Flatness is what it's all about today when you go shopping for home theater gear - and I'm not talking frequency response. Now that plasma and other flat-screen TVs rule, depth - the kind measured in inches - has become the kiss of death for anything that might share the light from the screen, like speakers.

Fast Facts DRIVER COMPLEMENT L5 satellite 1-inch dome tweeter, 3-inch cone midrange, two 5 1/4-inch cone woofers U2 subwoofer 12-inch cone DIMENSIONS (WxHxD) L5, 7 3/4 x 21 3/4 x 5 5/8 inches; U2 sub, 14 x 14 x 14 inches; X1 crossover, 17 x 2 1/8 x 11 1/2 inches; A1 amplifier, 17 x 2 1/8 x 11 inches WEIGHT L5, 18 pounds; U2 sub, 38 pounds; X1, 9 pounds; A1, 18 pounds ENCLOSURES sealed SUBWOOFER POWER 250 watts INPUTS/OUTPUTS/CONTROLS L5 and U2 sub, multiway binding posts X1 crossover, RCA and XLR line-level main and LFE inputs, subwoofer and high-pass outputs; continuously variable master-gain, low-pass, phase, Boundary EQ, and LFE-gain controls; selectable high-pass frequency (50, 80, 110 Hz); DC-trigger; stereo/mono sub selector A1 amplifier, RCA and XLR line-level inputs; DC-trigger; speaker-level output FINISH L5, anthracite, silver, matte white; U2 sub, anthracite matte lacquer; X1 and A1, anthracite PRICE L5, $500 each; U2 system (two U2 subs, X1, A1), $1,400; total, $3,900 MANUFACTURER NHT, www.nhthifi.com, 800-648-9993

Or so it seems. Even an iconoclastic company like NHT - whose think-different, modular Evolution M5 speaker system impressed me so much that it got an S&V Reviewer's Choice Award in 2002 - is not immune to the trend. NHT's new Evolution L5 speaker, while far from the flattest I've seen, measures just 6 inches from the front of its cloth grille to the back of its wall-mounting bracket - a nifty, click-stop affair that can aim the L5 at any angle your installation requires.

In fact, the L5's drivers are nearly identical to those in the M5 satellite of the earlier Evolution system, re-engineered into a sleek, aluminum half-cylinder. NHT sent five L5s for the main channels, plus its four-piece U2 subwoofer system (photo on facing page): two passive subwoofers, each a 14-inch cube with a 12-inch driver, a slim A1 mono subwoofer power amp, and the similarly sized X1 crossover/controller.

Installing and connecting all the pieces of the U2 is more involved than hooking up your typical powered subwoofer, plus you need space for its two electronic components. But the system provides unmatched flexibility, with no fewer than five controls on the X1 to fine-tune subwoofer and crossover characteristics, including adjustable boundary compensation. You could experiment with placing the two subs in dissimilar locations, which some people believe can help smooth out the deep bass, though I've found little if any benefit over simply stacking two subs in my preferred location.

I started by connecting my receiver's subwoofer line-level output to the X1's RCA line input, then the X1's subwoofer output to the A1's input and the amp's single speaker-level output to the first U2 subwoofer. A pair of dual-banana jumpers on the first sub served to connect the second.