Should I Buy A Subwoofer?
The decision to buy a subwoofer for your PA system is one requiring well-informed thought. Subwoofers are not for everyone, and even if you choose one it must fulfill all of your requirements. Subwoofers are essentially large speakers designed to reproduce extended low frequencies, often as far down as 30Hz or lower but rarely above 300Hz. If you already knew this than the mere fact that you're reading this article probably means you need one, as you're most likely outgrowing your setup and are looking to add some extra "boom" to your less-than-adequate system. In that case, congratulations, your band is getting popular and needs a larger system to cater to larger audiences. If you didn't know this, you may not even have a PA system and are deciding whether or not you should spend the extra cash from the get-go. We'll discuss both these scenarios and more.
A subwoofer is probably not necessary for single musicians, sole public speakers, and new bands performing in small venues. Your typical entry-level PA system is most likely more than adequate to get you started. That being said, however, a little extra bass goes a long way for certain types of music. Hip hop and Drum n' Bass music relies heavily on deep, earth shaking sounds. DJ's and bands performing in these and other similar genres should probably consider a subwoofer. Even public speakers with deep voices may still want to pay attention.
Subwoofers ease the workload on your main speakers by taking the low-end load off of them, delivering low frequencies that your system was never designed for to begin with. You'll me more than surprised to hear a fuller, cleaner sound after adding one. Adding a subwoofer to an existing PA system often means you can run the PA at a lower volume while still maintaining a "full" amount of sound.
Does your existing system sound tinny? Does it crackle or otherwise sound distorted, especially during those moments when a heavy bassline or someone with a loud, deep voice starts shouting? Subwoofers help deliver professional-grade volume without straining your other speakers. Aside from a terrible performance, nothing is more annoying to a crowd than speakers that suck.
If you are lucky enough to be addressing a large crowd, the expense of adding a subwoofer should not stop you from buying one, as it will more than pay for itself in high approval ratings from your fan base. The considerations most likely to be made at this point is what kind, what size, powered or unpowered, etc. Keep in mind that subwoofers by nature are large and heavy, as they are designed to broadcast low tones that are difficult to produce. That means you'll be lugging around more heavy equipment from gig to gig.
JBL and Mackie produce excellent subwoofers for these applications. Behringer, Peavey, and Yamaha are also top choices. Choosing a particular make and model will ultimate come down to price, venue size, type of performances you will be giving, the logistics of lugging around and storing it, and whether it will be added to a pre-existing system or purchased together with a completely new setup.