Choosing The Perfect 12-Inch Sub For Your Boat

A subwoofer is a great addition to your boat's stereo system. Subwoofers are designed to reproduce lower octaves that traditional speakers cannot handle, enhancing the overall sound quality.

When it comes to choosing a subwoofer for your boat, you may consider factors such as size, mounting options, and marinization. Size is important as it determines the amount of space the subwoofer will occupy on your boat. Mounting options include free-air/infinite baffle, sealed enclosure, or ported enclosure. Free-air/infinite baffle subwoofers are ideal for boats with limited space, while sealed and ported enclosures offer better sound quality. Marinization ensures the subwoofer can withstand the elements, including water resistance, salt, UV rays, and fog.

Some popular options for boat subwoofers include the JL Audio M7 Series, Wet Sounds REVO Series, Rockford Fosgate M2 Series, and Polk Audio DB+ Series. When installing a subwoofer, it is crucial to ensure proper mounting and wiring to avoid any damage to your boat's electrical system.

Additionally, you may want to consider the number of subwoofers you need. A single subwoofer may not provide consistent bass output throughout the vessel, especially in open-air environments. Multiple subwoofers placed in different locations can help achieve optimum bass and ensure a consistent sound experience for all passengers.

Subwoofer mounting

When mounting a subwoofer on your boat, there are a few things to consider. Firstly, it depends on your boat's layout and design, but subwoofers are mostly installed underneath the helm. You can mount your subwoofer with a baffle or in a box, but this may depend on the boat's dimensions. If you opt for a box, you will need to screw it onto the boat, whereas if you use a baffle, you may need to cut new holes using a drill or use existing holes if they fit your subwoofer size.

It is also important to ensure that the subwoofer is mounted in a place that shields it from water and too much sun exposure. Additionally, you should only use marine-grade wiring for your boat's subwoofer installation, as this type of wiring is designed to resist damage from water, salt, and UV exposure.

If you are unsure about the installation process, it is recommended to seek professional help to ensure optimal performance of your audio system.

Subwoofer wiring

Wiring a subwoofer can be a complex task, and it's important to understand the basics before you begin.

Subwoofer and Amplifier Terms

First, let's explain some important terms:

• Single Voice Coil (SVC) subwoofer: A single voice coil sub with two wiring terminal posts, one marked positive and the other negative.
• Dual Voice Coil (DVC) subwoofer: A dual voice coil sub with four wiring terminal posts, two positive terminals, and two negative terminals. This gives you more options for wiring the sub in different situations.
• Impedance: The impedance load, or resistance against the amplifier's output signal, of a subwoofer coil. Subwoofer voice coils usually come in 2-ohm, 4-ohm, or 8-ohm impedances.
• Series wiring and parallel wiring: These terms refer to two ways of routing the speaker wires to properly manage the overall impedance load.

Wiring Diagrams

Now, let's get into the wiring diagrams. The diagrams below show wiring configurations for amplifiers and subwoofers that have already been matched for power capabilities. It's important to never connect subs to an amp that could give them more power than their total watts RMS power ratings, as this could damage the subs or the amp.

