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Subwoofer Enclosures

sound ordnance sub boxes

The type of bass you get from your component subwoofer doesn't depend on the woofer alone. You'll need a strong, tightly-constructed enclosure for optimum subwoofer performance. Speakers without an enclosure can't deliver full bass because the sound from the back of the speaker can cancel out some low frequencies emanating from the front of the speaker.

Using our box-building accessories, you might choose to construct your own box to create the enclosure size that you want. However, unless you're a talented craftsman with a solid understanding of enclosure volumes and other technical terms, you're better off purchasing a pre-made enclosure, like one of the Sound Ordnance models shown above.

Box types

Different types of boxes will produce different types of bass:

Sealed boxes: For deep, precise bass

A sealed box is an airtight enclosure housing your subwoofer. A sealed box is best for any music that demands tight, accurate bass. Expect flat response (not excessively boomy), deep bass extension, and excellent power handling. Since a sealed enclosure tends to require more power than a ported box, use an amplifier with ample wattage for optimum performance.

Ported boxes: For forceful bass

Ported boxes use a vent (called a port) to reinforce low bass response. You get more output than you would from a sealed box at any given amplifier wattage. Some people prefer the sound of ported boxes for rock, heavy metal, or any hard-driving music. Ported boxes can deliver deeper bass than sealed boxes, though they need to be much larger than sealed enclosures to accomplish that.

Bandpass boxes: Maximum slam

Bandpass boxes are a special type of ported box designed for maximum slam. The woofer is mounted inside a dual-chambered box (one chamber sealed, the other ported), with the sound waves emerging from the ported side. The sound that comes out of the port is extra loud within a narrow frequency range.

Because bandpass boxes are super efficient within that range, they tend to boom. Their aggressive sound is great for rap, reggae, and hard rock. Not all subwoofers work well in bandpass boxes, though; consult our product information or call one of our Advisors to be sure.

Free-air subwoofers

A free-air system consists of woofers mounted to a board attached to the rear deck or placed in the trunk against the rear seat. The trunk of the car acts as an enclosure which houses the subwoofer and isolates sound from the back of the speaker, solving the sound cancellation problem of subs without an enclosure.

Free-air systems save space and have flat frequency response. The woofer must be specifically designed for free-air use. The lack of a box makes them more convenient to install, but their power handling levels are usually much lower than their boxed counterparts.

  • Marc Gagne from Deep River

    Posted on 5/9/2021

    What s causes a infinity box car subwoofer to make annoying bang sound ?

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    Alexander H. from Crutchfield

    on 5/14/2021

    Marc, if you bought the sub from us, give our Tech Support team a call for free help troubleshooting the sound. We'd need more information about the sound, when it occurs, etc.
  • Daniel rivera from bronx

    Posted on 4/18/2021

    I'm looking for a sub box for my evl 8inch d2 would you guys have one?

  • ROHAN MUDHALE from Kolhapur

    Posted on 10/18/2020

    Thank you Cruychfield... Information in simple manner... Whenever I need audio info there always crutchfield...

  • Michael Tice from Elmore, AL

    Posted on 4/27/2020

    I'm looking at some free air subwoofers for my boat but I don't want to cut any holes in it so I'm thinking about putting them in a ported box. Will they sound good that way and or would that be an okay thing to do.

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    Alexander H. from Crutchfield

    on 4/28/2020

    Michael, I've passed your question along to our Advisors for the best answer. Someone will contact you soon to help you find the right solution for your boat.
  • Zach Wilson from Saxonburg

    Posted on 10/1/2019

    Sundown 12 inch dual 2 ohm gunna run it in 1 ohm with my 1600 watt max amp 800rms . What would be a perfect box for it? Ported or sealed, size, material ? Cuz right now I only have a ported kicker comp r box and I'm assuming it wouldn't be good for the sundown . Sundown is on way in mail ??

  • Clevon Jones from Salisbury

    Posted on 8/17/2019

    what happens if your pre-fab box is tuned for 40 hrz and subs are designed for lower ?

  • Hoppy from BRISTOL

    Posted on 4/29/2019

    Can I put my RF p1 10 in a bandpass box?

