QSC K Series Review

Impressive output from lightweight powered loudspeakers. 6/02/2010 8:00 AM Eastern

QSC K Series Review

Jun 2, 2010 12:00 PM, By George Petersen

Impressive output from lightweight powered loudspeakers.

QSC K Series

The QSC K series is offered as DSP-driven, powered two-way systems with 8in. (K8), 10in. (K10), or 12in. (K12) woofers; 1.75in. compression drivers on conical waveguides; and 500W plus 500W of Class-D amplification. Other than increased bass response from the larger woofers and a 2dB overall SPL output change, the main difference between them is the dispersion angle: 105 degrees for the K8, 90 degrees for the K10, and 75 degrees for the K12. 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 7.5-degree downward tilt. The optional KSub powered subwoofer has two 500W amps driving dual transverse 12in. drivers. Onboard DSP on all systems provides GuardRail driver/amp protection, precision crossover action, Digital Extension and Excursion Processing (DEEP) LF transient control, and complex FIR and IIR filters with time/frequency/amplitude optimization.

I tested a system with two K10s and the KSub. The K10 has a flexible input panel. It can mix two input sources (one switchable XLR combo mic/line input and a line input with combo XLR plus RCA jacks) via two recessed gain pots, and it has a post-gain line out for feeding the KSub or a second K10. Silkscreened arrows on the panel that explain this are somewhat confusing. It all became clear a couple of minutes later. Most users will never use the onboard mix functions anyway, although they’re nice to have, just in case.

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I first used the two K10s alone (no sub) for vocal reinforcement for a band in a medium-sized room. Volume-wise, the K10s had no problem keeping up. I was surprised by the output of these little (20.4”x12.6”x11.8”), 32lb. 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 loudspeakers from rotating on the pole mount, but a little duct tape on the pole took care of that.

Next I checked 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 was 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 26”x14”x28”, 74lb. enclosure.

Overall, the K system is a winner. The top boxes can easily handle smaller events alone, or you can bring in a sub (or subs) for larger shows. Setup is fast, and the axisymmetric waveguides make them ideal for doing double duty as stage wedges. Fly points and rear Euroblock connectors for remote gain control are nice touches for permanent installs. Thumbs up on this system.

Product Summary

  • Company: QSC
  • Product: K Series
  • Pros: Lightweight, compact, fast setup, natural sound, smooth coverage.
  • Cons: Confusing input panel, no lock screw on pole mount socket.
  • Applications: Sound reinforcement.
  • Price: $759 (K8); $899 (K10); $999 (K12); $1,200 (KSub)


  • Response (-6dB): K10, 56Hz-18kHz; KSub, 48Hz-134Hz
  • Max SPL: K10, 129dB; KSub, 130dB
  • Inputs: Combo XLR, RCA
  • Output: XLR
  • Dimensions: K10, 20.4”x12.6”x11.8”; KSub, 26”x14”x28”

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