The holidays are fast approaching, and for many AV enthusiasts that means it's a time to think about the next big upgrade to their system. If you already own a good AVR and are happy with your speakers, one of the best paths to improved system performance is to add or upgrade a subwoofer or two (or three, or four).

Accurately reproducing deep bass at visceral volume levels is a crucial component to achieving the sense of escape that comes with suspension of disbelief. However, subwoofers span a bewildering gamut of price points, designs, and capabilities, from the familiar "cone in a cube," to infinite-baffle systems, to in-wall subwoofers, to tapped horns, and even designs that use a fan.

While I'd love to cover all those options in one article, the focus here will be on standalone subwoofers—the most common type. Whether you're looking for your first serious sub or are considering an upgrade to the system of your dreams, here's a handy list of things to think about when you're shopping for a subwoofer.

1. One Subwoofer or Multiple Subs?

- Most experts agree that using multiple, well-placed subs can result in more even bass response throughout a room than one sub can achieve. I recommend spending some time in the Subwoofers, Bass, and Transducers forum talking it out with AVS forum members who have experience putting together multi-sub systems.

- Many people have space for only one sub. Others have permission to purchase only one subwoofer. In these instances, get the best one you can afford.

- In a system with two or more subwoofers, the overall performance of the system is more important than the performance of each individual sub. With multiple subs, you might not need as powerful a model as you would with only one.

- Every time you double the number of subwoofers in a system, you increase output by 6 dB (assuming they are playing at the same level). As a result, you can decrease the overall subwoofer level, and each one needn't work so hard to achieve a given volume in the room.

- With a single subwoofer, you can use EQ to optimize bass response for one seat or a small area, but not for a larger audience such as a home theater with multiple rows.

- If you have a home theater with multiple seats and rows, you'll get the best bass response using multiple subwoofers.

- If you deploy multiple subs, they don't all have to be the same model. However, they should be similar in terms of capability.


2. Sealed, Ported, Passive Radiator, Horn-Loaded, Infinite Baffle

- Sealed subwoofers are the simplest design, typically consisting of either one or two drivers mounted in an airtight enclosure.

- If you're looking for compact subwoofer, sealed is the way to go.

- Ported subwoofers rely on a tuned port to amplify bass response at a specific resonance frequency.

- Some ported subs include more than one port, and you can put a plug in one or another port to change the tuning.

- Passive radiators are drivers with no voice coil; they vibrate in response to changing air pressure within the enclosure. They behave similarly to ports, converting energy that would otherwise be lost into extra bass output at whatever frequency they are tuned to.

- Subwoofers that feature passive radiators tend to cost a bit more than similar sealed or ported subs.

- Inexpensive ported subwoofers tend to have high tuning frequencies that compromise performance; if your budget is low, it's probably better to stick with sealed subs.

- Some sealed subs use multiple drivers in a force-cancelling configuration where the cones are facing in opposite directions. This is a very effective design for getting a lot of clean output from a small box, but models that implement it tend to be pricey.

- Large, ported subwoofers often represent the best bang for the buck for home-theater applications.

- Horn-loaded subs place a horn in front of the driver and offer high sensitivity, but they take up quite a bit of space.

- Infinite-baffle subwoofers consist of raw drivers that are typically installed in basements or attics and use that space as a giant enclosure. They can also use an adjacent room to that effect. This type of system can generate bass that is very clean and deep, but it can be very expensive.


3. Output and Low-Frequency Extension

- Output refers to how loud a subwoofer can play, measured in dB SPL (decibels sound pressure level).

- Bass extension refers to the lowest frequency a subwoofer can reproduce at a certain level, measured in Hz (hertz).

- Peak output, continuous output, and low-frequency extension are key specs in determining if a subwoofer is right for your application.

- Typically, humans can hear down to 20 Hz, but subwoofers that play clean down to this frequency are not cheap.

- 16 Hz is the lowest frequency used in classical music; subwoofers that can play clean and loud down to 16 Hz are comparatively rare, but the effect they create is awe-inspiring.

- If you use a subwoofer mostly with music, the output and bass extension you need depends on the genres you listen to and the volume level you typically use. Hip-hop and electronic music demand deeper extension than most orchestral, rock, folk, or jazz recordings. Some compact subs can play very deep, just not at earth-shattering levels.

- Many movies, especially action flicks, include lots of very low-frequency content such as explosions, rockets, etc., and these sounds are normally intended to be played pretty loud. For this application, a sub that has low bass extension and high output is ideal, though satisfying both criteria can be expensive.

- Unless you play music and movies at extremely high levels, you'll probably get more satisfaction out of a subwoofer that offers good low-frequency extension but modest output, as opposed to a subwoofer that offers limited low-frequency extension but a lot of output at higher frequencies.


4. Driver and Cabinet Size

- It's easier to get more and deeper bass out of a larger sub. If you have the room, you will get more bang for your buck with large subs.

- Typically, sealed subwoofers are smaller than ported subs.

- The size of the driver is only one factor in how well a subwoofer performs.

- You won't find subs with 18" and larger drivers in stores, but they are available for folks who need massive quantities of bass from online sources and DIY suppliers.

- Depending on the size and shape of your room, it may be easier to fit two or three smaller subs than one large sub.


5. Powered or Passive?

- A powered subwoofer has amplification built-in. Passive subs rely on external amplification.

- The vast majority of manufactured, standalone subwoofers are powered.

- Powered subs typically include controls to blend the sub with the speaker system, such as volume, phase, and a lowpass filter.

- DIY subwoofers are often passive designs and rely on external amplification. However, DIYers can choose to use a plate amp that attaches to the cabinet if they want to build a powered sub.

