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Speakers: A Quick Look at Subwoofers By: Charlie Schmuck May 28, 2010 Woofers, in the audio world are not a cute puppy that barks. Woofers are speakers that give you low frequencies that can rattle the pictures off your walls and annoy the neighbors. You may have even heard of a subwoofer. But, what is a subwoofer, and why do they matter? First, a woofer can be best defined as: an individual speaker found in home theater sound systems that processes bass sounds. The woofer is used in an audio system for just that- it processes the lower drums, bass guitar, tuba, and random explosions from your favorite action movie. All of these sounds are handled by the woofer (or even better- the subwoofer). If a speaker produces frequencies between 15Hz and 80Hz, then it’s a subwoofer, the rest are just woofers- regardless of what the package says. A subwoofer is a woofer that produces those lower frequencies, and it is powerful enough to push air. That may not sound like a big deal, but it is. Do you want to hear the drums? Then use a woofer. Do you want to feel the drums? Use a subwoofer. Even those idiots that pull up next to you in traffic, booming away with their barely intelligible music are using subwoofers. In your car, it’s loud, annoying, and it may make some parts of your car rattle. Inside his car, it’s like being inside of a trash can rolling down a hill- and probably sounds about the same. The reason is that those large speakers (usually around 10-15” in diameter) are pushing enough air to make you actually feel it. On top of that, the frequencies those speakers produce are actually creating sympathetic vibrations that make things rattle. Sympathetic vibrations, its physics, enough said. So, now it’s settled, subwoofers are better. As mentioned previously, most of the square boxes you buy in those all-in-one theaters are woofers, and they aren’t worth it. If you have one of those in your system, go buy an inexpensive subwoofer, and it will make your system sound so much better. So what subwoofers do you choose? There even different types of those things. And you thought physics was complicated! Before we get into that, you have to know what a crossover is. A crossover is a piece of electronic gear that only lets certain frequencies pass to a speaker. When a speaker vibrates to create a sound, it does this at a certain speed (frequency). Smaller speakers (tweeters) can vibrate really fast, giving you those higher sounds, but the lower frequencies will not come out as clear, and it will sound terrible. The larger speakers can produce the clearer lower frequencies, and anything at a higher frequency will sound muddy. A crossover will cut out the higher frequencies (on a subwoofer) to protect the speaker, and give you better sound, and better efficiency. So now, the first thing you have to decide is whether to get an active subwoofer or a passive subwoofer: A passive subwoofer is just a speaker and (sometimes) a crossover in a speaker box. If you have a passive subwoofer, you will probably need a subwoofer amplifier for it, unless you have a really beefy receiver. If that’s the case, stop reading. You know enough about audio that you won’t learn anything new in the next few paragraphs. An active subwoofer will have the speaker, a crossover, and an amplifier built in to one box. For most surround sound systems, this is a typical installation. This is the easiest installation, and the best all-around solution. Okay, so once you have decided on an active or passive subwoofer- you have a number of options to choose. What diameter size of the driver? Size, in this case, does matter. Is the driver made from, paper, Kevlar, aluminum, wood, or polypropylene? I am sure someone has made one from Illudium Q-36. Plus all the cosmetic choices- color, shape, etc. You have a wide selection to choose when you purchase a subwoofer. Choice is good. Subwoofers normally come in sizes that range from 8” to 15”. Generally speaking, the smaller subwoofer will ‘hit’ harder- delivering more punch. The larger subwoofer will have more ‘effect’ creating greater vibrations, and earth shattering noises. Now understand, these are generalities, if you have the money you can buy an 8” subwoofer that will create so much noise that it will turn your brain to mush. In our home installations, we normally take the middle road, and install 10” or 12” subwoofers. It’s the happy medium between the ‘hit’ which is better for music, and the ‘effect’ for better sound reproduction in movies. But there is also another thing we have to consider when choosing a subwoofer; we call it the ‘wife factor’. Most of our surround sound installations are in multi-use rooms, such as family room, or rec-rooms. Usually, the lady of the house does not want to see a giant box sitting in the corner of the room. To them it’s ugly, even though it may sound awesome. So, we have found that the smaller 10” driver subwoofers are easily hidden in cabinets, or behind other furniture. They provide the bass needed for surround sound effects, but can be kept out of sight while keeping the wife happy. Sorry, I know it sounds sexist, but it’s the way things normally work doing home installations, and our goal is to make the client happy first, even though selling a massive Earthquake subwoofer would make us more money. Just as important as what type of subwoofer you decide on, is where you are going to place the subwoofer. There are tons of options. You can install them in the wall. You can install them in the floor. You can hide them inside your equipment cabinet. Or, you could be normal, and sit it in corner of your room. Where you place it will obviously affect which subwoofer you choose, but speaker placement is an art, and that will require another posting on where, and how, you should place your speakers. So hopefully you now understand why having a subwoofer is important. If you want so impress your friends with your awesome home theater, don’t forget about that speaker in the corner of your room. Life without a subwoofer is like watching a movie on that old non-HD TV in your garage. It gets the job done, but it’s just not the same. |
