How to Add a Subwoofer to Your Car Audio System-Step Two

Hopefully by now you have taken the time to evaluate your current car sound system and have decided upon a type of subwoofer to install.  If you have your stock system and are going to employ a basic amplified sub, you can start shopping right away.

The enclosed amplified subs are fast and easy to install.  You only need a good direct power connection and the ability to tap into your existing car speaker wires in most cases.  Simply follow the included instructions and depending upon the style you select, mount or hide in an appropriate spot.  Some of the smaller units are very flat and made to fit under your seat or snugly behind the seat in trucks and sports cars.  While the larger Bazooka tubes or Infinity Basslink style will require a bolt-down install to prohibit vibration and so they can provide maximum bass.

Now if you are upgrading your entire sound system as many do, you should have taken the time to consider any of the many complete packages offered by Kicker, Rockford Fosgate and MTX.  This should be your first step in deciding whether you want to go the route of buying all components.  If this is your choice, again determine the space needed and then its just a matter of selection of size and power.  The install of these packages can be as challenging as installing the separate components.  Remember you'll need a good ground for your amp, a direct power connection to your battery and appropriate rca connections to your source unit.  I'd suggest getting a quality amplifier installation kit which will make your life much easier.  The amplifier and kit will come with full instructions for installation of the amp.  Then its a simple connection of the amp to your box which is already wired to complete the job.

If you have decided upon buying separate components and a specific type and size of subwoofer enclosure, your shopping task has just begun.  The job of selecting the proper subwoofer really does take more effort than most people appreciate.  When shopping for a sub, don't think that bigger is better.  Through the years its been proven time and again that a small sub properly matched to an amplifier and sub box will out perform a mismatched 1000 watt monster sub.  Selecting the proper subwoofer for your install requires you to determine your exterior box size first as this is something that cannot change.  One you have that, the next steps involves selecting the power of your sub, amplifier size and the specific box.  Since the selection of the box will eliminate more subs then anything else, that is where you should start.

I would suggest selecting a few boxes from different manufacturers if necessary providing slightly different specs.  Pay particular attention to the sub box mounting cut-out size first.  Then check the maximum depth allowed.  This will narrow down the physical size of the sub you are able to install in any specific box.  The next step is to check the box specs very carefully for air volume.  You'll find most subwoofers will provide you with specifics for a sealed enclosure and vented enclosure.  As mentioned in the earlier article, the vented or ported enclosures will always be larger since they provide more air space for the car subwoofer.

There might be one short cut for you here depending upon your box choices.  Due to their unique characteristics, you'll find most shallow mount subs and square subs such as MTX or Kicker Solobarics match up very nicely with their specific types of boxes.  But due to the huge number of standard round subs, the possible volumes can vary greatly.  So take your time and begin your research.  Remember while in most cases matching a box air space exactly to any sub might not be possible, if the air space is too large or too small the sub simply will not perform properly.  So come as close as possible to the factory recommendations.

The next step is to check the depth of the box to ensure you can mount your sub properly.  There are spacer rings on the market if you need to add a small amount of clearance.  This sometimes becomes an issue with the heavy cast formed subs.  Beyond the depth, the cutout hole is most important.  Most manufacturers cut out the boxes to certain standard sizes.  If your box is MDF, you'll always be able to enlarge a hole with a jig saw.  At least one manufacturer used to provide install rings to shrink the diameter but most do not.  Besides you want a good air tight seal for the subwoofer ring so this is important.

So at this point, you have a box and subwoofer selected.  Now its time to turn on the power.  You should always shop for a sub by looking at its RMS or continuous power rating.  A few years ago all the manufacturers starting advertising peak power and this is only a marketing ploy to lure the buyer into thinking he is buying something much more powerful then it really is.  So for example, if you have a sub with a dual 4 ohm voice coil rated at 600 watts RMS, you'll need a mono or class D amplifier capable of providing 450 to 525 watts RMS at 2 ohms.  We always recommended staying at 75% to 80% of RMS to provide great performance while protecting you from blowing the sub.  But this is a matter of personal opinion and subject to debate.

Without going into a long discussion, you'll find subwoofers readily available in configurations of 2 ohms, 4 ohms, 8 ohms and dual 2, 4, and 6 ohms.  You need to match your combination of voice coils and ohm load to the amplifier.  This equation changes depending upon how many subwoofers you plan to install.  To help you out, see our info on how to wire subwoofers.

With this information in hand, you now can select a power amplifier capable of driving your subwoofer setup.  While you are probably familiar with many amplifier brands, for argument sake, we could rank Boss, Pyle, Pioneer, Clarion, Alpine and Kenwood in the most affordable category.  If you are looking for serious power though, I'd suggest considering JL Audio, Hifonics, Kicker or Rockford Fosgate.  This is especially true if you need more powerful class D amps.

So once you have your selection of sub box, subwoofer and amplifier in hand, you'll only need an amplifier installation kit and appropriate RCA connections for your source unit.  Finally the easy part which is the install itself.  Installation is nothing compared to making all these decisions.