REL T5 Subwoofer
Small Acorn, Big Tree
In a 1970s television commercial, storm clouds brewed and thunder rolled ominously after an embarrassed Mother Nature tasted Chiffon margarine and pronounced it butter. “It’s not nice to fool Mother Nature,” admonished the announcer, Mason (“with a name like Smucker’s”) Adams.
When it comes to reproducing massive explosions, close-up whirring helicopter rotors, the lowest organ stops, and large-space room rumble, there’s no fooling Mother Nature. Producing deep, gut-socking musically convincing low frequencies that you can feel as well as hear typically requires compressing large volumes of air. That usually calls for a big woofer in an even bigger cabinet capable of compressing and rarefying the large amounts of air required to pressurize a room.
That does not mean—as one audio writer mistakenly wrote—that you can’t reproduce 20 hertz in a room less than 55 feet long, which is the approximate length of a 20-Hz sine wave. “20 Hz won’t fit!” he wrote. “The wave will crash into the wall and break up,” he figured. Nonetheless, producing deep, linear bass in smaller rooms is problematic.
Nor is there any reason that a small box can’t produce very low frequencies (though often at only modest volumes before distortion runs rampant). Many long-throw, small-driver, small-box subwoofers can produce reasonably low frequencies down to where sound is felt as much as it’s heard. More than a decade ago, the development of compact, powerful, longthrow drivers with unusually large, foamy surrounds ushered in a spate of such products. Unfortunately, few of these small fart boxes can truly pressurize a room or be musically satisfying and blend seamlessly with the speakers being called upon to generate the higher frequencies. Most produce low-frequency boom, with musicality going bust.
REL claims that its diminutive T5, when properly set up, can pressurize a room, produce very low frequencies, integrate well with the main speakers, and produce musically satisfying results. In other words, REL says its entry into the tiny subwoofer category can fool Mother Nature.
Thinking Inside the Box
REL’s T5 measures less than a cubic foot and houses an 8-inch downward-firing, long-throw, steel-chassis woofer driven by a gutsy 125-watt RMS Class A/B amplifier. The well-braced little cabinet sits on four aluminum cubes that load the driver to the floor at a specified distance. Claimed in-room response is –6 decibels at 32 Hz, with nominally flat response from 35 Hz to 90 Hz. Other than the lowest organ pedals, the T5 should be able to grab the deepest frequencies produced by most musical instruments and convey the room rumble of all but the largest spaces to a reasonable volume.
But what about pressurizing the room and producing a seamless blend with the main speakers?One of the keys to REL’s claim is its versatile input structure. It includes two separately adjustable sets, one of which includes a variable low-pass filter and both high-level speaker and low-level RCA inputs. However, only one of these may be used at a time. There’s also an RCA jack labeled “.1/LFE,” which provides no low-pass filter but does have its own level control and may be used simultaneously with one of the other inputs if desired.
In addition, there’s a stereo speaker-level Neutrik speakON jack input. REL supplies a 10meter (34-foot, 10-inch) cable with a Neutrik plug on one end and three stripped wires on the other that connect to the amplifier’s left and right hot speaker terminals and one of the two negative terminals. If you’re running a dual-differential balanced (or bridged) amplifier, REL recommends that you connect the ground wire to a chassis ground, not the negative speaker terminal (although REL wisely admonishes you to contact your dealer first).
Because of the T5’s speaker-level input capability, REL recommends that you not set the processor’s front speaker setting to Small even if your main speakers are low-frequency limited. The potential advantage of this arrangement is twofold. First, only the LFE information reaches the subwoofer via the low-level RCA input, and you can independently adjust that level. Simultaneously, when you set the speaker type to Large, the same low-frequency information and bass character reaches both the main speakers and the subwoofer through the speaker-level input, and it too can be independently adjusted. REL believes this produces a more seamless and musical blend. That may or may not prove to be ideal or even workable, depending upon the robustness of your small satellites, but to REL’s way of thinking, it’s worth a try. A variable crossover frequency control adjusts the T5’s high-frequency response limit between 32 Hz and 180 Hz.