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View Full Version : How exactly does an adjustable port work?



Germ305
10-04-2011, 03:57 PM
In the sense of how do you adjust it?....I've seen builds of enclosures with an adjustable port but could never quite grasp how you adjust it the only adjustable ones i do get are the aeroport ones lol Does anyone have pics or can explain to me exactly how it works?....Also how difficult are these to build vs a normal ported enclosure?

kushy_dreams
10-04-2011, 09:50 PM
Well for mine I have 2 different length port tubes with my aeroports so all I do is unwrap the electrical tape that holds the sections together and retape in the desired section.

i2ain2thunder
10-04-2011, 09:51 PM
deathbox isn't exactly a changable port to say.. ....but
well it's kinda like a tune-able port

brodeisel
10-04-2011, 09:55 PM
well explain the changeable port

i2ain2thunder
10-04-2011, 10:00 PM
I'm just thinking about how I'd attempt it, would be with like a slot port and just have some other panel of mdf cut to fit inside and take up exactly enough width to change the port tuning to the other desired frequency and you could even have different sizes for differing tuning. Then simply screw them into one another, not the best solution as it might not be air tight but it would work just fine.

i2ain2thunder
10-05-2011, 12:19 AM
The deathbox has an adjustable baffle that changes the way the horn reacts to different frequency ranges, so you can basically move the baffle around inside the box and inside your own trunk/back. A useful feature if you do not already know how to tune a ported enclosure to your vehicle's trunk/back.

Germ305
10-05-2011, 12:37 AM
Ok i looked up a "Deathbox" and that is not exactly to what i was referring to...gimme a sec...someone here is selling a sub and box with an adjustable port.

Germ305
10-05-2011, 12:42 AM
http://www.caraudio.com/forums/attachments/subwoofer-classifieds/26524321d1303800085-re-xxx-18-d1-img_1035.jpg
Owner of this pic is "Beach22" here on the forums i hope he does not mind as this is to gain knowledge...but i believe he stated its tuned to 34hz and can be adjusted to 48?

Germ305
10-05-2011, 12:42 AM
Double.

morespl
10-05-2011, 01:19 AM
You can make a box then you make the port and make a outer ring that covers the gap with different length or actual port are. So basically you cut a gaping whole in the box and slide the port in. By making the port you have a piece of wood that covers the left overs of the port that way you can take it out fast and efficiently. With this method you can also make the port a external port.

Bettr n' Revrse
10-05-2011, 01:21 AM
When you move it (adjust it) it sounds different...... :D

Germ305
10-05-2011, 01:32 AM
When you move it (adjust it) it sounds different...... :D

It was soooooo simple! lmao...Na but i feel so dumb when it comes to enclosures like i need drawings or pics :\

Bettr n' Revrse
10-05-2011, 01:53 AM
I need to learn more about tuning and building cuz with my Cad experience I think it would be simple for me to design...

sacsking916
10-05-2011, 02:06 AM
I believe in subzeros build log he has pics of his interchangeable port

Germ305
10-05-2011, 02:22 AM
I PM'd him...hopefully he will come drop some insight

Germ305
10-05-2011, 02:23 AM
I need to learn more about tuning and building cuz with my Cad experience I think it would be simple for me to design...


I'm the guy who just builds it based on measurements and drawing designers put out. Math makes my head explode :\

subzero
10-05-2011, 03:09 AM
OK, check it out.

I went back to my old box because the new one was too big. In my car, for my application, the smaller box worked best.

So, my smaller box is a slot port tunned to 43hz, . My subs have a 1cube displacment combined so and the port also increases the displacment. so lets say 1.5 cubes displacment, leaves me with a 3 cube box, and the 43hz tunning. Now, sometimes I like to hear and feel the low lows, The fix is simple for me, My port is 5.5inches wide, 14.25 long. So I add 1 1/2 inch baffle to eat up port space, and thus making the tunning lower around 36hz. and it also on a personal note, the port pressure on the low tune is actually helping my subs handle more power and getting louder on the low side. THese subs are natural low end monsters since they have a 40mm xmax and a 4 inch coil capable of 5kw + and they have extreamely stiff susspension.


For other subs and boxes, it might not be the same.

i2ain2thunder
10-05-2011, 12:17 PM
OK, check it out.

I went back to my old box because the new one was too big. In my car, for my application, the smaller box worked best.

So, my smaller box is a slot port tunned to 43hz, . My subs have a 1cube displacment combined so and the port also increases the displacment. so lets say 1.5 cubes displacment, leaves me with a 3 cube box, and the 43hz tunning. Now, sometimes I like to hear and feel the low lows, The fix is simple for me, My port is 5.5inches wide, 14.25 long. So I add 1 1/2 inch baffle to eat up port space, and thus making the tunning lower around 36hz. and it also on a personal note, the port pressure on the low tune is actually helping my subs handle more power and getting louder on the low side. THese subs are natural low end monsters since they have a 40mm xmax and a 4 inch coil capable of 5kw + and they have extreamely stiff susspension.


For other subs and boxes, it might not be the same.

Ok so you basically did what I was saying earlier about just haveing differing width pieces of wood to insert into the slot port....I was thinking that would be the easiest route...not sure if the best route, but it would be very easy.

subzero
10-05-2011, 08:23 PM
Ok so you basically did what I was saying earlier about just haveing differing width pieces of wood to insert into the slot port....I was thinking that would be the easiest route...not sure if the best route, but it would be very easy.

sorry bro tl/dr before I posted. my response, but yea, I do that alot. it works for me. just tune high and add wood to eat up port space and lower tuning

nineball
10-13-2011, 08:58 PM
this is the box i built for testing 8s. i just used 3" pvc, a pair of couplers and various lengths of pvc between them to adjust the tuning. it won't win any aesthetic competitions but it makes adjusting the port very easy.

http://i15.photobucket.com/albums/a357/nineballots/IMG_0414.jpg
http://i15.photobucket.com/albums/a357/nineballots/IMG_0418.jpg

RAM_Designs
10-14-2011, 01:50 PM
^^^good for testing.