Technology

QSC K Series Loudspeakers Review

P.A. SYSTEM THAT'S COMPACT, LOUD AND VERSATILE 6/24/2010 2:40 PM Eastern

The K Series line offers three main cabinets and an optional sub.

I’ve used QSC’s HPR 122i powered speakers for several years in portable P.A. applications and have been impressed with their performance. So last year, when QSC debuted its K Series lightweight powered speakers, I was curious to hear them.

The K Series is offered as DSP-driven, powered two-way systems with 8, 10 or 12-inch woofers, 1.75-inch compression drivers on axisymmetrical waveguides and 500+500 watts of Class-D amplification. Other than increased bass response from the larger woofers and a 2dB overall SPL output change, the main difference in each is dispersion angle: K8, 105 degrees; K10, 90 degrees; and K12, 75 degrees. The two-way cabs are molded ABS with steel grilles, multiple M10 fly points, recessed aluminum handles and Tilt-Direct™ pole sockets that adjust for a 0- or 7.5-degree downward tilt. The optional KSub powered subwoofer has two 500-watt amps driving dual transverse 12-inch drivers in a compact, fourth-order bandpass birch plywood enclosure.

Onboard DSP on all systems provides GuardRail™ driver/amp protection, precision crossover action, DEEP™ (Digital Extension and Excursion Processing) LF transient control, and complex FIR and IIR filters with time/frequency/amplitude optimization.

ON THE ROAD
I tested a system with two K10s and the KSub. The K10 has a flexible input panel and can mix two input sources (one switchable XLR combo mic/line input and a line input with combo XLR and RCA jacks) via two recessed gain pots and a post-gain line out for feeding the KSub or a second K10. A series of arrows silkscreened on the panel is designed to make this easier to understand, but it left me (and several other people who used the system) more confused. A couple typos in the manual—referring to “female direct output XLRs” when they’re actually male—didn’t help either. It all became clear a couple minutes later. Ironically, most users will never use the onboard mix functions anyway, although they’re nice to have just in case. (Note: QSC has since changed the panel to make them more clear.)

I first used the two K10s alone (no sub) for vocal reinforcement for a band in a fairly live medium-sized room. Volume-wise, the K10s had no problem keeping up. I was surprised by the output of these little (20.4x12.6x11.8-inch) 32-pound boxes. Kicking in the DEEP switch offered a nice bit of bass extension, and the 90-degree dispersion was even and smooth, with no off-axis roughness. Using the 7.5-degree downward tilt on the pole mounts kept the sound where I wanted it. The K10s have no locking screw to keep the speakers from rotating on the pole mount, but a little duct tape on the pole took care of that—not exactly elegant, but it worked.

Next up was checking out the full system with the KSub. Tilt the KSub back and it moves easily on its large casters. An included pole threads securely into the sub to support a two-way box. Plug in a locking (or standard) AC cable, switch the K10 to “external sub” (100Hz highpass crossover), run an XLR cable between the two, and you’re ready to go. The KSub has switches for a DEEP circuit and polarity reverse for tweaking phase. If I were impressed with the K10s alone, adding the KSub created a monster, with huge—yet damped and controlled—bass. It’s hard to believe this much LF can emanate from a 26x14x28-inch, 74-pound enclosure. A friend of mine later tried the system for a portable DJ gig and was totally hooked.

GIVE IT A GO?
Overall, the K system is a winner. The versatile top boxes easily handle smaller events alone or bring in a sub (or subs) for larger shows, and the axisymmetrical waveguides make the K10s ideal for doubling as stage wedges. Setup is fast, and they’re loud, with an even, flat response throughout the listening area. Thumbs up on this one!

Click on the Product Summary box to view the QSC K Series product page.

Click on the Product Summary box to view the QSC K Series product page.