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    Alexander H. from Crutchfield

    on 4/30/2019

    Hoppy, for all the details on recommended enclosures for this sub, check out the owner's manual available under "What's In The Box" on this page.
  • Jesse from Lompoc ca

    Posted on 3/24/2019

    I have a question I bought a set of 10 inch kenwoods in a bandpass box. Did some research and the box and subs where bought together as a package. So I shouldn't need a new box for more boom? I would assume the box is to specs for the subs already. they are kenwood BP-210

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    Alexander H. from Crutchfield

    on 3/26/2019

    Jesse, if you're unsure and would like to double-check, you could call Kenwood at 1-800-536-9663.
  • David W Freye from Norfolk

    Posted on 11/8/2018

    I have a weird question. The next phase of my car audio install is to build a custom subwoofer box for my two 12" subs and a rack for my amps. I just had a crazy idea but not sure of the practicality or sound. I was thinking I might remove the 40 side of my split 60/40 back seat. Would it produce any sound difference if the box was made for one 12 firing front into the cab from the removed 40 side and the other 12" firing back into the trunk? I also didnt know if in this kind of setup if mixing one ported vs non ported would help with a mix of Boom and sound quality?

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    Alexander H. from Crutchfield

    on 11/20/2018

    David, this sounds like a very cool project. You may find this article helpful on the topic of sub placement. I've also passed your questions along to an advisor for help. Someone will contact you soon with recommendations.
  • Shawn from Edgerton, Ks

    Posted on 9/28/2018

    Im am looking for a single 18in sealed sub box. Do you know were i can get one at

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    Alexander Hrabe from Crutchfield

    on 10/1/2018

    Sorry, Shawn. If it's for a car, the largest box we carry is for a 15" sub.
  • Rafael Rodriguez from St. Louis

    Posted on 6/6/2018

    I have 2 10" Boston G2 in a band pass box. Is that the ideal box for those subs? I'm running a Kenwood 1800 watt amp with them.

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    Alexander Hrabe from Crutchfield

    on 6/7/2018

    Rafael, here's the information on the G210-4 supplied by Boston Acoustics: Sealed Enclosure: The G2104 woofer is optimized for use in a small sealed enclosure with a 0.5 cu. ft. internal volume. Ported Enclosure: The woofer can also be used in a 1.3 cu. ft. ported enclosure with a 3" diameter, 10" long port, and tuned to 37Hz. For recommendations on a band pass box, your best bet is to contact Boston Acoustics tech support at 1-877-924-5817.
  • Anthony from Los Angeles

    Posted on 5/25/2018

    I have dual Polk 12" MM1240 SVC subs. The sealed internal dimensions call for a .88 Cubic foot space. Does it matter if the box is slightly larger? Say, one cubic foot. Does it change the sound?

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    Alexander Hrabe from Crutchfield

    Posted on 10/12/2017

    Meade, in the end, ported or sealed might come down to preference. Check out this article for an overview of the differences.

  • Meade Morgan from Easton

    Posted on 10/10/2017

    I have 2 vintage 6x9 Kicker Freeair subwoofers. I want to put them in my 96 VW MKIII Cabrio,using 6x9 speaker boxes on the back seat.Do I need to port the boxes or will they be ok sealed? I will be using an old Kicker Impulse Amp 125 watts by 2. I may use it bridged at 4 ohms,the subs are 8 ohms. Thanks for your help.

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    Robert Ferency-Viars from Crutchfield

    Posted on 9/21/2017

    Aaron, what you're describing is called a band-pass box. They play loud and push the subs hard. Make sure that your subs are recommended for band-pass use (check the owner's manual or the Planet Audio's website). That Boss amp should deliver enough power for the two subs.

  • Aaron V from Sacramento. can.

    Posted on 9/19/2017

    Yes wil a ported box ( it's an unusually box both speakers are angled about a 45° angle facing each other with a plastic see threw peace in front of both speakers and each speaker has 2 port holes on each side of each speaker) be alright for two 10" planet audio subwoofers rated at 1500 watts, am pushing them with a boss monoblock Armor 1500 watt amp.

  • Mark Lichte from Tampa

    Posted on 7/14/2017

    I'm looking for a sealed box type but I need to protect the speaker as much as possible. A bandpass wld do the trick but don't need all the boom. What if a single 8" w/dual voice coil in a bandpass. Space is a preium also

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    Alexander Hrabe from Crutchfield

    Posted on 5/24/2017

    Onur, JL Audio only makes these recommendations:Enclosure Compatibility Sealed Enclosure: JL Audio recommends an optimum sealed enclosure volume for the 8W1v3-4 of 0.35 ft³, resulting in a -3dB point of 59.9 Hz. Ported Enclosure: JL Audio recommends an optimum ported enclosure volume for the 8W1v3-4 of 0.5 ft³. The recommended port is 2" (diameter) x 10" (long), resulting in a tuning frequency of 38 Hz and a -3dB point of 39.1 Hz. They don't recommend a bandpass enclosure for optimal performance. If you still want to build one, you might try a related forum for recommendations from other users.

