What is an SPL Subwoofer and Why Does it Matter?

Norvan Martin
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What if you wanted the deepest, roaring, and earth-shattering bass from your audio system even if you give up some sound quality?

Well, that is what an SPL subwoofer is for.

SPL or Sound Pressure Level subwoofers are designed to produce a tremendous amount of bass. They do this by moving a lot of air which generates a lot of sound pressure. However, this is at the expense of sound quality. The sound quality will be depleted, ill-defined, and possibly ear-damaging. 

Modern SPL subwoofers produce high acoustic pressure, which is what you require to create deep, roaring bass.

spl subwoofer

Today, we explain more about these specialized SPL woofers, how they work, and much more to help you get the best experience from them.

What is an SPL Subwoofer?

‘SPL’ is an abbreviation for Sound Pressure Level, and it indicates here that SPL subwoofers are highly effective at producing loud bass. All loudspeakers produce a certain degree of acoustic pressure.

Who Are SQL Subwoofers For?

SPL subwoofers are designed for individuals who are keen on habitually listening to music or watching videos with lots of deep, thumping bass.klipsch spl subwoofers

SPL subwoofers are also an excellent option for individuals who want to have the ability to measure the performance of their speakers accurately. You can measure sound pressure levels in decibels (dB).

Some people opt for SQ subwoofers in an attempt to get perfect quality sound. SQ stands for Sound Quality. Many people, especially those who are not keen on getting loud bass, say it offers impressive quality. We explain more about SQ vs SPL subwoofers below.

Nonetheless, their efficiency depends on the listener to an extent including your ears’ perception, distance from the subwoofer driver, and so on.

In other words, you have no objective way of determining the SQ subwoofer’s efficiency. So, you make the choice depending on your tastes and preferences. 

That is not the case with SPL subwoofers, as we shall see in detail below.

Do SPL Subs Sound Good?

In the low frequencies, SPL subs are arguably more efficient than a lighter-coned “SQ” sub. Shorting rings, less Le, and other measures are used in SQ subs to help reduce distortion. An SPL subwoofer can sound fantastic, however, the sound quality is ultimately determined by the enclosure rather than the subwoofer. And so if the enclosure is poorly fitted, the quality of sound released from the sub will be affected.

How to Measure SPL Subwoofer Efficiency

You can accurately measure the efficiency of your SPL subwoofer by following these steps:

  1. Collect the Required Materials
    • Sound Pressure Level Meter: Most of these are handheld devices, mobile, and lightweight. Moreover, they are manufactured following the IEC 61672 and other relevant international standards. You can use Class 1 or Class 2 meters. However, the first option provides more accurate results.
    • Microphone: You can use any wireless or wired mic.
  2. Power on Your Sound System: Of course, sound should be passing through the microphone when measuring SPL.
  3. Bring your Sound Pressure Level Meter near the SPL subwoofer: The meter will assess the sound that enters through the microphone and convert it to values and readings that are easily understandable. 
  4. Read the SPL of the Sub on the Meter: The sound pressure levels that the SPL subwoofer meter typically displays range from 20 dB to 140 dB. Nonetheless, you can set it to measure lower or higher levels of sound pressure than this.

Can I get more than this? Yes, you can. If you choose, you can set your SPL subwoofer meter to measure SPL over a long period or at specific intervals.

You can find the meter useful when assessing the impact of the sound that the sub produces on the environment.

SPL Subwoofer Efficiency

You can also store the data in the internal memory and download the info later for detailed analysis. This way, you get objective information that you can study to identify the appropriate control measures.

As we mentioned initially, this is a privilege that other subwoofers lack despite that they also produce some acoustic pressure. You might use an SPL meter to measure their sound pressure level, but that may not translate to improving the subwoofer’s sound clarity and fidelity.

Which are the Best SPL Subwoofers?

Since SPL subwoofers are designed to help you get deep bass, some subs are not favorable for SPL setups. The best option here is a ported enclosure.

The typical primary features of ported enclosures are:

  • Low distortion around port tuning
  • Require little amp power
  • Louder bass and more “boomy.”
  • Large box
  • Less accurate bass
  • Port

Please note that the efficiency of ported enclosures results from their ability to drive a lot of air and create tremendously intense acoustic pressure. By enabling air to flow freely through the port, SPL subwoofers can roar more.

Another alternative enclosure for an SPL subwoofer is the sealed box. We do not recommend it as it can’t create and sustain high sound pressure levels for an extended period.

However, it can work for someone who prefers ‘tight’ and focused bass. However, if you are for booming bass and maximum volume, the ported option suits your needs. Here are the key features of sealed enclosures that influence the subwoofer’s bass:

  • Small box size
  • Requires lots of power for louder bass
  • Tighter and focused bass

In short, since a sealed box moderates the movement of the subwoofer’s diaphragm, the loudspeaker hardly thunders or roars. So, the choice is yours.

What Can Affect Your SPL Subwoofer’s Bass?

Size of Subwoofer

As we have seen, the type of your sub’s enclosure is essential, but you need to think seriously about the sub enclosure’s size. If you choose a small ported box, your SPL subwoofer will still likely perform below your expectations.

That explains why many SPL subs are very large. Many of them in the market today are 15 inches and 18 inches. Other users also have multiple SPL subwoofers.

With huge or multiple subwoofers, you get more cone area for creating more air pressure.

