How to Waterproof Speaker and Subwoofer Box (6 Checklists!)

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Every professional in the audio industry will tell you that adequately sealing speaker and subwoofer cabinets to make them waterproof, is very important. This is because, most speakers are built to have paper diaphragms in their drivers, and other parts that are sensitive to humidity and moisture.

Therefore, waterproofing of speaker and subwoofer boxes helps to protect your speakers and subs from any harm that may be caused by water and humidity.

If you have ever got your speakers wet by mistake or damaged by rain, then you definitely know how important waterproofing can be to your speaker and subwoofer box.

This is why some speaker manufacturers use water-resistant materials like rubber in manufacturing certain parts like cones and surrounds. However, other internal speaker parts are not waterproof and can still get damaged easily when exposed to moisture.

Due to this, you need to take up the responsibility of ensuring that your speaker and subwoofer boxes are fully waterproof. Doing this is very necessary to protect your speakers and subs against moisture and water damage.

Therefore, are you on the lookout for the best way to waterproof and seal your speaker and subwoofer boxes? If so, then you need to read this article to the very end.

How to Waterproof and Seal Speaker or Subwoofer Boxes

Just as I mentioned in my previous article titled “Can Speakers Be Stored in a Garage?”, moisture and dampness that enters speaker enclosures, can cause severe damage.

Thankfully, there are several ways to ensure that your speaker and subwoofer boxes are sealed from water, moisture, and dampness. Some of these ways can be quite tedious and time-consuming.

However, after hours of research, I have come across one of the best yet simple ways of waterproofing your speaker and subwoofer boxes.

The great thing about this particular option is that the process of waterproofing your speakers and subwoofer boxes can be done without having to spend lots of money.

What most people do not know is that properly done waterproofing actually improves speaker performance as well. This is because, when a speaker enclosure is sealed properly, there will be no air leaks out of the speaker box. This will ultimately improve the speaker or subwoofer’s performance significantly.

Read along as we explore this simple yet cost-effective way to waterproof speakers and subwoofer enclosures. Doing this right will ensure that, you get the best sonic results out of them whiles protecting your gear from moisture.

Ensure That the Speaker Enclosures Are Well-Cut

The only way to ensure that a speaker or subwoofer box is entirely sealed or waterproofed is to make it as airtight as possible when building the speaker from scratch.

Therefore, this process of waterproofing your speakers and subwoofer boxes begins by ensuring that the speaker enclosures are well-cut from the onset. You should bear in mind that these panels for the speaker enclosure must be carefully cut and precisely aligned to make your work easy in the later stages.

This is because, if there are gaps in the panels, the cabinet enclosure will never be waterproof or airtight. Hence the need to carefully measure and cut the panels for the speaker enclosure.

Therefore, ensuring that every panel in the speaker box is precisely cut and aligned means that you are already moving in the right direction.

Ensure That the Speaker Enclosure Is Assembled Well

After the speaker or subwoofer box panels have been correctly aligned, the next thing to do is to carefully assemble the panels of the enclosure. In plain terms, every panel of the enclosure must be joined together well.

It is important to note that, there can be no air gaps, cracks, or spaces between any joints in the enclosure.

To help you achieve this, the joints and edges where each panel meets must be glued and screwed together as tightly as possible. Doing this will ensure that, all air gaps, cracks, or spaces between any joints in the enclosure are sealed off.  

Now that the speaker has been assembled as tightly as possible, let’s move on to the next steps involved in the whole process of waterproofing your speaker and subwoofer cabinet boxes.

Coat The Speaker Enclosure Inside and Out

When the speaker or subwoofer box has been put together and tightened down, the next step is to coat the wood used to make the enclosure. This coating must be done on the inside as well as on the outside of the enclosure.

This is important because the wood used in making speaker enclosures typically has tiny pore spaces in them. That is why high-pressure air can force its way through the wood.

What this means is, the wood itself may not be fully airtight or waterproof. Thus, even if there are no spaces between the edges and joints of the box, exposure to moisture can still make the porous wood swell.

Therefore, to make the speaker or subwoofer box truly waterproof and airtight, the wood must be coated with a liquid sealant that protects against moisture.

After coating the inside and outside of the enclosure with the liquid sealant, you should leave it to dry properly. When this substance dries, it will make the wood resilient to water and also prevent air from escaping from the speaker enclosure through the wood.

There are quite a number of liquid sealants that can be used to do this. However, these liquid sealants come highly recommended; Bondo Fiberglass resin (on Amazon) and Tekbond PVA Wood Glue (also on Amazon).

Depending on their availability, you can go for any of these adhesives. However, any other form of sealant is suitable, as it will flow into all of the cracks, gaps, and spaces in the wood as well as the joints.

Use A Rubber or Expanding Sealant for All Internal Seams

After the internal sealant on the wood has fully dried, the next step is to add some expanding sealant to the corners and joints of the inside of the speaker box.

The reason for this is that, when an expanding sealant cures or dries, it becomes rubber. Thus, it is able to withstand the vibrations within the speaker cabinet without separating or coming apart.

Therefore, doing this adds rigidity to the cabinet box. It makes the box more rigid by preventing the panels from coming apart. In addition to this, it further ensures that the speaker enclosure is sealed as tight as possible.

An expanding sealant such as Kraken Bond Caulk (on Amazon) is excellent for this. Alternatively, if you do not have access to an expanding sealant, an expanding glue, like Gorilla Glue (on Amazon) can serve as a great alternative. All these will do this job well,

Cover The Enclosure with Primer and Outdoor Paint

When the inside of the speaker or subwoofer enclosure has completely cured and is well-sealed, it is time to turn your full attention to the cabinet’s exterior. This process is a little more straightforward, as the exterior is more accessible.

You should coat it in outdoor sealant primer, and paint the cabinet with outdoor paint. For the best results, you should apply just a few coats of paint and let it fully dry between each layer.

It is always nice to have a good-looking set of speakers rather than having them look like they were cobbled together with scraps. Therefore, take your time to do this process well. Doing this will further seal the speaker box from air leaks and ensure that the cabinet is fully protected from external moisture and dampness.

In summary, the better you apply the paint and primer, the better the speaker enclosure will be sealed, and the better the cabinet will look.

Use A Gasket for The Speaker Cone

The final step in the waterproofing process is to use a well-fitting rubber gasket beneath the speaker mount. This gasket for speakers is a ring made of rubber or other sealant material that has been designed to seal a speaker to its enclosure by providing a smooth mounting surface.

Mounting the speaker inside the cabinet with a rubber gasket beneath it has a lot of advantages.

Doing this improves the speaker’s performance. It also mitigates excess vibrations and controls sonic leaks. Overall, mounting the speaker inside the cabinet with a rubber gasket beneath it helps to keep the speaker cabinet as airtight as possible.

Therefore, every speaker and subwoofer should be fitted with a gasket for the best results possible.


Waterproofing and sealing a speaker or subwoofer box is always a great thing to do. This process helps to protect your speaker and subwoofer by keeping them safe from humidity and water damage.

That notwithstanding, waterproofing also improves the performance of speakers and subwoofers by allowing the cabinet to function more effectively without losing air pressure. For the best possible sonic performance, you need to ensure that your speaker and subwoofer boxes are sealed correctly.

If you take the time to ensure that your speaker and subwoofer boxes are properly sealed, they will last far longer, perform much better, and will not be damaged by moisture and dampness.