Pump Up The Bass: More About Subwoofers
The bass is the ‘.1’ in a 5.1 surround sound system. For such a little number, it’s very important for your home theatre audio. Some may even say crucial. The bass is the part of the soundtrack that moves you - literally. When you sit in a theatre and a bomb goes off or the thunder rolls, the lower parts of the sounds are what set up the vibrations that travel around your body, enhancing that feeling of being part of the action. It’s also the part of the sound that has the potential to shake your downstairs neighbor’s china off the shelves or set off the alarm of that car parked across the street.
A separate speaker for the bass sounds on a soundtrack is called a subwoofer. The lower frequency sound waves use a larger diaphragm to move the amount of air it takes to make these sounds. While your smaller speakers can sometimes produce these lower frequency waves, they won’t have the earthshaking quality that you get when you are sitting in a theatre, and your system may end up sounding a bit ‘tinny’. Some of your larger home theatre speaker towers are capable of handling this part of the soundtrack, but then you are taking power away from the woofers and tweeters used to produce the mid and high range frequencies.
Now, sound systems can get incredibly complex. If you aren’t an audiophile but still want good sound, it’s not a problem. There are many systems out there that give you a lot of options with simple controls. One of the important items you want to look at is your subwoofer. You want to ask yourself whether a passive sub will work or if an active woofer would be better. A passive subwoofer means that is doesn’t have its own power supply. The lower frequency sounds need a lot of power to sound good. A passive subwoofer uses power from the same amp that’s driving the other home theatre speakers. While you can control the volume from the amplifier, there is less control all around. An active sub has its own power supply and, often, its own volume controls. This means that the signal received from the amplifier/receiver is pumped up by the subwoofer itself, without taking any of the power from the other speakers.
The placement of the subwoofer is the next important decision you need to make. Actually, the placement of all your home theatre speakers is important. You first need to decide where you will be enjoying your movies and games from. If you have enough space, a couch or chair located in the middle of the room is your best bet. That way, the sounds coming from your rear speakers are actually coming from behind you. Don’t worry if that option isn’t available, your system can still sound good, especially if you are able to hang the rear speakers up in corners of the room.
The subwoofer is more forgiving. Bass sound is omni-directional, which means that it goes out from the speaker in all direction, at least for the most part. The best tool to use when you are getting system set ‘just so’ is your own ears. Here’s an easy trick. Place your subwoofer in the same position that you’ll be sitting in. If you can, it might even be a good idea to lift the woofer up to about where your head would be. Now, move around your room and listen. If you plan on leaving your sub on the floor, crawl. When you find the spot that the bass sounds best, move your subwoofer to that location. Since the sounds are going out and bouncing around the room in roughly the same direction, the sound should be great when you get it into place.
There are a couple of other things to keep in mind, like the aforementioned downstairs neighbors. While the walls, ceiling and floor will stop the higher frequencies from leaving the room, they may actually increase the volume of the lower range sounds. We’ve all heard the guy driving down the street with the volume pumped up on a sound system that probably cost more than the car. All you hear is the bass. Try to keep that in mind so the cops don’t show up in the middle of your favorite movie or game.
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