The Science of Subwoofers

When surround sound systems came out, everyone became familiar with what 5.1 meant–five speakers dispersed around the room and the “.1” was the subwoofer, centered down low and in front.

But there is a science to subwoofers that create those deep, rich, bass acoustics beyond what can be delivered by a single speaker.

The single subwoofer approach suffers from an unevenness in bass which is to say it is impossible to get smooth bass response in a home theater or media room from seat to seat. While one seating location might be outstanding, the other seats would suffer from bass peaks or dips…in other words, depending on the bass frequency, either too loud or too quiet.

Dr. Floyd Toole and Todd Welti have together been an invaluable asset to the home sound reproduction industry doing a lot of experimentation with subwoofer placement, numbers, and bass sound quality. This breakthrough work on bass reproduction has allowed us as home theater designers to create a room where we can significantly minimize bass response problems. Their whitepaper on the topic was the end-product of countless tests and acoustical models of playing with multiple subwoofers in different locations in a room to improve bass response over a much wider listening area.

In the end, Toole and Welti concluded that there are three ideal configurations for maximum bass reproduction.  They are listed here in order from optimum to acceptable:

  1. Have four subwoofers with one located at the midpoint of each of the four surrounding walls. This configuration displayed the least amount of variation in bass response from seat to seat.
  2. As an alternative to the above, locate the four subwoofers in each corner of the room.
  3. Yet a third alternative is to have only two subwoofers; one centered on the front wall and the other centered on the rear wall.
You might be wondering how ugly a home theater can look with four subwoofers taking up space in the room. The good news is that there are many subwoofer options available today, including good-quality in-wall subwoofers. Hiding technology in an aesthetically pleasing way is something we’re good at.
by Bryan Naquin.  Follow Bryan on Twitter @ACIexperts.  And you can always contact him at 225.906.2589 or by email at bryan@aciexperts.net. Bryan Naquin is president of Acadian Home Theater and Automation based in Baton Rouge, Louisiana.  CEPro Magazine has ranked Acadian in the top 100 consumer electronic companies in the U.S. for the third year in a row.