Type and Quality of Speakers and Tweeters

Your choice of speakers and tweeters plays a vital role in the efficiency of SPL subwoofers. Of course, you need high-quality speakers.

Other than that, your subwoofer will make sure your neighbors can hear you if you are using metal tweeters. They are great at preventing the bass from draining our high audio frequencies.

Remember, deep bass can quickly destroy a weak tweeter cone or diaphragm.

Impedance Matching

Don’t forget that proper circuit operation relies heavily on the circuit’s ability to transfer signals efficiently.

So, if you choose the right SPL sub but fail to treat impedance correctly, it is highly likely that you will experience interruptions like reflections of signals and standing waves. Some users often incorrectly blame this on SPL subwoofers.   

To avoid problems, you should ensure that your subwoofer’s impedance falls within that of your amplifier.

Best Music Genres For SQL Subwoofers

The best music genres for SQL subwoofers are those that are bass-heavy including rap, hip-hop, punk, techno, or other synthesized bass music.

SPL vs SQ Subwoofers

In addition to SQL subwoofers, there is another type of subwoofer on the market referred to as SQ or sound quality subwoofers. 

As you may have guessed, SQ or sound quality subwoofers are designed to accurately reproduce the original source sound with the best sound quality. However, they won’t deliver the thundering bass that you can achieve from SPL subwoofers.

You can read more in our article on SQL vs SQ subwoofers.

What’s Better In An SPL Subwoofer a 12 or a 15?

The subject of whether 15-inch subwoofers have a better foundation than 12-inch subwoofers is difficult to answer because, to be honest, “better” is a subjective term. Because 15-inch subwoofers are bigger, and so can displace more air than 12-inch subwoofers, the smaller ones will sound crisper and sharper.

This makes the 12-inch subs greater for quality bass generation and able to produce amazing sound on multiple frequencies.

SPL 12 Subwoofer Box

The SPL 12-inch shared vented dual enclosure comes with a dual shared chamber. This is a heavy-duty subwoofer box made with a ¾ inch MDF with 1 inch face.

It has gold gold-tipped spring-loaded terminal and a premium charcoal-colored carpet finish.

Key specifications include:

  • 6 cubic feet of air space per sub
  • Height: 13.25 inches
  • Width: 36 inches
  • Depth: 16.25 inches
  • The tuning frequency of the sub-box is 39Hz

SPL 15 Subwoofer Box

Also referred to as shock 15’x2’ final, this SPL subwoofer box carries two subwoofers and is 15 inches in length.

Key specifications include:

  • The material thickness is 0.6 inches
  • Net internal volume is 6.28 cubic ft
  • The tuning frequency of the box is 34 Hz
  • The port area is 28.3 square inches
  • The pipe’s inner diameter is 6.00 inches
  • The pipe’s length is 4.61 inches s

SPL 18 Subwoofer Box

Type Subwoofer loudspeaker
Color Black
Frequency response 33Hz – 380Hz
LF driver 18 inch x 1
Power rating 900W
Peak power 3600W
Impedance 8 ohms
Sensitivity 100dB
Cabinet construction 18mm plywood
Cabinet finish Polyurethane coating
Dimension L715 x H525 x W762
Material thickness 0.71 inches
Net internal volume 7.06 ft3
Pipe inner diameter 9.84 inches
Pipe length 22.56 inches
Weight 46Kg


SPL Vs SQ Subwoofers

SQ Subwoofers

An SQ subwoofer is built for sound quality. They are typically smaller in size and deliver less power compared to SPL subwoofers.

This does not however mean that they are lame in terms of power output. Although they may not be louder than SPL, they can still produce clean and clear bass sounds.

SQ subwoofers perfectly support music genres that rely on a precise bass foundation such as hip-hop, EDM, and R&B. Also, the subs perform best with rap or electronic dance music. If you are not up to music with powerful bass, an SQ subwoofer is the best.

SPL Subwoofers

SPL subwoofers are subwoofers that are built for power and volume. They are larger in size and have more power than SQ subwoofers.

If you prefer to listen to music with some ground-breaking bass, then n SPL subwoofer is the way to go. They can be very loud and are a perfect choice for people who love music with a powerful bass foundation such as rock and metal.  

Check out our guide on SPL vs SQ subwoofers to learn more.

SPL Gorilla Subwoofers

There are several SPL Gorilla subwoofers in the market today. However, it is important to consider the peak power when choosing the best for your home theater. Here are some of the SPL Gorilla subwoofers to buy:

  • Loud Sound SPL Audio Subwoofer Die Casted Aluminum Frame ODM OEM Service
  • Audio System SPL Car Speaker, Pro Audio Car Subwoofer Black Anodized Finish
  • 12 Inch SPL Car Speaker 1 Layer Magnet With Heavy Gauge Steel Basket
  • SPL Car Speaker Triple Stacked 450oz High Energy Magnets 2 Gasket Layers


SPL subwoofers are perfect for those who want to fill their rooms with deep bass. However, you should opt for a sizeable ported enclosure, metal tweeters, and quality speakers to get the best overall quality. Given the high demand for current, you should also correctly match the impedance of the SPL subwoofer and amplifier.

That’s all. We hope you will put these tips into practice to be able to get your desired high-pitched sound.  

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Norvan Martin is the founder of BoomSpeaker.com. He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin