Sealed or ported

The differences in subwoofer enclosures


Buck Pomerantz

Buck Pomerantz was born and raised in Philadelphia. His parents bought their first television set when he was born. He figured out how to run it by the time he was two. Besides athletics, his formative interests included electronics, amateur radio, music, and stage crew work. He got his BA in writing from Brown University. Then he joined a rock 'n roll band as their soundman and moved to Charlottesville, Virginia. After that venture failed, he spent time in Boston, New Orleans, and Berkeley. He worked in a music store in Austin manufacturing, installing, repairing, and operating sound systems for recording studios, clubs, and bands. He moved back to Charlottesville, ran a little recording studio and finally joined Crutchfield as a copywriter. He has 2 grown children and 3 grandchildren, but after a good nap he can still rock out.

More from Buck Pomerantz

Alpine subs in Sound Ordnance Ported and Sealed Boxes

Alpine Type R subs in Sound Ordnance ported and sealed boxes

The only way you're really going to get full, rich-sounding bass from your car stereo is to put in a subwoofer. Adding a sub to your system will greatly improve the fun and impact of your music, no matter what kind of music you listen to. Generally speaking, there are two bass camps—those who like it “tight” and those who like it “boomy.” The style of bass you prefer ultimately depends on your personal taste—and can even vary depending on the style of music. To demonstrate this, we brought a small group of Advisors into the Labs, played different kinds of music through the same component subwoofer loaded in two different kinds of enclosures, and had them vote for which sounded best to them for each song.

Camp A: I want to hear bass, not thunder

Each beat in a tight bass setup plays crisply, accurately, and with no ringing after it hits. The easiest way to achieve this is with a sealed sub box. The sealed air inside one of these enclosures acts like a shock absorber, smoothly modulating the subwoofer cone's back and forth motion, so all the notes get produced evenly. Sealed subs are generally more compact than ported subs, so they fit in more vehicles.

Sealed sub box

Sealed air moderates the cone’s motion.

Another effect produced by the air pressure behind the cone is that it takes more power to produce the same volume as it would in a comparable ported box. What a sealed sub rarely does is roar, thunder, or boom. That's because a sealed sub has very flat frequency response and tends to play tight, full bass that provides a level low-frequency foundation to your music.

Camp B: I like it loud

Boomy bass has more punch and reverberance in each of its beats. This is easily attained, without using any equalizer or processor, with a ported sub box, where the cone has greater freedom of motion. The port redirects sound from the rear of the cone and adds it to the sound coming from the front, making the bass louder. This increase in efficiency lets you use a smaller amp than you would need with a comparable sealed box to play at the same volume. Another long-term advantage of choosing a ported enclosure is that the air flow keeps the subwoofer cooler, so it will live longer than it would in a sealed box.

Ported sub box

Air flows in and out of the port.

Another reason ported subs hit so hard and deep is that the air flowing in and out of the port creates an audio effect like that made by a whistle or blowing across the mouth of a bottle, and that tone adds to and strengthens the note the cone plays. Ported enclosures tend to be much larger than a comparable sealed enclosure, so space availability becomes a factor when deciding on a ported sub.

Which sub enclosure do you prefer with different kinds of music?

Crutchfield Advisors often ask their subwoofer customers what styles of music they like, so that they can recommend a sub that will match the customer’s tastes. The panel of Advisors who participated in this demonstration were all eager to listen to the two subs as part of their ongoing efforts to improve the quality of their advice to customers. The results, and some of their comments, are charted below.

The lineup of listeners

The small crowd consisted of Advisors Duke (who, at the time, had been here for almost 5 years), Dolly (4 years), Daniel (almost 2 years), and Dylan and Larry (1 year each). Travis, a Graphic Designer at Crutchfield for over 12 years, decided to join the fun, too.

The listening setup

We loaded Sound Ordnance sealed and ported enclosures with identical Alpine 10" subs, and powered them with the same mono amp mounted in our car listening room. The only change that occurred, when we switched between the subs every 10 seconds, was the kind of sub enclosure being played. We played various kinds of music both with and without full-range speakers, so our listeners could judge the sound quality of the bass, with minimal influence by the change in volume due to the different efficiencies of the subs.

