Strother Bullins on QSC Audio K Series Loudspeakers

9/20/2016 11:19 AM Eastern

After having reviewed numerous portable PA (PPA) enclosures over the years—most of which have been powered, two-way full-range speakers with at least a couple of input types available per cabinet—I thought it was due time to revisit QSC Audio’s impressive K Series; I requested a pair each of its three-model, full-range line-up. Though many newer competing models are on the market today, the K Series’ offerings—the K8, K10 and K12 featuring one 1.75-inch high-frequency driver and 8-, 10-, and 12-inch low frequency drivers, respectively—remain top contenders in an increasingly crowded powered PPA marketplace. Why? The series’ proprietary features and notably pro-grade build quality make it an overachieving live sound reinforcement bargain.

One of the earliest Class D-equipped portable PA lines delivering a truly impressive amount of power, QSC’s K Series—“K” for kilowatt—offers dual 500 W amplifiers; its high-frequency and low frequency dual amps both draw their current and voltage from a single switch-mode Class D, high output/low heat power supply that adds a mere 6 lbs. to the total K Series package. As such, the cabinets are more rigidly built with tour-quality handles, grilles, fittings and such yet are still reasonable in weight; the K8, K10 and K12 weight in at 27, 32, and 41 lbs., respectively. A light, comparably scratch-resistant surface made of a high-impact, low-vibration synthetic material is used for the K Series’ cabinet materials. The integral pole mount cup per cabinet, providing one of many QSC proprietary features called Tilt-Direct, offers a 7.5-degree angle tilt, and is also notably well designed and built. For permanent/semi-permanent install, the K Series provides a number of fly points per cabinet.

The K Series’ sound dispersion design—called DMT, or Directivity Matched Transition—varies per model; this matches each cabinet’s waveguide to the same coverage as the woofer for that box at the crossover frequency (2 kHz), which, by design, gives the K Series a smooth response in the frequencies around 2 kHz over the coverage area. Nominal coverages for the K8, K10 and K12 are 105, 90 and 75 degrees conical, respectively.

Also of note is the K Series’ EQ options, all of which work well in most appropriate settings: Vocal Boost for an attractive mid-frequency lift (great when the cabinets are primarily used for vocal-only reinforcement applications), and QSC’s trademarked DEEP curves providing tasteful low frequency extension. An “EXT SUB” setting is also provided for K Series use with a subwoofer, either the series’ own dual 12-inch driver-equipped KSub (also featuring 1000W of Class D power) or a third-party sub.

I/O is sufficient, if not extensive: dual balanced combo XLR/TRS inputs, with channel one switchable mic/line; dual RCA inputs; and a post-gain mix XLR line out. The rear panel is uniquely laid out but quite intuitive, featuring solid-feeling switches and knobs as I’ve come to expect from any product I’ve had the opportunity to use from QSC.

Overall, how does a K Series portable PA rig sound? It’s musical, comparably full, rich and widely flexible across a range of stylistic inputs—impressive considering its general lack of user-adjustable parameters, such as even fixed frequency gain/boost, etc. The K Series’ intrinsic sound qualities are perhaps due to the series’ aptly named Intrinsic Correction DSP; if so, as an end user, that’s fine with me if I don’t exactly know what’s going on inside the cabinet. Considering what the K Series offers in fidelity and build quality, its price points are bargains, as I’m confident the K Series will provide owners with years of regular, superb-sounding use.


PROS: Musical, well voiced sound; notable proprietary features and semi-fixed parameters; impressive build quality and components.
CONS: Lack of variable frequency adjustments
PRICE (STREET): $649, $699, $799, $1,079 (K8, K10, K12, KSub, respectively)


FREQUENCY RANGE: 61 Hz-20 kHz, 56 Hz-20 kHz, 48 Hz-20 kHz (K8, K10, K12, respectively)
OUTPUT (PEAK SPL @ 1M): 127 dB, 129 dB, 131 dB (K8, K10, K12, respectively)
AMPLIFIER POWER (PER ENCLOSURE): 1000 W continuous Class D
LF DRIVER INFORMATION: LF: 8” cone transducer, 10” cone transducer, 12” cone transducer (K8, K10, K12, respectively)
INPUTS: Balanced combo XLR-1/4” mic/line, balanced combo XLR-1/4” line, 2 x RCA (phono)
NET WEIGHT: 27 lbs., 32 lbs., 41 lbs. (K8, K10, K12, respectively)

Strother Bullins is Technology Editor for NewBay Media’s AV/Pro Audio Group.

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