Mono 1-Channel Amplifier

• 1 SVC 2-ohm sub, mono amp: 2 ohms
• 1 SVC 4-ohm sub, mono amp: 4 ohms
• 1 SVC 8-ohm sub, mono amp: 8 ohms
• 1 DVC 2-ohm sub, mono amp: 4 ohms
• 1 DVC 2-ohm sub, mono low-imp amp: 1 ohm
• 1 DVC 4-ohm sub, mono amp: 2 ohms
• 2 SVC 2-ohm subs, mono amp: 4 ohms
• 2 SVC 2-ohm subs, mono low-imp amp: 1 ohm
• 2 SVC 4-ohm subs, mono amp: 2 ohms
• 2 SVC 8-ohm subs, mono amp: 4 ohms
• 2 DVC 2-ohm subs, mono amp: 2 ohms
• 2 DVC 4-ohm subs, mono amp: 4 ohms
• 2 DVC 4-ohm subs, mono low-imp amp: 1 ohm
• 3 SVC 2-ohm subs, mono amp: 6 ohms
• 3 SVC 4-ohm subs, mono low-imp amp: 1.3 ohms
• 3 SVC 8-ohm subs, mono amp: 2.7 ohms
• 3 DVC 2-ohm subs, mono amp: 3 ohms
• 3 DVC 2-ohm subs, mono low-imp amp: 1.3 ohms
• 3 DVC 4-ohm subs, mono amp: 2.7 ohms
• 4 SVC 2-ohm subs, mono amp: 2 ohms
• 4 SVC 4-ohm subs, mono amp: 4 ohms
• 4 SVC 4-ohm subs, mono low-imp amp: 1 ohm
• 4 SVC 8-ohm subs, mono amp: 2 ohms
• 4 DVC 2-ohm subs, mono amp: 4 ohms
• 4 DVC 2-ohm subs, mono low-imp amp: 1 ohm
• 4 DVC 4-ohm subs, mono amp: 2 ohms
• 1 SVC 2-ohm sub, 2ch low-imp amp: 2 ohms
• 1 SVC 4-ohm sub, 2ch amp: 4 ohms
• 1 SVC 8-ohm sub, 2ch amp: 8 ohms
• 1 DVC 2-ohm sub, 2ch amp: 4 ohms
• 1 DVC 4-ohm sub, 2ch amp: 8 ohms
• 1 DVC 4-ohm sub, 2ch low-imp amp: 2 ohms
• 2 SVC 2-ohm subs, 2ch amp: 2 x 2 ohms
• 2 SVC 4-ohm subs, 2ch amp: 2 x 4 ohms

Subwoofer power

When it comes to subwoofer power, there are a few key specifications to consider. Firstly, it is important to understand the difference between peak power and RMS power. Peak power refers to the maximum power that a subwoofer can handle for a short duration, while RMS (root mean square) power is the sustained power that the subwoofer can handle without overheating or distorting. It is generally recommended to match the RMS power of the subwoofer to the output of the amplifier for optimal performance.

Another important specification is impedance, measured in ohms. Lower impedance subwoofers can handle more power from the amplifier. For example, a 2-ohm subwoofer can handle twice as much power as a 4-ohm subwoofer. This is an important consideration when selecting a subwoofer, as it will impact the overall performance and loudness of the system.

In addition to power handling capabilities, the sensitivity of a subwoofer also plays a role in its performance. Sensitivity measures how efficiently a subwoofer converts electrical power into acoustic output. A higher sensitivity rating means the subwoofer will play louder with the same amount of power. Therefore, when selecting a subwoofer, it is important to consider both power handling and sensitivity to achieve the desired output.

When installing a subwoofer on a boat, it is essential to use a marine-grade subwoofer that is designed to withstand the harsh marine environment, including water, salt, and UV rays. Properly matching the subwoofer to the amplifier and ensuring that the subwoofer is mounted securely are also critical steps to ensure optimal performance and longevity.

