Driving Your Subwoofer

Driving your subwoofer

You should also consider the type of amplifier with which you’ll be driving your sub system. Both under-driving a subwoofer (feeding it too little power) and over-driving a subwoofer (feeding it too much power) can cause it to dis¬tort and possibly fry. Make sure you match the power requirement spec of the subwoofer with the appropriate amount of amplifier power.

You may also be faced with the choice of whether to buy a sub box with a ohm, 3-ohm, 4-ohm, or 8-ohm subwoofer with either single or dual voice coils. I cover this in-depth later in this chapter, but suffice it to say that dual-voice-coil subs offer greater flexibility.

Brand and build

There are dozens of prefab sub boxes to choose from, of varying quality and finishes, but I recommend that you stick with a reputable manufacturer. That’s not to say that a sub box from a brand you’ve never heard of won’t perform well and last for years, but if you come across a sub box that’s super-cheap compared to other comparable models you’re considering, chances are there’s a good reason why — and it’s probably not because it’s an incredible bargain. Just remember the old adage that you get what you pay for.

At Beyond a recognizable brand name, you’ll want to pay attention to a prefab sub box’s build and construction. Although you won’t always be able to see [Z5* g inside a box, ask the salesperson at a store or the person you’re buying the box from how it was constructed. What are the materials (wood, plastic, or fiberglass) and how is it held together (screws, nails, glue, or some combination of these)? Medium-density fiberboard (MDF) is the material of choice in construction of many subwoofer enclosures, and the thickness of the wood is also important. Look for sub boxes that are built with wood that’s at least 5/8 of an inch thick. Ask to make sure that the interior of the box is braced or reinforced so that the walls don’t flex.

You should also want to check out the type and quality of the terminals, where wire from an amplifier connects to the box (and hence the subwoofer). Some prefab boxes offer simple spring-loaded terminals, which you push down on to insert a bare speaker wire from an amplifier, whereas others provide higher quality gold-plated binding posts.

The finish on the outside of the box doesn’t affect how it sounds, but it does affect how it looks in your vehicle’s interior. Most prefab boxes are finished in automotive carpet, but some have cosmetic flourishes of fiberglass, vinyl, and other materials. Some prefab boxes also feature a see-through Plexiglas panel that allows a look at the sub inside. Prefab boxes can come with or without grilles, so ask if a grille is included. In general, it’s always a good idea to have a grille to protect the subwoofer’s cone from damage. 

Pouter hitters

You can also get a prefab subwoofer box that comes with a built-in amplifier (as shown in Figure 16-2). Although these rarely sound as good as a custom sub box or even a good prefab box matched to a separate amplifier, they are a quick way to add bass to almost any ride.

Figure 16-2:

Infinity's BassLink T powered subwoofer box.

Courtesy of Infinity

The advantages of amplified sub boxes are

Cost: An all-in-one amplified subwoofer box is usually cheaper than buying a separate subwoofer box and an amplifier.

Convenience: Amplified sub boxes are usually plug-and-play devices, so you don’t have to hassle with installing an amplifier and then wiring it „ up the subwoofer. You typically just need to supply an amplified sub box with 12-volt power from the car’s electrical system and a signal from an audio system. Some amplified sub boxes even have high-level or amplified inputs that allow them to be added to any stock stereo system. Plus, amplified sub boxes can be easily removed and moved to another vehicle.

Size: Amplified sub boxes are typically compact and can fit easily into almost any car

Space-specific subs

One of the challenges of adding a subwoofer box to a space-stingy vehicle such as a compact, sports car, or pickup is finding space for it. That’s why companies started providing vehicle-specific sub boxes that fit snugly in a predetermined spot in a car interior. Some come with a subwoofer already loaded into the enclosure and some come without a sub. Whether it’s behind the seat of a pickup truck or in the trunk or hatch of a car, vehicle-specific subwoofer boxes are perfect for those who want bass without taking up too much space, as well as a low-key appearance (as shown in Figure 16-3).

Figure 16-3:

A JL Audio Stealthbox designed to fit in the hatch of a Chrysler PT Cruiser.

Courtesy of JL Audio