help tuning port(s) in a clamshell

[germandark 0]

I have a desired tuning frequency that I want but I will have two ports...I think.

The best example I could find is in the Stealth Avalanche build, basically the same idea he did but in a different vehicle and different subs, bit more air space.

Here is what it looks like.

As you can see, there is a port with a partition in between. So my question is, how do I figure out what to tune too. Do I tune each port to what I want the tuning to be...do I need to do some calculating and figure it out through equations....I could use some help on this subject.

Also how does this type of enclosure work since the port is firing directly in front of the subs? I would assume there is some kind of db level gain...

[germandark 0]

no one? guess it'll be trial and error then.

[bassahaulic 155]

no one? guess it'll be trial and error then.

That's the best way!! I'm doing that with my wall haha

[christobear 0]

the way it was explained to me is that for 2 ports, you tune each port to half the box. so if you have say a 10 cube box, you would tune each port to 5 cubes at whatever Hz

from JL

"Divide the chamber volume by the number of ports you wish to use for that one chamber.

• Take the quotient and use that as your Vb (box volume) in the port formula

• Do the number crunching and figure out how long each port should be."

Edited January 23, 2009 by christobear

[germandark 0]

the way it was explained to me is that for 2 ports, you tune each port to half the box. so if you have say a 10 cube box, you would tune each port to 5 cubes at whatever Hz

from JL

"Divide the chamber volume by the number of ports you wish to use for that one chamber.

[germandark 0]

Update.\/\/\/

okay here is my pos sketch up # 1

each port has (rounded up) 85in^ of port area.

each is tuned to 36 hz. <<<< am I supposed to tune each port to the total desire tuning or what??

each side is 8.125ft cubed.

______

My port area is a bit small, I know.

I would glass corners/etc. and use threaded rod for bracing. I was thinking of double baffle for the subs.

this is my first mock up...I am not too happy but I will keep on.

ALSO I plan on dc level 4 15's

[germandark 0]

ttt

[a1161979 3]

Looks very interesting, i know little about clamshells or the benefits they offer but they seem kinda like hybrid horns that you see in PA cabs

Im looking forward to seeing a build log, and that picture is sick

[germandark 0]

#2 here.

6.73ft cubed each side, 6.93 before guesstimated displacement.

99in^ of port area for each side, total of 198in^

effective port length is 24.5in so Ill just say 24in.

tuned to 35 hertz, actually 35 point something.

questions & comments?

[BigDaddy13440 3]

#2 here.

6.73ft cubed each side, 6.93 before guesstimated displacement.

99in^ of port area for each side, total of 198in^

effective port length is 24.5in so Ill just say 24in.

tuned to 35 hertz, actually 35 point something.

questions & comments?

those look pretty friggin' cool to me!

what are you planning on putting it in?

I'm thinking of something similar using (2) 10's in a center console, with the port firing across the subs, maybe acoustically coupling the output of the front and back wave???

[germandark 0]

here is mock up #3 it is very much like supergumby's. I followed his advice on taking the subs "out of the port." this gave me less air space but the subs will still be getting enough and each chamber is tuned to 32 hertz with 79in^ of port area. it is more a true clam shell now. I really like this design.

again it will all be braced with threaded rod and fiberglass.

questions & comments.

edit: after doing some other measurements, tuning maybe actually be around 30 hz. anyways its very low 30's

[germandark 0]

bump for constructive criticisim

[tezin87 0]

This is for a ranger, right? If so I'll be watching this very closely. I'm wanting to try a blowthrough this summer...good luck man.

[danieln_88 0]

it looks good....

better post a build log of this one!!!!

[germandark 0]

I believe #3 will be my enclosure. I'm going to call my conect. and purchase soon.

[galacticmonkey 0]

What about making it a clamshell with a port on each side?

[germandark 0]

Chuck, have a look-see at mock up three. I almost certain this is what I want to build.