- Infinite-baffle subwoofers and other types on in-wall subs are typically passive, relying on external amps and DSP to integrate properly with speaker systems.

- Standalone passive subs are more common in the world of pro audio than consumer audio.


6. Features and Controls

- Entry-level subwoofers often offer only one line-level input and a couple of controls such as volume and lowpass filter. Typically, these are found on the rear of the unit where they are hard to reach. Subs with controls on the front panel are much easier to adjust.

- More advanced subwoofers offer features like stereo inputs, highpass outputs, and variable phase control.

- Top-of-the-line subwoofers feature balanced XLR connections that reject noise and are good for long cable runs.

- If you are using a subwoofer in a 2-channel system that does not offer preamp outputs, then you should look for a sub that offers speaker-level inputs.

- Some subwoofers, such as ELAC's S10EQ and S12EQ models as well as SVS Sound's 16-Ultra series, let you control various parameters with a smartphone app; this can be very useful for making adjustments.

- Subs with built-in EQ are recommended for audio systems that don't offer that functionality as part of the AVR's or pre/pro's feature set.

- If your AVR or pre/pro offers sub EQ, you can avoid that redundant feature in the sub itself and potentially save some money.

- MiniDSP makes a series of products such as the miniDSP 2X4 ($105) that make it easy to EQ subwoofers and perform bass management, with very fine control over parameters.


7. Music vs Movies

- Movies tend to be more demanding than music when it comes to the deepest bass frequencies. If you are a home-cinema nut, it makes sense to prioritize bass extension and output above size and aesthetics.

- Ported subs are much more efficient than sealed subs at their tuning frequency. To get maximum bang for your buck in a home-theater sub, look for a ported model tuned nice and low, preferably under 20 Hz.

- There is no such thing as a subwoofer that's better for music or home theater. If it performs poorly in one application, it's sure to perform poorly in the other.

- Some audiophiles reject subwoofers altogether, but it's rare that a properly integrated subwoofer or two won't improve a system's performance.

- Music lovers looking to extend the bass performance of bookshelf speakers may find that a compact sealed sub is all they need.


8. The DIY Option

- Do you have woodworking skills and a desire to take on challenging project? The DIY community on AVS Forum can show you another way to bass bliss.

- Kits make it easy to build your own subs if you don't have woodworking skills.

- The savings of the DIY approach increase when you get into building multiple subwoofers or very large and powerful subwoofers.

- DIY is obviously not plug and play; if you want a subwoofer that works from the get-go, you need to buy something that's already been assembled.


9. Budget and Recommendations

- Subwoofers don't have to cost a fortune, see this list in AVS Forum for a wide variety of subs priced under $300.

- For under a hundred bucks, you can get the #1 best-selling subwoofer on, the Polk Audio 10" PSW10 ($88). Frequency response is specified at 35 Hz to 200 Hz, with a -3 dB point of 40 Hz; that's deep enough to add oomph to bookshelf or satellite speakers. Another inexpensive option is the Monoprice 12" #9723 ($108), which was singled out by as the best budget subwoofer. While you should not expect miracles from an ultra-budget subwoofer, it's surprising how much performance you can buy for around a hundred bucks these days.

- In the zone between $100 and $400, you'll find numerous viable options. The Bic Acoustech PL-200 12" sub ($250) gets mentioned quite often and promises a frequency response from 22 to 200 Hz at a rather low price. The Dayton Audio SUB-1500 15" 150-watt sub ($200) is large and heavy, and it will get you down to 24 Hz without breaking the bank; it too has received much positive feedback.

- The Klipsch Reference 10" R-10SW ($350) offers a frequency response from 32 Hz to 120 Hz (+/-3 dB) in a compact enclosure. Another option under $400 is the Definitive Technology ProSub 1000 ($375), which is often cited as a great performer, even if the specified frequency response from 18 to 150 Hz is a bit optimistic.

- At prices between $400 and $1000, there is an incredible variety of subs in all shapes and sizes. The SVS PB2000 ($800) brings impressive output and infrasonic capability to the table, as does the Klipsch R-115SW ($900), the Hsu VTF-15H MK2 ($900), and the Power Sound Audio 15V ($950).

- The $400-$1000 price range is also a sweet spot for DIY projects and kits; that's a rabbit hole I strongly recommend you dive into if you're interested in getting maximum bang for your dollar; check out the AVS Forum DIY Speakers and Subs section if that sounds appealing. Parts Express has the Ultimax 15" driver and cabinet bundles for $300 each. Assemble a pair of those and power them with a pro amp like a Behringer iNuke NU3000DSP ($280), and you'll have two amazing 15" sealed subs plus access to sophisticated parametric EQ, volume limiting, and crossover controls—all for under a grand.

- Above $1000, the field starts to split between luxury and capability. On the one hand, you start to see unbelievably powerful subwoofers with huge drivers, such as Seaton Sound's amazing SubMersive line and JTR Audio's Orbit Shifter ($3500 factory direct). On the flipside, you see refined luxury subs like KEF's R400b ($1700), a model that packs dual 9-inch aluminum drivers inside a stylish 14" cube, and yet it manages to dig down to 16 Hz. If price is no object, Paradigm offers the Signature Sub 2 ($9000), and if that's still not enough, JL Audio's Gotham G213 V2 sub ($15,000) is worth a listen—it's as over-the-top as luxury subwoofers get.

Subwoofers are a passion of mine, and if you are reading this it's likely they are a passion of yours as well. The topic is too complex to summarize in one listicle, which is why it's great to have the AVS Forum community as a resource. If you are so inclined, leave a comment sharing your most important considerations when shopping for a subwoofer and what models you recommend at different price points.