Your subwoofer is a critical element in your home theater system. The low frequency from the subwoofer is what puts the boom in an explosion, the rumble in a spaceship and the thud in a gunshot. However, even the biggest and baddest subs may not meet your expectations if they aren’t placed and set up properly.

“It’s a classic story amongst Home Theater Professionals – the client spends all this money getting a giant subwoofer to complement the rest of their system. But, when they sit down to watch a movie, the person next to them complains about too much bass, while others feel the bass is too weak.

– John Dahl, Director of Education at THX Ltd.

It could simply be a difference in personal preference, but more than likely it’s the room itself that is the root of the problem.

Room Modes

In layman’s terms, a Room Mode is how a room’s dimensions change the bass coming from a subwoofer. The frequency at which a room resonates directly correlates to its dimensions, acting much like a giant pipe organ. The result can be a change in both bass volume and tone as you shift your listening position from seat to seat.

How do you Test for Room Modes?

To identify Room Modes, begin by placing the subwoofer in the corner of the room and play either music or a movie with lot of bass. As you move from seat to seat, listen for volume and tone changes. A rectangular room made of heavy rigid construction like concrete or cinder block materials will exhibit fairly obvious effects – you may even see a pattern, where the volume dips and peaks throughout the room. If lighter weight, more flexible construction materials such as dry wall are used, or the room is large and open, the effects will be less obvious.

If you’re looking to identify and correct bass mode problems, THX recommends you consult a THX Certified Professional.

Recommendations for Reducing Room Modes

• Set up your home theater system in a more bass friendly room or build a better room. (Don’t panic, any room can be made to sound good)
• Place the subwoofer(s) at a spot in the room where they reduce the amount of peaks and dips in bass response (Good subwoofer placement can be very complex)
• Move the seats so they are not in a peak or dip (often a foot or so will do the job)
• If your budget/space allows, use more than one subwoofer to balance the bass from seat to seat
• Use acoustic treatments specially designed to control bass (These are highly specialized items which may require research)
• Equalize by pulling down the bass mode peaks only

Note that equalization is the last item on the list. Equalization works best if all the other solutions are applied first.

THX Certified BGX-4850 In-wall Subwoofer

Most of us have experienced deep bass rattling walls, windows and doors in the home and car. THX Balanced Bass-line provides the ability for speaker manufacturers to deliver big-box bass performance—minus the vibrations.

THX Balanced Bass-line breaks the mold of traditional subwoofer designs—getting the sub out of the big box. The technology places small, micro-precision woofers face-to-face, arranged in balanced pairs. This approach force cancel vibrations, ensuring deep low frequency performance without vibrations discoloring soundtracks or intruding into adjacent rooms.

THX Balanced Bass-line Features

• Tight Bass Performance: Experience natural sounding bass exactly like it was recorded, without shaking the walls loose.
• Shape Shifting Designs: THX Balanced Bass-line allows speaker manufacturers to produce very natural, vibration-free bass from smaller, more stylized systems.

The BG Radia BGX-4850 Subwoofer System

THX Balanced Bass-line was first introduced in the BG BGX-4850 in-wall subwoofer for custom home theater installations. The BGX-4850 consists of four separate in-wall bass modules driven by the BGA-2104 rack-mountable power amplifier/DSP equalizer controller. Each bass module contains twelve micro-precision woofers, each sealed in an airtight enclosure, and arranged in six balanced pairs. The four modules have a total radiating area equal to two 18 inch drivers, yet fit completely inside a standard 2×4-inch stud-wall.

Hailed by critics and audiophiles alike, the BGX-4850 won “Best of CEDIA 2009” and the 2009 CEA Mark of Excellence Award.

Available Now

The BGX-4850 is currently available to order from your BG Radia representative. Visit BG Radia for more information.