# Stuffing a port on a ported subwoofer box makes it sealed???



## Ultimateherts

Back when I just started getting into car audio years ago a friend told that he had stuffed the port on his subwoofer box with socks to make it a sealed enclosure!!! 

Other than altering the enclosure size, can you stuff a port or do you have to physically remove it in order to make the box sealed?


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## underdog

Layered Front Baffle
In addition to strength benefits if u counter sink ur sub , the double (maybe for you triple) baffle makes your box look better\neater too.
Use lots of adhesive


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## BuickGN

As far as I know, once you block the port off, it no longer functions as a port. It would be like throwing a piece of PVC inside of a sealed box, no effect other than a tiny amount of volume taken up. I would probably use something a little more solid than socks if you want to seal up a ported box like MDF.


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## trojan fan

I'm sure a sock only would have substantial air leaks


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## trojan fan

underdog said:


> Layered Front Baffle
> In addition to strength benefits if u counter sink ur sub , the double (maybe for you triple) baffle makes your box look better\neater too.
> Use lots of adhesive


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## BEAVER

I believe he suggesting to add a layer of MDF to the front of the enclosure. Seals the hole and creates a stiffer baffle, as well. 


Sent from my iPhone using Tapatalk


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## lbp775

I'm actually using a Hsu subwoofer in my theater that allows you to tune it by plugging up the ports with a pair of really dense foam pieces. 

Check out the pics.
VTF-2 MK4 Subwoofer


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## Victor_inox

lbp775 said:


> I'm actually using a Hsu subwoofer in my theater that allows you to tune it by plugging up the ports with a pair of really dense foam pieces.
> 
> Check out the pics.
> VTF-2 MK4 Subwoofer


B&W and KEF doing that all the time.


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## prion

If you have a round port, use a Test Ball pneumatic plumbing plug. Works great for testing purposes, could also be a long term solution.


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## for2nato

A sealed enclosure does not a sock make!

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## sqshoestring

It mostly works. If you stuff something in a port somewhat hard it will not flow enough air to matter to the sub, it will act very close to sealed. Though the ported box should be larger than ideal sealed, that would tune it a little lower. I know everyone on here says seal the crap out of everything but in reality the problem is noises from not sealing, the problem is not changing the response of the speaker until the leak gets large enough to flow a percentage of air. I don't know that percentage, but I know leaky boxes and IB don't care much about it far as the speaker response....leaks within reason of course. I've made mock ply boxes screwed with no sealant and fast hand skilsaw cuts that were not perfect, they worked fine. Likely made some noises from the leaks but I certainly could not hear them in the car with box in trunk. Made a permanent box and it sounded exactly the same. Speaker cone moves pretty fast, so the leak has to flow that fast too and a little tiny crack is not going to do that. Also your relationship of depth is like a port, meaning if the leak is deep it will tune like a port and not be out of phase and cancel everywhere. Such as a drill hole in 3/4 material, it would have to be a larger drill to tune high and cancel or unload (if it could flow enough to unload the driver).


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## Spyke

^ What he said...I think. Yes as long as it is mostly sealed it will function as a sealed box. If you push the cone in(evenly and firmly/and don't smash the dustcap) it should come back out slowly. If you push the cone in and it comes back too fast then it's not sealed well enough. I saw a box once that had removable plugs for the ports and I laughed. Reason being is that like Sq said a ported box is likely larger than it's sealed counterpart for the same sub. IMO, if it sounds good to you there's nothing wrong with it. However you could pick up a dual sub box for about 50 bucks so why bother with it.

EMPTY SPEAKER BOXES from Parts Express ship same day and come with 45 day money back guarantee. Free Shipping Available. Order free 10,000 product catalog.


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## sqshoestring

Thats the thing, if you have tons of test equipment and are tuning for an exact response, or you don't want any funny whistling/vibration noises in your SQ system then this is important to you. Some quality workmanship should avoid the issues anyway. I suppose plugging a port is more tuning options than none, but I just build the box to tune the way I want in the first place. It could be helpful with bought boxes even if the tuning is not entirely proper, I mean what else do you do with them. It would be cool to have an adjustable port and you could make the box smaller by inserting things inside. Unless its terrible you can do it all with electronics anyway.

If you take your ported box and stuff something in the port you will find it does not take much to make it inoperative, unless you lay some big power on it. Of course you lose the big spl bump from the port. Some guys have made boxes they change the ports for SPL and back to daily driver, but it may take some searching to find the threads. IIRC they don't go sealed both setups were ported on ones I saw.


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## jonbuilds

Ultimateherts said:


> Back when I just started getting into car audio years ago a friend told that he had stuffed the port on his subwoofer box with socks to make it a sealed enclosure!!!
> 
> Other than altering the enclosure size, can you stuff a port or do you have to physically remove it in order to make the box sealed?


Can of worms potential here very high...but if you want a sealed enclosure, then make a sealed enclosure by assuring that any openings are at LEAST as air tight as the least air-tight part of the rest of the enclosure, using a material at least as rigid as the rest of the box. (so I guess if your box is made of sox...) Sealed enclosures change the response characteristics of the enclosure and its interaction with the driver as compared to ported enclosures. I personally prefer a heavy, sealed enclosure designed with the speaker mfg's specs in mind, but that's just me. No reason to add ANOTHER variable (socks, tissue, rubber baby bumpers) if you can help it, since the size, placement, material, input power, and driver performance already give you plenty enough to think about and improve upon.

All that said, can't hurt to play with it. You might stumble on your vehicle's happy harmonic.

Best of luck
Jonathan


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## ChaunB3400

Just never understood why anyone would want to do this, if you want a sealed box build a sealed box, if you want a ported box build a ported box


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## Spyke

:laugh: I agree. I enjoy building enclosures and my audio storage room is proof. However, not everyone has the means to do so, imho.


