• Pimp your ride with thumping bass.model speed car image by timur1970 from Fotolia.com
  
  When it comes to music, who can resist a funky backbeat and pumping bass line? For modern music lovers, that's where the excitement is and it's what a subwoofer delivers. It's easy to get great bass in your living room but it takes more work in a vehicle. That's why some bass lovers build their own subwoofer boxes.
  
  

Choosing a Driver

• You can't build a perfect box without matching it to the driver you plan to put in it. One obvious reason is that the size of your speaker determines the size of your box but your driver's sound characteristics are also important. You can limit your driver search to speakers that are smaller than a box with those dimensions. Next, you'll need to match your driver's Fs (Free Air Resonance in Hz) to its Q Parameters (how well its suspension controls movement). Once you know the Fs, you can build an enclosure that won't ring at the speaker's resonant frequency. If you know the Q Parameters, you can match your enclosure design to the driver. The total Q (Qts) of these parameters is determined by multiplying the Qms (driver's mechanical control measurement) by the Qes (driver's electrical control measurement). According to The12Volt.com, if the Qts is .4 or below a vented enclosure typically works best; if it's less than .7 but more than .4, you're better off with a sealed box; and if the Qts is above .7, a free-air or infinite baffle design is the way to go.
  
  

Choosing an Enclosure

• Before you build the box, also consider the consequences of making it too big or too small. An undersized box will give you a boomy sound, with more mid-bass than low bass, but it will probably take less power to drive it. The size isn't as important in a sealed system as one that has a tuned port but you can stuff your enclosure with fiberglass, wool or polyfill to make it feel up to 40 percent bigger to your speaker. An oversized box will give you deeper and tighter bass but it will also sound drier. Bigger boxes also take more power to drive. A vented enclosure might result in resonance ringing. The best material to use, according to DIYSubwoofers.org, is MDF or 3/4-inch plywood. Brace it asymmetrically on the inside to minimize flex and resonance.
  
  

Finishing Touches

• The easiest way to dress up your enclosure is by covering it with carpet or vinyl. Carpet is probably better if you want the box in your trunk because it offers better protection and wear resistance than vinyl. If you'd like to put the enclosure in your car, vinyl is available in hundreds of colors to match your car's interior. Consider trying gluing raised logos to the box before covering it with vinyl. Other fabrics are also available and you can add a Plexiglas window or lighting.