  • Onur from Istanbul

    Posted on 5/23/2017

    Hi, can ı help you? I use jl audio 8w1v3 subwoofer. I need a make bandpass box. I have subwoofer all parameters. I consulted JL. They did not recommend. But I want to try it. How should the volume of two compartments be? How many ports should I use?

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    Robert Ferency-Viars from Crutchfield

    Posted on 3/30/2017

    Adrian, what matters most is appropriate box volume. If the box is too big, the sub isn't going to sound good. If 3.0 cu. Ft. is within the manufacturer's recommended specs for a ported box, then yes, go for it. Otherwise, build the largest box you can, based on manufacturer recommendations and cheat the port placement a little.

  • Adrian Underwood from Port Orchard, Wa

    Posted on 3/25/2017

    I have an infinity kappa 120.9w. I just bought a precision port 4 inch aero port kit from parts express because I have heard that aero ports perform much better than regular ports or slots. The manufacturer for infinity recommends a 2 cubic foot enclosure with a port tuned at 30 Hz. I used a calculator to determine how to get 30 Hz with a 3.0 cubic foot enclosure. All I have to do is cut the aero port shorter to get the tuning frequency the same as I would for a 2.0 cubic foot enclosure. Precision port says that with their aero ports, you want to keep it a minimum of one port diameter width away from any walls for best results. With a 2 cubic foot enclosure and a 12 inch sub, doing that is impossible. Which is why I want to make it a 3 cubic foot enclosure so I can give the aero port enough space on all sides of it. Since it is still tuned at 30 Hz, will it make a difference of its 2 cubic foot or 3 cubic foot? Because overall, the tuning frequency is still the same right?

  • Karl from Madera

    Posted on 2/21/2017

    Is it ever a good idea to mount an amplifier directly to a sub box?

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    Alexander Hrabe from Crutchfield

    Posted on 1/16/2017

    Angel, that information may be in your user manual, but your best bet will be to contact Skar Audio directly at (888) 501-7527.

  • Angel from Hobbs

    Posted on 1/14/2017

    How can you tell if you can put a certain subwoofer in a bandbass inclosure EVL-12 | 12" 2,500

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    Alexander Hrabe from Crutchfield

    Posted on 11/10/2016

    Paul, changing the port diameter or length will impact the sound of your sub. To get the best performance from your sub, follow the manufacturer's suggestions for port size, and if you're looking to craft a very specific sound, their tech support will be the best resource.

  • Paul

    Posted on 11/5/2016

    Hi I had a quick question. Does making the port smaller/bigger just amplify the difference between a ported or sealed box? Fox example if I make the port just a bit smaller then recommended will it have tighter clearer bass? And vise versa for if I make it larger? Thanks

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    Alexander Hrabe from Crutchfield

    Posted on 9/9/2016

    Barrito, check the manual for the ideal dimensions for your subwoofer or you may even want to consult the manufacturer's tech support before beginning. Be sure to take accurate measurements of the space you'd like to use as well.


    Posted on 9/8/2016


  • Commenter image

    Alexander Hrabe from Crutchfield

    Posted on 8/29/2016

    Jesse, it sounds like you're in looking for a ported or bandpass box, but give us a call for the best answer. There are a lot of factors at play, and an advisor will be able to talk through all your needs.

  • Jesse from pikeville, ky

    Posted on 8/27/2016

    I like a deep bass that I can really feel, which would be the right kind of box for that?

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    Alexander Hrabe from Crutchfield

    Posted on 8/26/2016

    Jesse, there's no right answer. It's a matter of preference because each style box will give you a different kind of sound as described above. So, the question becomes: how do you like your bass? Once you decide on that, an advisor will be able to give you a recommendation. Give us a call!

  • Jesse from pikeville, ky

    Posted on 8/25/2016

    Should I use a bandpass, sealed, or ported box for my 15 inch kicker cvrs?