(We didn't play any subwoofer mounted in an "infinite baffle" or "free air" setup, or in a bandpass enclosure, because these hybrid systems usually need sound processing to sound right, and would be difficult to compare fairly in the Labs.)

Travis and Dylan in the Labs

Two of our listeners, Travis and Dylan, compare notes in the Labs

The Votes Sealed box Ported box
Pop 3 3
Rock/Alt 3 3
Classical 3 1
R&B/Rap 1 5
Electro/Dance 2 4

Listener comments

  • Pop: “The ported had more punch but sounded muddy. The sealed sounded better to me on this one.” – Travis, Designer
  • Rock/Alt: “The sealed sub delivered more emphatic bass. The ported was louder, but it got away from the music.” – Duke, Advisor
  • Classical: Two Advisors heard no difference for the cello-heavy piece we chose to play.
  • R&B/Rap: “The bass definitely sounded more natural with the ported box for the Rap.” – Dolly, Advisor
  • Electro/Dance: “The ported sub sounded and felt better to me for this song. It accentuated the quality of the bass.” – Larry, Advisor

Some thoughts

Daniel, Advisor: “The sealed sub was definitely tighter and more accurate which some may prefer for listening to certain styles of music, like maybe Country or Classic Rock. I liked the ported mostly for the heavy bass.”

Dylan, Advisor: “When I preferred the ported it was because it seemed to fill out the music with something that was missing from the song itself. When I preferred the sealed it was because of the quality of the bass. It would hit on every note, keep a perfect beat, and make the song flow more appropriately.”


The mixed reactions and the tie votes reinforce the notion that it basically comes down to taste in music. “Accuracy” and “tone fits the music” were two sound qualities cited by Advisors who liked the sealed sub for the Classical piece. But those same Advisors thought the sealed sub’s sound did not fit with the Rap and Dance songs—it depended on the quality of the bass in the songs themselves.

So, when choosing the subwoofer and enclosure for your system, don’t forget to consider what sound qualities you like in the music you listen to, so whether poppin' loud or humming low, you’ll end up getting the kind of bass you want.

Watch the video:

  • Randy Evans from Louisiana

    Posted on 6/17/2015 12:20:55 PM

    I'm building a sub box with 3 subs 1 12inch and 2 10inch. I wanna have the 12 sealed and the 10's ported is this a good plan?

  • Buck Pomerantz from Crutchfield

    Posted on 6/17/2015 1:00:51 PM

    Randy, Most people prefer either the tone of a sealed subwoofer or the tone of a ported sub. That certainly doesn't mean you can't run both at the same time - you can. The resulting mixture of tones may sound muddy, but you might like that.

  • John from Hastings, UK

    Posted on 7/12/2015 1:00:59 PM

    Hi, I'm planning the sound system for my camper van and have decided to use 4 x Vibe blackdeath qb69 and not use a sub at all. I like quite a mix of music mainly rock and dance and I am struggling to decide if I should port the enclosures or not also I am struggling to to work out the appropriate port sizes etc as they are full range speakers, any advise would be greatly appreciated.

  • Buck Pomerantz from Crutchfield

    Posted on 7/13/2015 3:38:18 PM

    John, Car audio speakers are designed to work best when mounted so the sound from the back of the speaker is kept entirely separate from the sound coming from the front. A ported subwoofer uses the port to direct some of that rear sound to combine with the front sound, increasing the bass. If you were to mount those speakers in a ported enclosure, the bass would probably overwhelm the other frequencies, making it all sound muddy and indistinct. If you want enclosures for those speakers I recommend sealed ones.

  • alex from santa fe,nm

    Posted on 7/31/2015 10:59:28 PM

    Would a 15" subwoofer fit in a 12" subwoofer ported box

  • Buck Pomerantz from Crutchfield

    Posted on 8/2/2015 11:33:34 AM

    Alex, An enclosure designed for a 12-inch subwoofer will probably not work very well with a 15-inch sub. But if the enclosure has enough depth, and you can enlarge the cutout hole in the baffle, you could probably get one in. Ported boxes are tuned by their internal volume and port length and area, so yours may not be very well tuned for bass after the modifications.

  • Riley

    Posted on 8/22/2015 2:29:05 AM

    If I were to listen to all types of music, would it be possible to build a ported sub box that I could plug the port to make it technically sealed? My thinking would be that I could have the box ported or sealed based on what type of music I am listening to for each day. Would this be a bad idea structurally? Would it actually work? This is all assuming the box is built to be within the parameters of the sub's cubic feet requirements for each type of enclosure.

