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BG Radia BGX-4850 Review

August 10, 2009 By Gary Altunian

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BG Radia BGX-4850 Review
BG Radia BGX-4850 Review
BG Radia BGA-2104 Power Amplifier/DSP Equalizer Controller

Extreme Bass
Or: What happens when you put 48 Subwoofers in a wall

BG Radia and THX, with the BGX-4850, have developed a subwoofer system that neatly overcomes many of the acoustic problems with getting good bass in a room and produces deep, extended and well-distributed bass that sounds tight and solid with music and movie sources.

And they did it with 4-inch drivers. Ok, a lot of 4-inch drivers.

BG Radia BGX-4850 Review

If I learned to play just one musical instrument, it would be the acoustic bass. I love bass—deep, solid, tight, extended bass. Soft, flabby bass just annoys me. So does so-called ‘“one-note bass.” If the bass isn’t right, nothing sounds good

For various reasons, getting good bass is one of the most difficult challenges in setting up a stereo or home theater system. For example, bass frequencies cause walls, floors and every object in a room to vibrate, and each of these things creates their own sound, coloring the sound of the bass. Bass frequencies also create room nodes, areas where sound waves collide to amplify or attenuate the bass at certain frequencies. This leads to uneven peaks and dips in bass response depending on your listening position.

Carefully chosen speaker and subwoofer placement is one solution, although it is difficult to achieve the best bass. Another solution, though often somewhat aesthetically unappealing, is room acoustic treatments.

Of course, there is another way...

How to Install 48 Subwoofers in a Wall

The BGX-4850 is designed as an in-wall subwoofer system, although an in-room option is in the works. The system consists of four SM-1250 subwoofer modules and an outboard amplifier, the BGA-2104, to power the modules. Each sub module has 12 4-inch drivers arranged in pairs that result in totally vibration-free performance, which is critical for in-wall installations. Each woofer is isolated in its own chamber.

These chambers are made of BMC (bulk molding compound), a strong, dense material widely used in automotive and electronics applications. BG Radia and THX claim that the 48 4-inch woofers have the equivalent surface area of two 18-inch woofers. Based on my listening tests, I can’t dispute their claim.

The woofers are arranged in pairs that face each other and thus cancel vibrations caused by the motion of the woofers. Vibrations are almost undetectable even when touching the metal frame that houses each bass module. Vibration-free performance is critical for room isolation and to prevent wall rattles.

The modules can be installed in existing walls or in new construction and are sized to fit in 3 .75-inch deep standard residential walls, with 16–inch, on-center stud spacing. BG Radia offers a 15–inch-wide grille for retrofit installations and a 7–inch-wide grille for new construction. Each grille is available in black or white and can be painted to match almost any room décor.

 BG Radia BGA-2104 Power Amplifier/DSP Equalizer Controller

The BGA-2104 is an ICE-powered digital amp with 2 x 1100 watts and DSP equalization. There are also several custom installation features, including an RS-232 port for home automation control, balanced-line XLR and unbalanced-line RCA inputs, 3.5-millimeter IR inputs and a +12V trigger function.

A single front panel knob controls various performance aspects of the system. The knob adjusts output level, music or movie mode, crossover frequency (including bypass), phase, input select and input sensitivity. The rack-mountable BGA 2104 comes with a small remote to control power and level, and to select music or movie modes. The amp also features two Speakon speaker connectors, which are used in professional applications and have a locking feature to prevent the cables from coming loose.

Bass-ic Solutions

I set up the BGX-4850 with two of the modules on the front wall and two on the rear wall, all facing into the listening room—a setup recommended by BG Radia and THX. I set the BGA-2104 to bypass mode with the pre-amp crossover set to 80Hz. For starters, the volume was set at -5dB.

BG Radia BGX-4850 ReviewNext, I put the BGX-4850 through its paces using music and movie sources that have the best and sometimes the most difficult bass to reproduce. Undeniably, the BGX-4850 is one of the best subwoofers I’ve ever heard, anywhere.

I started with Lyle Lovett’s “She’s Already Made up Her Mind” from Joshua Judges Ruth, a multichannel DTS CD with extremely dynamic bass content. The BGX-4850 had outstanding bass extension, with absolutely no heaviness or boom—just solid, deep bass.

It also filled the room with even distribution of bass, eliminating any sensation of localization. With little adjustment, the four subs blended seamlessly with the rest of my system.

Remarkably, the modules were merely leaning against the wall and the bass sounded excellent. Given my crude “installation” I predict the in-room version of the BG sub will also perform very well.

I had to experiment a bit to fine tune the position of the four modules to eliminate some occasional bass cancellation in a few locations, which happens with any sub, but once dialed-in, the results were extraordinary, even exhilarating.

The only difficulty I encountered was the input sensitivity control on the BGA-2104 amp, which required a few adjustments to prevent clipping of the amp’s input. Once adjusted correctly, though, it was no problem.

Another punishing bass test is Steely Dan’s “Babylon Sisters” from their Gaucho album (SACD and/or DTS CD). The entire disc is recorded with a lot a bass EQ, especially the bass and the kick drum. The bass sounded tight and strong. The kick drum smacked me in the chest when played at high levels, the only way to listen to this disc. You can’t ask much more from a subwoofer that sounds this good.

On to movies...


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