Setting up my home theater system was an act of love. I carefully researched and selected every single element along the way. After all, as I am sure many of you agree, a full home theater system can be a substantial investment and I did not want to waste a cent. At first, I considered investing in minimal equipment – a great television, some rear speakers and a Soundbar. However, once I installed my components I noticed those deeper tones appeared lost or muddied. The importance of the subwoofer then became more apparent. My first venture into the subwoofer world was overwhelming. There are just so many options! But, with so many different types, where do you start?
So what makes sealed, ported, and bass radiator subwoofer boxes different? The primary differences between these subwoofers stem from their construction. Sealed subwoofers are entirely enclosed. Ported subwoofers, on the other hand, have a small vent strategically cut into the front. Bass radiator subwoofers actually include features from both and attempt to bridge the sound gap.
- Typically smaller than ported versions.
- Richer sound at lower octaves.
- Smoother transient responses.
- Almost entirely unaffected by external factors, like humidity.
- Quieter than ported models.
- Poor efficiency; a powerful external amplifier is likely a must.
- Packs a bass punch.
- Needs less power and equipment.
- Distortion is reduced.
- Sound can escape through the vent.
- More sensitive to humidity and other factors.
- Requires solid, exact construction.
Bass Radiator Subwoofers:
- Middle-ground between sealed and ported models.
- Protected from external factors, like humidity.
- Similar in size to a compact, sealed subwoofer.
- Often the most expensive option.
- Requires solid, exact construction and includes more parts than other types.
For those who want great bass, the sealed versus ported versus bass radiator subwoofer debate is ever ongoing. Below, I help you cut through the bull to get down to the real pros and cons associated with each type.
Sealed Subwoofer Box
Acoustic suspension, also known as “sealed” or “closed”, subwoofers are one of the most common subwoofers on the market today for both home theater and automobile use. However, before I get to the pros and cons, let us take a look at how these subwoofers work.
Sealed subwoofers are just that. They are speakers that are embedded in a sealed box. In doing this, the pressure from the box helps to restrict vibrations. Sealed subwoofers include a single active driver that helps funnel the sound waves being bounced off the back of the box through the speaker cone. (In the world of electronics, “active” typically refers to a driver that is powered.)
Sealed subwoofers are typically smaller than the ported version. This makes them ideal for small spaces, discreet placement, and minimalistic décor. As I said earlier, the compressed nature of the enclosed box restricts vibrations. This helps to prevent the octave vibrations from diluting as they are pushed through your speaker. This also helps with creating smoother or “tighter” transient responses between your different tones. This means the sound rolls between tones, without fraying or becoming muddy. Moisture is seldom good for electronics and a subwoofer is no exception. Because it is fully enclosed, sealed subwoofers are almost entirely and naturally insulated from humidity and other factors.
Sealed subwoofers are not as loud as the ported ones due to the way the enclosed box restricts vibrations. In addition, while I have noted that sealed subwoofers are smaller than ported, this does not mean they are as efficient. In fact, it is quite the opposite. The restricted nature of the sealed subwoofer makes transient responses smoother, but it also wastes the vibrations that come off the rear side. This means you need to push more power into the subwoofer before it can provide the same loudness as a ported version. While sealed subwoofers come with internal amplifiers, you will likely need to add a more powerful external one for maximum range.
Ported Subwoofer Box
Bass reflex subwoofers are another of the more commonly used types. Frequently referred to as “ported” or “vented”, these subwoofers, these models are larger than the sealed versions.
Ported subwoofers operate similarly to the sealed versions. However, these subwoofers include an open, vented slot that works with vibrations to produce window-shaking bass tones. Like sealed subwoofers, ported ones include a single active driver and a lone cone. These subwoofers pack a punch thanks to the vent, which allows the cone more freedom to vibrate. (Although you should note, improper vent sizes and mismatched box dimensions and cone shapes can lead to imbalanced sound.) To allow for this vent, ported subwoofers are some of the largest types available today.
The sound delivered by a ported subwoofer is much louder than that of a sealed model, without having to use the same powerful amplifier. In fact, a properly manufactured ported subwoofer may not even need an equalizer or digital processor. Loud tones often become slightly distorted as the volume increases. Because the vent allows some sound to escape, a ported subwoofer helps to reduce distortion.
The vent may help reduce distortion, but it comes at an expense. In some cases, the sound waves coming through the vent may be audible; the escaping sound coming from the vent can be distracting. In addition to this, the vent leaves an opening for external factors, such as humidity, to penetrate into the device. This can cause your subwoofer to die prematurely depending on the environment it is used in. (In fact, ported subwoofers are more sensitive in general. Driver fatigue, for example, will affect a ported subwoofer before it will disturb a sealed one.) Ported subwoofers need to be solidly constructed. Failure to do so can leave your ported subwoofer far from ideal, diluting sound instead of reducing distortion, and muddying your tones at high sound levels.
Bass Radiator Subwoofers
Bass radiator subwoofers are actually more commonly referred to as passive radiator subwoofers. These subwoofers are almost a middle ground between the sealed and ported versions. Both sealed and ported models have an active driver attached to their sound cone. However, a passive radiator subwoofer includes an active (powered) driver, as well as two passive (non-powered) ones. Since they are not powered, these two passive drivers vibrate back and forth with the expanding and compressing air within the enclosed subwoofer box. This helps to reduce resonance and create smoother tones without venting any of the vibrations.
A bass radiator subwoofer appears more similar to a sealed version in that it is fully enclosed. As with the sealed subwoofer, this helps protect it from external elements, like humidity. However, the passive amplifiers make it sound more like the ported subwoofer. Additionally, bass radiator subwoofers are more compact, like the sealed models. This means bass radiator subwoofers can accommodate both large and small spaces alike.