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## Catman

lbp775 said:


> I'm actually using a Hsu subwoofer in my theater that allows you to tune it by plugging up the ports with a pair of really dense foam pieces.
> 
> Check out the pics.
> VTF-2 MK4 Subwoofer





Victor_inox said:


> B&W and KEF doing that all the time.





for2nato said:


> A sealed enclosure does not a sock make!


I agree with the above. What you are doing is making an 
aperiodic membrane.

Loudspeaker enclosure - Wikipedia, the free encyclopedia

It depends on how tightly you pack the sock. I have socks in a pair of speakers I'm using in a guest bedroom. They sound better. I thought the speakers needed a little more damping.



Also ...what others have said is true. In general a speaker requires a specific enclosure to meet specific applications. If you need a sealed ...build a sealed. You are getting into a bit of 'Voodoo science' with aperiodic membranes unless you have the ability and equipment to test what you are doing.


>^..^<


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## KSUWildcatFan

EEEEEEEP. Why do this?! Whyyyy?! I guess if the size is right then whatever. Can't imagine how it'd be close though..


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## sqshoestring

Socks are pretty dense, you pack them in and it is not AP its just an oversized sealed. Air has to flow through the membrane to be AP and it does not take much to stop that, excepting maybe some hard low bass notes, and that does not really count.

I can see how plugging ports could tell you different tuning is better/worse. IMO it does not matter how big a sealed is anyway, just different tuning and can be different power handling. I always made them larger than they said when I used them, though I tend to not use sealed much. But I will admit I would duct tape a port shut if it sounded better and all I had was tape and that box.....the sound is what counts.


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## scott0482

lbp775 said:


> I'm actually using a Hsu subwoofer in my theater that allows you to tune it by plugging up the ports with a pair of really dense foam pieces.
> 
> Check out the pics.
> VTF-2 MK4 Subwoofer


I wanted to do this years ago.
In a simplistic world. Plugging both ports would be sealed. But it would be a rather large sealed box. Plugging one port would be tuned lower, but removing both plugs would tune it higher.
It started to get complicated though. To really get what I wanted, I would have had to have the 2 ports be different diameters and 2 different lengths, but both have the same volume as each other so it could be run with both ports open. It would have given me 3 different tuning points, as well as sealed, but any calculation mistakes would have probably made it sound like crap.


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## lbp775

scott0482 said:


> I wanted to do this years ago.
> In a simplistic world. Plugging both ports would be sealed. But it would be a rather large sealed box. Plugging one port would be tuned lower, but removing both plugs would tune it higher.
> It started to get complicated though. To really get what I wanted, I would have had to have the 2 ports be different diameters and 2 different lengths, but both have the same volume as each other so it could be run with both ports open. It would have given me 3 different tuning points, as well as sealed, but any calculation mistakes would have probably made it sound like crap.


I hear you! Luckily Hsu has done the research and development for me. All I had to do is insert or remove the foam pieces to my liking. :rockon:


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## D-Bass

before i built my kickpanels, I once had a discussion with larry fredericks about taking my currently sealed kickpanels and porting them up into the dash with long flexible ports that would be stuffed with polyfill. seemed like it would model ok. i may still try it some day, but for now they sound great as is.


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## scientus

Resurrectin this post, I got an old q-logic 12 in single ported box with the port cylinder missing from a friend. I'm going to try and use it since it's only 1.07 in^3 but wanted to doublecheck. I've seen duct tape, mdf, and the proverbial sock suggested for plugging the box. Anyone want a final say?


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## minbari

I would not use socks or duct tape. but if you solidly seal up the hole, its now a sealed box. no magic here.


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## scientus

Thanks minbari


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## JohnVella

prion said:


> If you have a round port, use a Test Ball pneumatic plumbing plug. Works great for testing purposes, could also be a long term solution.


Thanks, its helpful for me


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## Victor_inox

Great idea!

Sent from my SAMSUNG-SGH-I527 using Tapatalk 2


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## Gary S

A ported box with a sock in it will sound like a sealed box with a hole in it stuffed with a sock


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## kustomkaraudio

Back in the day Oz audio had a interesting design. They called it " 100% stuffed ported box " 
They gave you the volume, port length and diameter of port. They recommended stretching grill cloth around the port on the inside of the box, and then stuffing the crap out of the box. They wanted you to have to push the woofer into the box. 

I remember building a few of these boxes and being impressed with the output and sound quality of these boxes. 

Seemed like a cool design, I don't know the science behind it, but I wonder why I haven't seen it done or replicated by other woofer companies in give or take 20 years ?


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## cajunner

kustomkaraudio said:


> Back in the day Oz audio had a interesting design. They called it " 100% stuffed ported box "
> They gave you the volume, port length and diameter of port. They recommended stretching grill cloth around the port on the inside of the box, and then stuffing the crap out of the box. They wanted you to have to push the woofer into the box.
> 
> I remember building a few of these boxes and being impressed with the output and sound quality of these boxes.
> 
> Seemed like a cool design, I don't know the science behind it, but I wonder why I haven't seen it done or replicated by other woofer companies in give or take 20 years ?


it's a compromised vent, not suitable for maximized acoustic principles but possibly making a pre-fab sound a little better from increased damping with a mild resonant bump at tuning.

a pure vented box with an unobstructed vent with flaring, will produce a stronger resonant peak, or counter-force to the cone's "spring" and allow a stronger response when combined with the speaker output.

I would suspect these compromised vents act like a passive radiator that is too light to control the cone well, but still allows for some control on the cone.

If you think about it, the column of air that is supposed to travel freely through the port, is being absorbed in the box and the amount of force on the sub's cone is less.


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