How to Select a Car Audio Subwoofer

Usually the very first upgrade anyone considers making to their OEM car sound system is to add a subwoofer.

It really isn’t surprising since OEM speakers are simply too small and not of sufficient quality to accurately produce low bass frequencies. Subwoofers provide the most immediate improvement one can make to a car audio sound system. Consequently one of the most frequently asked questions is: “How do I select a subwoofer?”

Actually, your selection will depend on several factors such as your personal preferences in music, your budget and available space in your. The amount of space you have to dedicate to your subwoofer’s enclosure should be the first thing you consider. In the majority of cases, this decision narrows the field very quickly. But what if space is no problem?

Subwoofers range in size from 6” to 18” in diameter. Most are round in shape but in recent years the new square shapes are becoming more and more popular. Materials used in the speaker cones can be made of treated paper, light metals such as aluminum and even various types of composites. Paper cone subwoofers tend to sound the most natural and true to life but paper is the least durable. Aluminum Cone woofers were one of the best materials to use for quick, tight bass response (sound quality applications-SQ) because they produced very low frequencies in small sealed boxes. There are some very good musical subwoofers today that offer excellent sound quality while also presenting exceptional SPL (Sound Pressure Level - An acoustic measurement of sound energy, typically expressed in dB-SPL). Normally, High SPL is associated with LOUD BASS. In most cases, High-End Subwoofers will tend to offer a good balance of both SPL and SQ. You’ll find composite woofer cones used today by some of the most respected names in subwoofers to create exceptional sound quality. At one time, a shopper had to decide which was more important to him, SPL (LOUDNESS) or SQ (musical sound quality), but there are currently many high quality subwoofers noted for both.

As mentioned, although woofers range from 6” to 18”, the size of the individual subwoofer isn’t always the most important thing to consider. The larger surface area of a specific subwoofer usually translates into deeper bass, but smaller subs might sound cleaner and actually might hit harder due to the fact that they have less mass and can respond more quickly. Most of the larger manufacturers have gotten away from even producing the 18” size and many are moving away from even the 15” size due to decreased popularity. Let’s be honest, smaller vehicles translate into smaller trunk space and this definitely has a bearing on how large an area the owner will sacrifice for his sound system. Today’s shopper is more educated and looking for good musical sound quality in most cases. This can easily be achieved in running 8”, 10” or 12” model subwoofers. Multiple subwoofers will actually play louder then a single larger sub in most cases and can handle more power. This isn’t rocket science but two 10” subs can move more air then one single 12” sub just due to the surface area of the subwoofer cones. You get the idea.

Another area to consider is whether you want to use a Dual voice coil (DVC) or a Single voice coil (SVC) model subwoofer. The primary advantage of the dual voice coil speaker is wiring flexibility. A single dual voice coil driver offers the user three hookup choices: parallel, series and independent. In a parallel hook-up the driver’s impedance will be half that of each individual coil. A series hook-up results in twice the impedance of each single coil. Finally, you can wire each voice coil to a separate channel of your amplifier, which can be useful if your amplifier is not mono-bridgeable or if you are bridging a four channel amplifier down to two channels to run your sub. Just for an example: to run two 4ohm DVC woofer- Wire the individual woofers in Parallel so they each will show a 2 ohm load. Then wire the two woofers in a Series and the amplifier will see a 4 ohm load. Almost any amplifier can be bridged mono at 4 ohms. At one time you would pay a premium price for a DVC model but today it seems prices are similar regardless of voice coil selection.

Finally, the shopper really has to go back to his available space and consider what type of music he listens to most often. This is relative since although one might want to run a 12” subwoofer, there can be a considerable amount of difference in the size of various types of boxes. It’s good to take this into consideration when making your initial subwoofer choice so you aren’t disappointed in the results. Different types of boxes are generally used for different types of music. Sealed boxes deliver tight, controlled bass with excellent Sound Quality and are best for jazz, classical, country or pop music. Ported enclosures are usually larger and tend to have a boomier, richer, more resonant sound which lends itself to hip hop and heavy metal music. Bandpass boxes are the largest and are known for an aggressive, boomy sound which is good for rap, reggae, and hard rock music. When selecting your subwoofer, be sure it can be used in the type box you are considering. Not all subs are recommended for vented or bandpass applications and very few are suitable for free air applications. Plan ahead and you will not be disappointed.

One other consideration is that of a custom stealth style subwoofer enclosure. These are made custom for your vehicle and always take up the least amount of space. They will cost a bit more but most consider the cost well worth the appearance. Normally, these boxes are designed for subwoofers designated for small sealed enclosures and produce relatively good SQ.

So after considering your choice of box type and the amount of space available you are armed with the basic information that will allow you to start looking for your new subwoofer. This article should help you narrow down your search for a new subwoofer. You will find a broad span in pricing and quality so happy shopping.