A bass radiator subwoofer is often more expensive than sealed or ported models of similar quality. Additionally, because of the two passive amplifiers, a bass radiator subwoofer introduces additional components that you need to worry about. Because of this, most audiophiles urge you to consider the sealed or ported subwoofers instead.
The Bottom Line: Which Subwoofer Box is the Best?
It is always important to really dive into the reviews left on any electronics you are looking to invest in. However, given the pros and cons above, finding the right subwoofer for your needs may be easier. Let us recap!
Sealed subwoofers are often the best choice for those who enjoy critical music applications. Compact, the deep tones it reproduces make it an ideal fit for those who have a small to medium sized room and want to boost their home theater’s sound capabilities. You will need to make sure that your amplifier has enough power to ensure a sealed subwoofer works. However, many audiophiles find this investment inconsequential once they hear those deep, rich tones. For those who like to hear distinct tones without rattling their television screens, a sealed subwoofer is a great option.
Ported subwoofers are a solid investment for those who enjoy turning the volume up! Because of their vented nature, almost any amplifier can support the use of a ported subwoofer. If you want to fill a room with sound, regardless of size, ported subwoofers are the way to go. Make sure you opt for a solidly constructed model and protect it from humidity. If you want your home theater to sound just as grand as the IMAX Theater, invest in a quality ported subwoofer.
Bass radiator subwoofers merge technologies from sealed and ported versions and introduce additional passive drivers. They offer sound quality similar to a ported version, but from the compact size of a sealed subwoofer. While some prefer these subwoofers, they are often more expensive and have additional components that may become damaged. If you are looking to invest in a bass radiator subwoofer, it is essential that you scrub their reviews vigorously to ensure you are buying a quality product.
Thursday 25th of August 2022
This information is misleading and inaccurate.
For example: A sealed sub is NOT "richer" at lower octaves. Instead, a sealed sub will technically be able to reproduce lower frequencies without exceeding its mechanical limits while a ported sub will "unload" below its tuning. Typically the low notes where a ported sub will start to unload will be barely audible from a sealed sub anyway so it's a huge stretch to say that a sealed sub is richer in the lower octaves.
Another example: You listed sound being able to escape from the port as one of the cons of the ported design. This sounds silly because it is literally the point of the port. In fact a con of the sealed design is that half of the sound energy is essentially lost in the sealed box compared to a ported design. This is why sealed subs are less efficient.
Another example: A passive radiator is in no way a middle ground between sealed and ported. They do NOT "combine the technologies of both." Passive radiator designs have the same alignment as ported. Passive radiators function essentially the same as ports but require less space since they are tuned by adding or removing mass instead of making ports longer or shorter. They offer a solution when space is limited. Their cons include a slightly steeper roll-off below tuning and subsequently a higher F3 compared to ported enclosures that utilize the same volume of air for resonance, they are slightly less efficient overall due to mechanical losses, and they are (as the article correctly points out) expensive compared to ports.
I am reading through the rest of the article and quickly realizing that there are too many issues with the way this information is being presented. I honestly think it should be re-written.
Tuesday 19th of April 2022
Very helpful. Thanks, Jonah.
Thursday 17th of March 2022
I use to have an rsw-10d passive radiator subwoofer copled to 6-1/2 inch bookshelves and it blended seamlessly with fast transients and good impact and thump at lower frequencies. It was my nirvana until amp gone bad… people always talk about ported vs sealed vs passive radiator sw options but tend to overlook a bit the room size (always recommended a ported one for bigger rooms whyle it is possible to use sealed ones if you double/quadruple the quantity to compensate) and a sealed for smaller rooms without questioning how powerfull your front channels and speakers are. If you have a respectable power in front channels at 60-80 hz range, you’d be fine with ported, specially if it is for HT use. If you listen music, you definetly need a sealed/passive radiator if your frontal speakers do not have much power in that range or you will loose transient speed and definition in upper bass notes. It’s quite simpler when you know what you need, know what to match and do your homework. I see lazy people buying good and expensive portes subwoofers with a bad match of equipments, positioning and room and blaming them. If the rest of the system isn’t that powerfull, a pair of cheap sealed subs might just fill the bill with glory after some receiver DSP equalization…
Friday 18th of December 2020
Nice review. I just bought a Dayton Audio Sub 1000 for $145 that has a great 10" treated paper cone driver and a 100 watt Plate amp with all Optional inputs and I'm taking it apart to create my new C/S 10" Mono Powered Subwoofer. My old non powered stereo sub is a tank! It weighs like 75 lbs if not more. the side facing the wall is only a 10" Polk driver used as a passive radiator but the side facing the open air it's a full 10" Sub Woofer with a top mounted 100 watt mono Class D amp. This sub should sound really great and this for only $145. Plus the Polk driver pulled from a dead Polk PSW 10" powered sub. I have to tell people DO NOT BUY THE POLK PSW10 powered sub. Its horrible amounts of front port noise are horrendous. Just buy the Dayton Audio Sub 1000 10" for $145 or the Sub 1200 for $155. For the money you can't beat these subs. However, the Emototiva Airmotiv 8" 200 watt powered sub is great for music. For $320 including tax you get a full 200 watt amp with a nice fast 8" main subwoofer and a front 8" passive radiator. Great reviews for music playback with zero port noise.My C/S 10" should give a ton of very clean low bass in the new enclosure that is so very solid. They simply don't build subs like this tank anymore.
Friday 5th of June 2020
I found it very helpfull. Thank you very much.