane

ahole-ic
11-13-2011, 01:30 PM
Come on Crack gotta read. Im either having the right side done or the left. Inside hasn't been done. They WILL NOT be different ports

I read it. It didn't make sense to me so I commented. You are killing me though. You asked for help, and when people give it to you, you argue. It looks like you wanted a circle jerk of people telling you how awesome your idea was. Instead of doing that and setting you up for disappointment, we are trying to prevent you from making a mistake and wasting money. You should listen to us. We are on your side even though it might not sound that way to you right now.

ace_800
11-13-2011, 01:49 PM
Not arguing at all, kinda hard to do expression. guess i should have said lol. I don't understand why it will sound bad if i run the port under the amp thou.

duanebro
11-13-2011, 02:24 PM
I think it will be fine. You are using external ports; I don't think that was clear at the beginning. How much space do you have to work with under the amp?

ace_800
11-13-2011, 02:37 PM
Guess i don't understand external ports then. Thought that having the port under the amp was still an internal port and external port would be outside the box. say an aero port that is outside the enclosure. i didn't know you could do an external slot port.

There is near a cube under the amp.

Nut Hair Trick
11-13-2011, 02:37 PM
You will gain more space when going with one port instead of 2, and obviously this is a concern of yours. Also with this, port area can be bigger and more effective. Group the subs together in a common chamber on one side, port on the other side.

pro-rabbit
11-13-2011, 03:03 PM
You will gain more space when going with one port instead of 2, and obviously this is a concern of yours. Also with this, port area can be bigger and more effective. Group the subs together in a common chamber on one side, port on the other side.

This would be what I think as well. Hard to say how it will perform as you don't even know the dims of the enclosure. With out knowing that I'm not sure how you can create a port with the correct port area and length for tuning.

You can take a guess I supposed, but then your stuck if you don't like it. Are you using an enclosure builder or just a good carpenter? Any decent enclosure builder should be able to figure out the specs on the space you have to work with and figure out a decent option for the application.

ace_800
11-13-2011, 03:25 PM
Yeah im using Audio 2000 here in Tucson. He knows the specs/dimensions of it. I just don't and he was asking if i knew a way besides email to reach Jacob for port length and diameter. I only knew what he told me about .6 @35 htz. Ill go with both subs on one side and port on opposite if i have too. again its not cut for the subs yet