Article by Capt. Steve Katz
How low can you go?
While it may not surprise you, some people like to listen to music on their fishing boats. Whether at the dock, underway or while fishing, music seems to mix well with the enjoyment of boating and fishing.
Besides the elements, the marine environment is more difficult to match a sound system to your needs than for a car or home. On a boat, you have many physical restrictions and a wide variety of ever-changing outside influences that affect your stereo system. The number one obstacle in designing a sound system is the speakers- type, size and location. This can be difficult on a boat, along with running the wires to the speakers. Once the speakers have been decided upon, they need to receive enough power to make them perform well. Usually, this means an external amplifier, more powerful than the one included inside of the main stereo unit. Finally, the music source needs to be selected. Today there are many choices, ranging from a full feature high-end stereo that integrates with other marine systems all the way to a simple system that works only with Bluetooth or an auxiliary input. All are good choices depending on the needs of the users.
While many off-the-shelf stereo systems do just fine for most boaters, there are always the people who want a little more out of their system and want to create a system similar to their high-end home or vehicle systems. One of the most popular additions to a good system is a subwoofer. Yes, that same giant speaker system in the neighboring car that vibrates your vehicle at a stoplight. Designing and installing the proper subwoofer system is not to add a loud thumping noise but to seamlessly add to the overall quality of your sound system.
What does a subwoofer do? The purpose of a subwoofer is to reproduce low pitch audio frequencies, known as bass or sub-bass in the 20–200 Hz frequency range, from a dedicated woofer speaker. A woofer is a speaker designed to produce the lower frequencies of sound. A tweeter is a speaker designed to reproduce the higher end of listen frequency. Most general purpose speakers are a combination of a larger woofer and smaller tweeter in one housing, providing a convenient and reasonably priced speaker system that produces good sound in the mid-and-high frequencies. The smaller diameter, usually 4 to 6-inches, and acoustical properties of a general purpose speaker don’t allow for the gut pounding lows that a subwoofer can reproduce
A subwoofer is a dedicated speaker system, designed only to reproduce these low frequencies and these speakers often need to be tuned electronically to filter out the higher frequencies that the speaker was not designed for.
Creating low frequency sound at reasonable volume level requires a lot of power, a large diameter woofer that can move a lot of air. Most subwoofer systems for home and mobile are pre-engineered within an enclosure that you mount where space permits and wired into your stereo system. Often on a boat we do not have the space available to install one of the pre-engineered systems and many boat owners end up installing a subwoofer speaker(s) wherever space permits. While this can work well, it is more difficult to select the proper speaker and mounting location to produce the expected improvement in low frequency sound. Luckily, the low frequency range is not as direction specific as the higher frequencies and location from the listener is not as critical as it is with a traditional, full range speaker. You know this when the base-thumping car pulls up next to you at the stoplight and your car vibrates, but you can’t hear much of the mid or high range from the other car.
Generally, a subwoofer is designed to work inside an enclosure at a given volume. This helps control the woofer from overextension that can cause distortion and damage to the speaker. Often times, a creative woofer installation can allow you to design the proper enclosure, such as the area under a bench seat or in a cabinet area, etc. If a predesigned or custom enclosure is not available, there are subwoofer speaker systems that are designed for an infinite baffle, not requiring a specific volume enclosure.
An infinite baffle woofer generally requires the subwoofer to be mounted on a sealed, rigid surface that prevents the rear exiting sounds waves from reaching the front of the speaker; otherwise the sound waves can cancel each other, reducing the effectiveness of the subwoofer speaker system. Subwoofer specifications usually indicate if they are designed for an infinite baffle or an enclosure. As an example, the popular JL Audio subwoofers in 8-inch and 10-inch diameters may all look the same, but JL Audio manufactures two distinct subwoofer speakers models, one for enclosures and one for infinite baffles.
If you have ever looked through the grill of a working speaker , you have noticed the large diameter woofer moving in and out with the music, turning electrical signals into sound waves. It takes a lot of power to move a large diameter speaker. Generally the more power the better, as long as it does not exceed the speakers rating . Therefore, it is common to see separate amplifier(s) dedicated to the subwoofer on a marine installation, usually 100 watts at a minimum and 600 watts for a high-end system. Comparatively, this same 600 watts can easily provide adequate power to 4 or 6 traditional marine speakers.
So if you want to pump up the bass on your sound system, select the appropriate subwoofer speaker system for your installation location, provide adequate power to the speaker system and tune the speaker levels to match your desired listening levels and the speaker’s ratings. Then all you need to do is sit back and enjoy!
Captain Steve Katz is the owner of Steve’s Marine Service and holds NMEA, AMEI and NMEA2000 certificates along with ABYC Master Technician certification and factory training from many manufacturers. To reach Steve, call (631) 264-1600.