  • Jay from Port saint lucie

    Posted on 7/27/2016

    I have an 8 inch kicker free air subwoofer rms 200watts mounted to the rear deck of my car. Its being pushed by a kicker 300 watt rms amp. My question is to get more bass out of it should i build an enclosure around that sub directly underneath the rear deck to seal it in or should i step it up a notch and get the kicker 8 inch sub that is 300 watts rms and being that its not a free air sub, build the enclosure around that. I have kids so i use my trunk regularly so using thst back deck is the better option for utilizing space. Thanks in advance

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    Alexander Hrabe from Crutchfield

    Posted on 7/25/2016

    Dan, I've passed your question along to our sales team for the best answer. An advisor will contact you soon to help you find the perfect solution.

  • Dan from Brentwood CA.

    Posted on 7/24/2016

    I am putting together a sound system for my boat. I am trying to figure out a better solution than a free air sub that seems the norm. I have an engine compartment with open but divided storage. The side gunwales are open to this compartment. Approx 10in oval port's . If I place a sub box firing to the rear, will this sound travel through the open gunwales. Will this be like a huge speaker box. Will it even sound good?? Was wanting an opinion before I buy the JLaudio 112 HO W6V3 loaded box.

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    Alexander Hrabe from Crutchfield

    Posted on 7/8/2016

    Kevan, I've passed your question along to our sales team. An advisor will contact you soon to help find the right sub for your truck.

  • Kevan from Fenton

    Posted on 7/6/2016

    The box I am looking at for my truck is pretty small only about .60 airspace for the sub and it it holds 2 ten Inch subs. This will be going behind the rear seat of my 2002 F150 supercrew. The mounting depth is small also. The mfg said with the extended 5/8 mounting depth option I could make a Kicker comp 10" work but it would be a really tight fit. What subs if any do you carry for this box? Can you help? I am trying to avoid spending $ 350 for just the single 10" mtx enclosure for my truck.

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    Alexander Hrabe from Crutchfield

    Posted on 6/3/2016

    Nathanial, unfortunately, we don't have a design you could use. Given your parameters, you may need to experiment and innovate. Sounds like a fun project. Your best bet is to contact your sub manufacturer and consult with their tech team for dimension requirements, and then modify from there.

  • Nathanial

    Posted on 5/24/2016

    I am looking to make a bandpass box for 4 or more Re SeXv2 12D4's, but I don't know what frequencies those boxes can handle. I want to tune the box to be able to play +20hz, but I also want to play higher notes as well (50-80hz). I know a regular ported box could do that, but I want a ton more boom with those 30-60 hz range and I want to be able to get a ton of those +20hz as well. Is any of this possible? And would you possibly have a box design I could use?

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    Alexander Hrabe from Crutchfield

    Posted on 5/6/2016

    Donny, check the manual for the ideal dimensions for your subwoofer or you may even want to consult the manufacturer's tech support before beginning. Be sure to take accurate measurements of the space you'd like to use in your vehicle, then follow the steps outlined in this article if you're building your own box.

  • Donny Casarreal from Fontana ca

    Posted on 5/6/2016

    I have 2 12 Jlaudio w6v2 subwoofer for my 1995 Chevy Impala what kind of box would be the best for it

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    Alexander Hrabe from Crutchfield

    Posted on 4/20/2016

    Terrence, we'd need a bit more information to confirm that match, but this article is a great guide to be sure. As far as the enclosure style, that will come down to your preference in bass.

  • Tmoney from high springs

    Posted on 4/17/2016

    I have two aucostic 15 and two 1500 watt boss amps the RMS on speakers are 300 and the RMS specks on the ams 200-300 anyway I was wondering if this is a good fit and should I use a double vented enclosure or single

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    Alexander Hrabe from Crutchfield

    Posted on 4/8/2016

    Brett, typically, folks opt for one or the other, since each has a distinctive quality (here's a little more info on that), but if you'd like to combine those sounds, you could.

  • brett

    Posted on 4/6/2016

    i have a sealed box for 3 10" polk db1040dvc subs. Would it be possible to get both ported and sealed sound quality by putting ports in two of the subs and leaving the one in the middle sealed or is that unrealistic?

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    Alexander Hrabe from Crutchfield

    Posted on 12/21/2015

    John, while two subs wired to two different amp channels are indeed technically playing in stereo, you're not likely to hear any stereo separation with bass frequencies, especially when the subs are sitting right next to each other. Most people choose instead to bridge the amp channels into a single output, which will give the subs more power than the stereo connection.

  • John from Cincinnati

    Posted on 12/19/2015

    Do subwoofers play in stereo. So using 2 subs on the proper 2 channel set up left and right. Is that stereo

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    Alexander Hrabe from Crutchfield

    Posted on 11/30/2015

    Mason, I've passed your information along to our sales team for the best answer. An advisor will contact you soon to help you find the enclosure that works for you.

