How To Make A Sealed Box Louder

Norvan Martin
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Speaker and subwoofer boxes may be designed as sealed or ported. Sealed speaker boxes are punchier and produce more accurate sounds. Sealed subwoofers are often more accurate in frequency response and render instrumentals more convincingly.

Sealed enclosures enhance the listening experience but they aren’t typically as loud as ported enclosures. However, there are many tricks you can use to make them louder. In this article, we will look at how you can make your sealed speaker or subwoofer box sound louder and better. 

How To Make Your Sealed Speaker Box Sound Louder?

A sealed box is a form of enclosure that your subwoofer uses to get the most accurate and perfect bass audio output.

How To Make Your Sealed Speaker Box Sound Louder

You can do the following to make it louder and should better:

Seal Any Leak In The Box

Air leaks are famous for diminishing sound pressure levels.  The airtight seal created by sealing the inside of the box will prevent your subwoofer from sounding terrible at high volumes.

The best method is to use wood glue on the insides. If your box has a plastic terminal cup for connecting speaker wires to the box and the amp, glue it inside the box. 

Fill With Polyfill

Polyfill is the white material found in pillows and bed covers. It’s utilized in subwoofer boxes to trick the speaker into thinking it’s in a much bigger box. As a result, the bass is thicker and better. 

Tighten The Box

The subwoofer, as well as the terminal cup, is secured in the box with screws. To achieve a maximum seal, make sure each screw is thoroughly tightened using a hand drill or screwdriver.

Get A Durable Speaker Box

Purchasing a solid speaker box, whether you are a certified music enthusiast or not, is important in protecting your pro-audio equipment.

Aside from providing excellent sound quality, a good speaker enclosure may provide you with the reassurance that your speakers will not wander no matter how rocky the road gets.

The wood material used to make your speaker box will determine how good it will sound. Some recommended materials are Medium-Density Fiberboard and Baltic Birch Plywood.

Use A Thicker Speaker Wire

Many speaker owners tend to use electrical extension cords as speaker wires for their sub and speaker boxes. while this is an okay and cheap budget system, it doesn’t work as much when you are sending a 1000-watt RMS through it.

They contain copper wire strands that cannot take the current and this doesn’t help for the best audio quality. 

To be on the safer side, use a 12 gauge oxygen-free copper speaker wire.

How to Make Your Sealed Subwoofer Box Sound Louder?

There are several ways to make a subwoofer box sound better. The factor that takes the most precedence is the structural design.

How to Make Your Sealed Subwoofer Box Sound Louder

Sound experts have come up with tested ways to make your subwoofer box sound louder, they are outlined below;

Get A New Subwoofer Box Or Tighten Your Current One

Sounds weird right? The key to how to make a subwoofer box louder lies in the type of box you have. If you realize you have the wrong type of subwoofer box for your musical preference, then you can always look to replace it.

If you don’t have the budget for a new subwoofer box, try tightening the current one. Get new screws, use a new coating of glue or whatever else to tighten it. To learn more, check out our article on how to seal a subwoofer box

Stuff Your Sealed Box With Poly-fill

One of the best ways to improve the sound of your subwoofer box sound is to fill it with Poly-fill.

Essentially, by adding poly-fill, the air inside the box slows down, providing you with a deeper and richer bass sound. To learn more, check out our article on how much polyfill you need for a sealed subwoofer

Purchase A Stronger Subwoofer Box

Although this works for both Ported and Sealed boxes, the effect is more significant in sealed ones.

Sealed enclosures force compressed air to move around the box, this makes the wood fibers expand, making it inefficient in the long run.

Since sealed boxes are simpler and easier to make, you can get a custom subwoofer box made with a stronger material than wood.

How To Make Your Sealed Subwoofer Box Sound Better?

Optimizing your subwoofer box is essential, it is an important part of your listening experience. However, it is just that, a box.

A subwoofer box is merely a case built to house your subwoofer indefinitely. Therefore, now that you have the right subwoofer box and it is louder, how do you make your subwoofer box sound better?

Choose the Right Size of Subwoofer Box

When it comes to subwoofers, a larger box doesn’t necessarily translate to a better sound. A subwoofer box that is the wrong size for your subwoofer will create lower bass feedback.

Therefore, if you have a larger box than the optimal size for your subwoofer, it will not sound good. In fact, it has been known to damage subwoofers over time.

Proper Placement

Your subwoofer box will sound better in certain listening positions than others, especially when setting up the subwoofer in a room.

Make sure your subwoofer box is several inches away from a wall and not in a corner. While doing so, play some music that has heavy bass to allow you to assess the bass response in detail.

Extend the Heat Sink

Heat is the natural enemy of your subwoofer system. You can get the best performance out of your subwoofer by extending the heat sink on your amplifier.

This is especially important if you’ll be using the subwoofer heavily and for a prolonged period.

Check the free space in your subwoofer box to see whether it’s possible to add a larger heat sink. This will increase the surface area of the heat sink, dissipating more heat and allowing the amplifier to remain cool.

Proper Subwoofer Tuning

This is a free yet tedious way of improving the sound that your box produces. In concept, you have to tune your subwoofer to the perfect setting for your subwoofer box.

Since all subwoofer boxes are built differently, the same setting may not apply to all subsystems. To learn more, check out our article on the best subwoofer box design for deep bass.

You have to calculate the right frequency to use in your box, which might be overwhelming for a lot of people. It’s more of finding the right settings that suit the bass and the sound that we want in our subs.

Ported/Vented Subwoofer Enclosures

Vented enclosures, which, when accurately built and tuned to the correct frequency for the subwoofer, are generally louder than a sealed enclosure. Besides, they allow subs to reproduce the lower frequencies that are commonly found in Rap and Hip Hop music much better.


When trying to get the best performance out of your subwoofer, what matters most is how the subwoofer will sound best to your ears. Ensure the bass sounds properly integrated with other frequencies, get a properly designed subwoofer box, get an amplifier and you are good to go.

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Norvan Martin is the founder of 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