Subwoofer placement

• Space Constraints: Be mindful of the available space on your boat. A 12-inch subwoofer will require adequate space for installation and proper ventilation. Consider the dimensions of the subwoofer and ensure it can fit comfortably without obstructing other essential components or storage areas.
• Acoustic Performance: The placement of the subwoofer can impact the overall sound quality. Aim for locations that provide optimal acoustics, reducing sound reflections and enhancing bass response. Consider the layout of your boat and identify areas where the subwoofer can deliver sound effectively without being obstructed.
• Ventilation and Moisture Control: Given the marine environment, it's crucial to address ventilation and moisture control. Ensure that the subwoofer is placed in an area with sufficient airflow to prevent overheating. Additionally, consider using waterproof or water-resistant materials to protect the subwoofer from moisture damage.
• Accessibility: Place the subwoofer in an area that is easily accessible for maintenance, repairs, or upgrades. This will simplify the process of connecting additional equipment or making adjustments to the audio system.
• Safety: Prioritize the safety of both the subwoofer and the passengers. Avoid placing the subwoofer in areas where it could be accidentally kicked or damaged by equipment. Also, ensure that the subwoofer's installation complies with safety regulations and does not obstruct emergency exits or critical boat operations.
• Aesthetics: While sound quality is the priority, consider the visual impact of the subwoofer's placement. Aim for a setup that blends seamlessly with the boat's interior design, enhancing the overall aesthetics of the space.
• Under Rear Seats: You can utilize the space under the rear seats to install the subwoofer. This provides a discreet location without taking up valuable storage space. Ensure that the subwoofer has adequate ventilation and doesn't interfere with the seat functionality.
• Side Walls: Depending on the layout of your boat, you can explore installing the subwoofer in the side walls, particularly near the captain's seat. This can provide a secure and out-of-the-way location while maintaining sound quality.
• Front Seats: If your boat has hollow front seats with locking waterproof latches, you can consider installing the subwoofers in these compartments. However, keep in mind that power handling may be affected, and proper ventilation is crucial to prevent moisture buildup.
• Custom Enclosures: You can design and build custom enclosures for the subwoofers, taking into account the specific dimensions and layout of your boat. These enclosures can be placed in various locations, such as under seats, in storage compartments, or in dedicated audio equipment areas.

Subwoofer sealing

Sealing your subwoofer box is important because sealed box enclosures reproduce low frequencies more accurately. The air inside the box acts as a shock absorber, allowing the subwoofer to move back and forth with more control. Here are some steps to help you seal your subwoofer box:

Make Sure the Cuts are Precise:

The sealant you use is important, but so is the precision of your cuts. Leaving air gaps or jagged edges will compromise your ability to properly seal your subwoofer box. Precise, clean, and straight cuts may even allow you to get away with not using any sealant, relying only on some glue and a few well-placed screws.

Get a Good Subwoofer Sealant:

There are many sealants you can use, with silicone being a common choice due to its availability. However, silicone does not expand like polyurethane-based construction adhesives, so it may not be ideal if your woodcuts are uneven and leave a lot of air space. Polyurethane-based adhesives, such as Gorilla Glue, expand as they cure, filling gaps and creating a strong bond. If you want to avoid silicone, you can also use acrylic latex caulking, liquid nails, or PL Premium Construction Adhesive.

Seal the Inside of the Box:

In addition to sealing the seams, you should also seal the inside surfaces of the box, especially if you're using porous wood like MDF. You can use a water-based adhesive caulk or add weight to the enclosure by using Boro-Silicate paste or fiberglass resin.

Seal All Extra Holes:

Use gaskets to seal any small gaps around the speakers and speaker terminals. Gasket is a rubber or plastic ring that goes around the hole to prevent air escape.

Ensure All Gaps are Filled:

Use epoxy putty to fill any remaining gaps or old holes. Redrill and use new screws if necessary to achieve a tighter seal.

Clamp and Let the Sealant Cure:

Different sealants have different curing times. For example, silicone typically requires 24 hours, but some people let it sit for several days. Remember that some sealants, like silicone, can damage the driver if not fully cured, so be sure to follow the curing directions.

Sand Away Excess Sealant and Add an Aesthetic Finish:

You can use wood filler, wood putty, or Bondo to give your subwoofer a smoother and more pleasing finish. Just be sure to work quickly with Bondo, as it dries fast. After applying the filler, sand it down and add your desired finish, such as varnish, paint, carpet, or vinyl.

Screw Down the Box:

To make your subwoofer box truly airtight, use mechanical fasteners like screws, nails, or staples. Remember to pre-drill and countersink the holes, especially if you're using plywood, to avoid damaging the wood. If aesthetics are a priority, you may want to avoid screws, as they can be difficult to cover up.

There are also some alternative DIY sealants you can use instead of silicone, such as regular tile grout or a strong, flexible adhesive like "Goope."

Frequently asked questions