  • Buck Pomerantz from Crutchfield

    Posted on 8/24/2015 10:14:35 AM

    Riley, I don't see any reason not to try it. Although you might find you prefer one style of subwoofer over the other for all your music.

  • David from ashland city

    Posted on 8/28/2015 11:10:05 PM

    yes I just installed all new speakers 2x 6x8 in doors and 2x 6x9 in back in my crown vic i see what looks like a 10" hole for maybe a factory sub (just guessing) but if I was to mount a sub in that hole with free space to the trunk is that a bad idea? I listen to classic rock for the most part and my head unit is a sony 220 watt driving my 4 speakers and was thinking to add an amped sub as I said any thoughts would be appreciated

  • Buck Pomerantz from Crutchfield

    Posted on 8/31/2015 10:31:52 AM

    David, What you describe is called an "infinite baffle" arrangement for a subwoofer, and it'll work fine, especially with a subwoofer designed for that use. Your rear deck serves as the baffle that keeps the sound from the rear of the cone (in the trunk) from interfering with sound coming from the front (into your car). Unfortunately, because of the technology of the day, you will find that Classic Rock contains very little subwoofer content.

  • David from ashland city

    Posted on 9/2/2015 12:16:38 AM

    so you said classic rock had very little sub content so even a sealed sub would help me so if I want a better sound would a amp help me because my unit is 220 watt system would I get a better sound that way, even the 220 watt does sound very good just don't want to waste money just want to get the best sound I can

  • Buck Pomerantz from Crutchfield

    Posted on 9/2/2015 10:20:10 AM

    David, We recommend that if you're using an aftermarket receiver get a subwoofer amplifier with about 200 to 300 watts RMS output.

  • jimmy from miami

    Posted on 9/20/2015 9:01:50 AM

    I have a 2400watt amp pushing my 2-12 in a sealbox in my G35 sedan i was wondering if a ported box will be a bit louder some one told me that sealed box are better in sedan vehicles and that ported box is not good for sedans, that it works good for SUVs and hatchback cars is that tru ?

  • Buck Pomerantz from Crutchfield

    Posted on 9/20/2015 3:40:39 PM

    Jimmy, Changing from a sealed to a ported enclosure while keeping the same amplifier will gain you a little loudness. As for suitability in different types of vehicles - I think what you're referring to is the facts that sealed boxes are smaller and fit in smaller vehicles like sedans, and ported boxes are larger and will only fit in vehicles with larger interiors.

  • Rick from Alexandria

    Posted on 11/1/2015 11:15:49 AM

    Hi, just wondering what size of sealed enclosure you would recommend for a 1000wattRMS type R subwoofer. I listen to mainly hip hop but I don't like too much of a loud bang in my bass, which is how it currently sounds with my ported box. I'm looking for quality in the note over a car rattling thunder.

  • Buck Pomerantz from Crutchfield

    Posted on 11/2/2015 1:40:01 PM

    Rick, As far as I can tell, Alpine makes eleven different Type R subwoofers, and what size sealed enclosure each works best in depends on the sub's size and other criteria. To find out the best box for your sub, go to Alpine's website and look up the specs for your particular model. You will also find there links to the owner's manual for each subwoofer that gives even more detail about recommended box sizes.

  • Devin Richard from West Simsbury

    Posted on 11/16/2015 12:05:00 PM

    what if i were to stick like a shirt or something in the port to give it like a feel of a ported and sealed sub-woofer would that work or would that make it sound worse? i really dont know if i want a ported or a sealed box

  • Buck Pomerantz from Crutchfield

    Posted on 11/16/2015 3:22:37 PM

    Devin, Usually a component subwoofer will require a very different sized sealed or ported enclosure to sound its best. For example, Kenwood's KFC-XW100 sub works best in a 0.65 cu. ft. sealed enclosure or a 1.2 cu. ft. ported one - almost 100% larger. You may be able to get a general sense of the differences in sound between a sealed and ported box by blocking and unblocking the port with a panel or something, but a shirt probably won't be air-tight enough for you to hear much difference, except maybe a muffled sound coming out of the port.

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