The Basics of Subwoofers

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Subwoofers, also known as Subs, are measured by the cone distance. There are several types of subs in the world, ranging from sizes 6" to 18" woofers. Where shall I begin? Subwoofers, also known as drivers, are very entertaining products, but require effort and pride to achieve a properly built system. A Sub is a loudspeaker that is intended to play bass frequencies between 150 hz down to 15 hz. The reason why subwoofers were built is because typical house speakers are not large enough to produce the air displacement it needs to play that low bass frequency. To find the appropriate speaker for you, you need ask yourself how much power are your planning on running? With enough experience, an individual can push a speaker to its mechanical limits by giving it more than rated power without blowing the sub. Blowing a sub is not a happy experience nor is it a good scene, so I will give you the basics of running a sound system with the correct subwoofers.

A driver has voice coil configurations that will let you wire it to the amp. Nowadays, subwoofers come in dual 2ohms or will come in dual 4ohms. There are many advanced subwoofers that have quad voice coils and there are older subwoofers that only have a single voice coil. The number of voice coils does not do anything except it gives the buyer several choices to wire. The more voice coils, the more the choices you have. As I said earlier, most subwoofers usually come in dual 2ohms or dual 4ohms configurations. Why do manufacturers make subwoofers with quad voice coils? These subs are typically for advanced competitors who use these coils to wire the amp at a very low ohm load, perhaps less than 1ohm. Warning: Wiring an amp less than the recommended ohm load may fry your amp. So which type of sub do I purchase?

The type of subwoofer really depends on the user. Like i said earlier, there are hundreds and hundreds of subs on the market. The first question you have to ask yourself is "how much power am I going to run?". Once you determine the amount of watts you intend on running, time to choose a subwoofer. There are two paths in choosing a sub. The first path is to purchase the amp, then choose the correct sub with the correct voice coil configurations. The other path is to purchase the sub first then, purchase the amp that matches to the correct ohm load. Ohm load is a very important theme that an individual needs to know because without knowing what ohm your amp is seeing, you can very likely fry the amp along with the sub. So what's an Ohm? We need to understand "Ohm's Law" in order to complete a successful build. There are two ways you can wire drivers, which are in series or parallel. Wiring in parallel, cuts the ohm load in half. Wiring in series will double the ohm load. How do you know which ohm load you need? This is a very good question you need to ask yourself. This all depends on the amp and how the lowest ohm load it can safely handle. Many Class D amplifiers will produce most of its power at 1ohm, which means the safest ohm load the amp will take is 1ohm.

Let us begin with a basic example for a single subwoofer. A subwoofer with dual 2ohm voice coils is wired in parallel to achieve what ohm load? If you do not know the answer, there are many woofer wiring wizards online that will direct you in the correct pathway. As I said earlier, wiring a subwoofer in parallel cuts the ohm load in half. If the driver is dual 2ohm and is wired in parallel, the resulting ohm load is 1 ohm. Introducing multiple drivers can be confusing; therefore, I suggest using one of the wiring wizards online as a helpful tool. Wiring two drivers in parallel cuts the ohm load in half twice. For instance, two drivers that have dual 4ohm configuration are wired in parallel. By wiring two subwoofers in parallel, you cut the ohm load in half, but since there are two drivers you cut the ohm load in half twice. This basically means one-fourth of the driver's configuration. You cut the ohm load in half,which results at 2, then cut that load in half. Cutting 2 in half gives, you a final ohm load of 1ohm. The other way to look at it---- one-fourth of 4 yields a result of 1ohm. If your wiring anymore than two drivers, I would highly suggest you clarify your result with someone else or use a woofer wiring wizard online.

A useful tool in determining how to wire your subwoofers can be located here

So which sub do you choose? You can look at the manufacturer and do some research on their car audio products. As mentioned in the amplifier section, there are several manufactureres that stand by their products, and there are even more manufacturers who produce very low quality products. Just because a manufacturer produces quality plasma and LCD screens does not indicate that their car audio products must be good. After finding out the basics, it's time to choose the right driver for your particular setup. Keep in mind that there are drivers that are specially engineered towards sound quality, while there are drivers that are geared strictly towards SPL, Sound Pressure Level (pure bass). Furthermore, there are few subs that will yield better results in a sealed enclosure vs. a ported enclosure. The majority of subwoofers generally increase in SPL levels with a properly built ported enclosure. How do you determine a well-built sub? For the most part, you can look specifications. If a driver does not tell you the specs for a recommended enclosure, I wouldn't go any further in choosing that sub. Also, if a subwoofer does not tell you it's RMS power handling, don't bother with that particular model. All subwoofers have a mechanical, thermal, and structural limit as to how much power it can take. With that said, there is no such woofer as a driver that takes unlimited power.