Dolby surround and center channels/subwoofers

Week of February 26, 2006

Q: Are a center channel and a subwoofer necessary for Dolby surround sound?

-Art Dervaes, State College, PA

A: Necessary? No. Prefereable? Usually, but not always.

You can get satisfying surround sound without a center channel and/or a subwoofer, meaning only four speakers, front left-right and surround left-right, are used to create all the sound. To create surround sound with four speakers, you simply set the subwoofer setting on your receiver to “off” or “no subwoofer”, the center channel setting to “no center channel” or ‘phantom” and the front speaker size to “large”.

When readers write to me for system recommendations I frequently recommend that they forego the center speaker and subwoofer, depending on their budget, their system goals, and how their system will be used. By using your entire speaker budget to buy four speakers (most of it allocated to the main front speakers), you will often get better sound than buying six or seven mediocre speakers that cost the same amount. The center and sub can always be added later, and in the meantime you enjoy superior sound quality because you have purchased better speakers with the money on hand at the moment.

In a system where music-playing performance is all-important, the front speakers are absolutely critical and perhaps even more reason to follow this formula. Foregoing the subwoofer and center channel at first allows more money invested into larger, better-quality tower speakers for the front left/right channels. If you shop carefully this will pay large dividends in sound quality.

When you turn off the subwoofer setting on the receiver, all the subwoofer information is sent to the main speakers. The larger, more expensive speakers will produce ample, satisfying bass with movies and music even though you do not have a subwoofer, though you are not likely to shake the walls with the sound effects.

When you set your receiver to “no center channel” it takes the center channel information and mixes it equally into the left and right speakers, creating a “virtual center channel” that seems to appear halfway between the front speakers- typically, over your TV screen. Some listeners prefer the sound without the center channel- myself included. I think using the two main speakers to create the center channel info sounds more open and natural. I have two permanent surround-sound systems in my home and I have never missed the lack of a center channel.

Many argue that the center channel speaker is the most important speaker in a home theater. To me, this is even more of a reason to wait and buy a really super one, or let the two main speakers do the work between them rather than delegate it to a small box sitting on your TV.

There is also the matter of simplicity. Four speakers are easier to place and balance than five speakers and a subwoofer. The subwoofer balance is especially critical- many home users have difficulty placing and setting a subwoofer so it seamlessly integrates into the sound of the main speakers. Remove the subwoofer, and the problem disappears.

If you have the money to buy all the speakers at once and buy top quality, by all means go for the sub and probably the center channel and be done with it from the get-go. But to sum up this column, if you have front speakers and want to enjoy surround sound, all you need is two more speakers for surrounds duty, making it easy and inexpensive for anyone to enjoy surround sound. And if you want the best possible sound quality and are willing to take your time to get it, invest as much of your speaker budget as you can into your front speakers and add the center and the subwoofer later.

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