How can this be? The answer involves two important BG Radia design decisions. First, by using many small bass drivers (48 x 4-inch units) rather than a few much larger and more massive woofers, BG Radia has produced a woofer that not only moves huge quantities of air at low frequencies but that—quite remarkably—offers flat frequency response all the way up to about 4.5kHz (a claim few if any other subs can make with a straight face). Second, BG Radia’s THX Balanced Bass Line cabinets effectively eliminate problems with cabinet resonance, which can be a huge problems with many box type subs. Even when the BGX-4850 is belting out powerful deep bass, you can put your hands on the BG woofer enclosures and pretty much feel, well, nothing at all. Though I admit that it initially seems a bit strange, it’s a wonderful thing to experience powerful and articulate bass with no cabinet shakes, quakes, or bad vibes of any kind.
I’ve experienced many good (and some great) subwoofers that would play loud-‘n’-low when movies soundtracks so required, but I don’t think I’ve ever experienced a bass system that combined output, extension, speed, and clarity as effectively as the BGX-4850 does. And on some soundtracks this proved an out-and-out revelation. Long term Playback readers know that I’m fond of using The Strangers as an A/V test disc, but once I plugged the BGX-4850 rig into my reference system the BG Radia woofers started revealing things I’d never heard before (at least not so clearly) in the film’s soundtrack. For instance, in the “Back Again” sequence, when Kristen McKay (Liv Tyler) is left alone in the summer home and confronts the creepy return of the strangers, the sound designers symbolize the immediacy of the threat through the hard, sharp, low frequency sound of loud knocks on the front door in the middle of the night. These the BG Radia system reproduced with startling acuity and force. But to suggest the mounting eeriness of the whole scenario, the soundtrack also presents richly textured very low frequency “washes” coupled with the mysterious, deep ringing sounds of what appear to be giant temple bells or gongs. The sounds are fairly loud but also so low-pitched that some subs miss them (or at least their lowest layers), but through the BG system they were oh-so-clear and dark, deep and ominous enough to send chills up my spine.
Another film that I find provides a great subwoofer workout is Clint Eastwood’s classic Sands of Iwo Jima. I’ve often commented on the visceral power of the scenes where Japanese soldiers are hunkered down in their island caves while we hear American artillery shells exploding overhead. These scenes have always been effective in the past, but rose to a whole new level of excellence with the BG Radia subwoofer in play. Here’s why. Normally, with standard subs in the Playback reference system, you’ll hear the “boom” of a shell going off followed a split second later higher pitched textural sound of dirt and debris raining down from the roof of the cave. This is all well and good, but what I had not realized—until the BG Radia system came along—was that there was something missing: namely, the abrupt, ultra-low-frequency, slap-in-the-face concussion that results when any explosion occurs. With the BGX-4850 system in play, though, I could not only hear but feel the concussive jolt as shells landed, followed in infinitesimal split-second by the booming after report of the explosion. This may seem a small distinction, but it’s one that shows how the BG Radia system’s combination of raw power and transient speed can dramatically enhance realism.
In many cases, I suspect, audiophiles are inclined to dismiss in-wall subwoofers as inherently flawed designs, which make it all the more ironic that BG Radia’s in-wall subwoofer system has proven to be one of the most musically satisfying audiophile-grade subs I’ve ever heard. (Two of my other favorites are the critically acclaimed JL Audio Fathom-series subs, which Playback uses as its reference, and the Wilson Benesch Torus Infrasonic Generator). What makes the BGX-4850 system click, really, is again that mellifluous combination of bass extension, power, resolution and speed.
In may cases, audiophiles prefer to cross in subs (if they use them at all) at very low frequencies, so that the subs won’t spoil the timbral purity of their main speakers and you can use the BGX-4850 system in that way and with excellent results. But frankly, BG Radia’s system is so fast and transparent sounding that you can also use what are, by audiophile standards, much higher crossover frequencies—such as 60 or 80Hz—without losing bass clarity or focus. As an experiment, I tried using the BG-Radia system with both low and high crossover points, and got very good results in both cases.