  • Mason Schneider from Caldwell

    Posted on 11/29/2015

    I have 1 10 inch shallow mount pioneer sub. I'm going to install it under the seat of my old pickup. What type of box would work best for me.

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    Alexander Hrabe from Crutchfield

    Posted on 10/22/2015

    Guillermo, I've passed your information along to our sales team. An advisor will contact you soon to help.

  • Guillermo from Mesa

    Posted on 10/21/2015

    Hi, i been wondering what to do with my system, i have 2 12" kicker solo x i want em to sound as loud as possible but my trunk isnt that big, i dont wanna spend a bunch of money in a custom fiberglass box what could i do?

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    Alexander Hrabe from Crutchfield

    Posted on 8/21/2015

    Erich, all of our dual enclosures feature an internal wall to ensure each sub gets the right amount of air space and to give the box a stronger, sturdier structure.

  • Erich from Pretoria

    Posted on 8/21/2015

    Hi, I wondered what was best between a double/dual box setup? Both in one box but there is a split between them so they are actualy seprate or should they just be in one open box?? I have two Rockford Fosgate R2D2-12 subwoofers and just wanted to find out before i install them.

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    Alexander Hrabe from Crutchfield

    Posted on 8/17/2015

    Dennis, the size of port you need depends on the cubic volume of your box and what frequency you're trying to tune for. You can check the subwoofer owner's manual for suggestions, but searching the internet for "tuning port calculator" should point you to a couple of places that'll help you figure it out.

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    Alexander Hrabe from Crutchfield

    Posted on 8/17/2015

    Devil Dawg, that's a great choice for a sub. Your choice of enclosure comes down to what you're looking for in you bass. As this article points out, a sealed enclosure will give you tighter, more accurate bass, while a bandpass box will put more boom in your bass.

  • Devil Dawg from Spring Hill

    Posted on 8/15/2015

    How will a JL Audio 13W7 do in a sealed enclosure vs a bandpass enclosure?

  • Dennis kinnear from Cape Town

    Posted on 8/15/2015

    If my box is 450mm wide, what length round port can i use

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    Alexander Hrabe from Crutchfield

    Posted on 8/10/2015

    Ethan, that might be a bit too small. Take a look at the owner's manual and follow their recommendations for the best sound.

  • Ethan

    Posted on 8/8/2015

    I am planing on buying two kenwood 12s. Would a 1.6 cu ft ported box sound good? The sub calls for a 2.0 cu ft ported box.

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    Alexander Hrabe from Crutchfield

    Posted on 8/3/2015

    Tim, check your manual for the ideal specs for an enclosure. If they're not listed there, the Boss support site should be helpful, or give their tech support a ring.

  • tim from columbia, tn

    Posted on 8/1/2015

    what is the best design and dementions for 15 inch. boss chaos series subwoofers??

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    Alexander Hrabe from Crutchfield

    Posted on 7/27/2015

    Brian, awesome purchase! Unfortunately, we don't carry boxes for the Solo-Baric series (only pre-loaded boxes). If you want to build your own box, we can help you with that. Otherwise, give Kicker a call for a recommendation at (405) 624-8583.

  • brian from haines city

    Posted on 7/26/2015

    What box will my 2 15" L5 kicker solo Baric sound best !

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    Alexander Hrabe from Crutchfield

    Posted on 7/23/2015

    Kevin, check out our selection of enclosures or if you're interested in building your own box, this article will help.

  • Kevin McCarthy from detroit

    Posted on 7/22/2015

    I need a box made for 2 10s (circle ) and 1 15 square

  • eric from harvey

    Posted on 7/18/2015

    I have a ported double chamber box and two p2d4 12" Rockford fosgate subs with a Rockford fosgate t600-2 amp. I know most punch eq and bass boosters are speaker killers so I have it at minimum on amp and -5 on my deck. I have a factory infinity audio in my 2011 Hyundai genesis coupe... and one of my subs magnet cracked in half... I took it out because it was blown and when I took the sub apart the magnet was in half and the pieces of it were rubbing on the coiled wire in the sub so its shot. I am still pushing the one sub with all guts that would rattle the other taken out and put back in place to keep the sub box enclosed... wondering what my best option for premium bass for rap and techno would be without replacing the factory motor... has automatic climate control so I wont remove it