Small speakers and sound quality

Week of October 23rd, 2005

Q: In a recent column you comment that you operate your own home system with large front speakers and forego a subwoofer. I also took notice when you wrote on your website that, even with a subwoofer, the front side speakers need to be big enough to handle the upper end of the low frequencies that the subwoofer doesn’t reproduce faithfully.

I currently have two 18-year-old big JBL towers that sound GREAT but are decor-busters (big, dark wood – both natural enemy of wives). I’m moving towards “modernizing” along the lines of a more contemporary setup with smaller side speakers and a subwoofer, but your writings have made me wonder about that idea, or at least made me want to get some answers before leaping into anything.

I have two questions: First, how big (woofer diameter) would a speaker have to be to comfortably eliminate the need for a subwoofer? Second question: How big should a speaker be to adequately reproduce all frequencies in the case where a subwoofer IS engaged?

-Jim Rosenow, Shoreview, Minn.

A: Regarding you question about woofer diameter, it depends on the speaker itself, your room size and acoustics, the speaker placement, and your listening tastes. Before I go into more detail, I should probably qualify my statement a bit.

If you take the average consumer and put a pair of tower speakers using six-inch woofers on either side of his TV, the improvement over the TV’s speakers will be HUGE and he will be really happy- and music will sound great, too. Audiophiles and home theater buffs usually want more. If you want the earth to shake, you pretty much need a subwoofer or very large tower speakers. But if satisfying, full sound is your goal, a pair of good-quality towers will suffice.

Rather than consider woofer diameter when choosing speakers, look at the specification called frequency response. You will see a specification such as 38hz-20khz. The first number is the lowest bass frequency the speaker can solidly reproduce. If this number is below 40, the speakers should provide satisfying full-range sound without a subwoofer, even for movies- but don’t expect the ground to shake!

Your second question,”How big should a speaker be to adequately reproduce all frequencies in the case where a subwoofer IS engaged?” opens up a subject near and dear to my heart, one that regular readers of my column will be familiar with: the inadequacy of teeny-tiny satellite speakers.

If you want really good, full-range and solidly-bodied sound… you need bookshelf-sized speakers at a minimum. To make sound, speakers have to move air and tiny speakers can’t move enough air to reproduce upper bass and lower midrange frequencies well. Turning the subwoofer frequency up to match the small speakers is a band-aid approach that not only does not do the same job, it can lead to deep voices echoing out of the subwoofer!

To answer your question directly, the lowest frequency that human voices hit is 80hz. For the best quality sound a speaker should go down in the bass to 80 hz at the minimum, and preferably 55-60 hz. This usually means a bookshelf-sized speaker with a 5 or 6 inch woofer.

The tiny speakers that come in a system typically only go down to 120 hz at best, all the way up to an obscenely high number like 200hz or more for the tiniest of the cube speakers, some of which are extremely expensive!

This is not to say that you can’t get good sound with tiny speakers. Polk Audio and Paradigm make good-sounding small systems, and Atlantic Technology has a home theater system called the System 920 which uses a four-inch woofer that reaches down to 100hz, excellent for a small speaker. The company has an excellent reputation and the System 920 has received outstanding reviews. I may try one myself sometime as I would love to find a small system I can rave about! The System 920 is priced at $899 and can be seen at

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