Live Design Blog Archive


KGroupStack Powered, portable systems pack 1,000 watts of Class D amplification

COSTA MESA, CA, April 1, 2009—With the launch today of its new K Series product group, QSC has redefined the standard in compact, lightweight, high-performance powered loudspeakers.

The combination of a professional-looking molded ABS enclosure, uniformly matched drivers, advanced DSP, and QSC's legendary touring spec amplification has resulted in an unprecedented package. K Series is demonstrably able to outperform other molded enclosure systems due in part to one fundamental principle: the same 1,000-watt Class D amplifier module powers all four models — whether the K8, K10, K12 — or KSub (dual-12” subwoofer).

QSC Director of Entertainer Solutions Ray van Straten states, “The K Series has been designed entirely without compromise, from the ground up. QSC has departed from convention and at the same time exploded a myth that smaller woofers must equate to lower performance.

“Competitors will typically use the highest power amplifier and the best quality drivers in the largest format model, while designing their smaller format models with lower power amplification and lesser performing components. This allows them to reduce the price of the smaller models, further propagating the myth that a smaller woofer enclosure necessitates lower performance.”

He continues, “Apart from using the same amp module across the line, we are also using the same quality woofer motor in all four models, and the same 1.75” HF device in the three 2-way enclosures. The primary differentiator is the resulting output dispersion — the K8 being the widest at 105° and the K12 the narrowest at 75°. The choice for the customer then is not ‘good, better, best', but ‘best, best, best' — and ‘How wide a box do I need?'”

This radical approach is achievable due to a process called Directivity Matched Transition DMTâ„¢. DMT allows QSC to take advantage of a fundamental law of acoustics — smaller diameter woofers have wider coverage patterns than larger ones. QSC has simply matched the HF device to the LF dispersion, allowing for the smoothest and flattest frequency response possible across the entire sound field.

Add to this advanced DSP processing and an enclosure molded from ABS — a material far more rugged and sonically pleasing than conventional plastics — and the K Series delivers a completely new standard of performance in this category of loudspeakers.

Several proprietary QSC DSP technologies are incorporated into the K Series. One such technology is Digital Extension and Excursion Processing (DEEPâ„¢). DEEP allows each of the K Series models to deliver levels of low-frequency extension, hitherto impossible in enclosures of this size. Intrinsic Correctionâ„¢, first featured in QSC line-array technology, utilizes dozens of spatially-averaged measurements, mapped to the processor to deliver smooth and accurate reproduction across the entire sound field.

Preventing amplifier clipping or overload is QSC's proprietary GuardRailâ„¢ technology, also present in their popular GX amplifier line. GuardRailâ„¢ closely monitors the input voltage and controls the amplifier output stage before the onset of clipping. Unlike typical clip limiters, when GuardRail is activated, the results are all but undetectable – there's none of the typical ‘pumping' associated with other methods. In addition, user EQ controls are provided to select between application settings (EXTSUB, VOCAL, or FLAT response).

K Series boasts other user-friendly features. For example, when speakers are pole-mounted, the Tilt-Directâ„¢ pole socket converts to a 7.5° down-tilt with a simple 180° rotation of the dial. A locking IEC power cord is included, preventing accidental disconnect during a performance. For installed applications, connecting a commonly available potentiometer to the unit allows the operator to obtain gain control from a remote location. Multiple K Series units can also be daisy-chained together to one centralized control. Additionally, the K Series enters standby mode after five minutes of inactivity, both conserving power and enhancing ease of use.

The entire package is housed in rugged and sonically-friendly ABS (the sub in birch plywood) with steel grilles (2-way models) and carry-friendly ergonomic aluminum handles. The KSub also features low-noise casters for easy transport.

The Products

Three two-way models are available, with 8”, 10” and 12” woofer diameters, built around an advanced switch-mode power supply and Class D output section, the subwoofer power module also delivering 1,000 watts from an efficient and lightweight design.


The K12 is a 12” two-way system with 75° horizontal and vertical coverage. Low frequencies extend to 48 Hz (-10 dB high acoustic output, 131 dB peak). This low-frequency extension makes the K12 the ideal choice for music playback and live reinforcement of instruments, especially in venues where a more directional speaker is needed. Equally at home in the stage monitor role, the K12 enclosure has an angled side for use as a low-profile, horizontal wedge and a flat side for proper side-fill use.


The K10 is unlike other 10” powered loudspeaker systems, sharing the same amplification, HF device and low-frequency driver of the same high quality as its big brother, and offering 90° (conical) coverage and 129 dB peak output (low frequencies extending to 56 Hz. The K10 offers unprecedented power and performance from an extremely compact system, which can also be used as an ultra low-profile, horizontal wedge or sidefill.


The extremely compact size of this 8” powered loudspeaker won't intrude on

audience sightlines. Its 105° wide dispersion is a major advantage when the audience is up close to the loudspeaker. Low frequencies extend to 61 Hz (-10 dB) and the unit outputs an amazing 127 dB.


For live reinforcement of bass instruments and drums, or higher level playback of recorded music, the KSub is the ideal supplement to the K Series two-way models — an M20 threaded pole socket (pole included) provides a secure, wobble-free method of elevating a mid-high speaker over the subwoofer. The compact footprint won't take over the stage, dance floor or seating area of smaller venues. A pair of high-power 12” speakers in an optimized bandpass enclosure will handle everything the 1,000 watt power module can give them. Compact in size, and ergonomically designed, thoughtfully placed handles, noise-free casters along with an available accessory cover ease load-in and load-out.

Processing, Connectivity & Monitoring

While the DSP functions are optimized using Intrinsic Correction™, DEEP™, DMT™ and GuardRail™ technologies (with the high-pass filter included for use with subwoofer systems), two XLR-combo inputs, each with its own level control, are also provided. Both accommodate line-level inputs and one may be switched to microphone level sensitivity. Phono (RCA) input jacks are also included for connection of consumer electronics sources (2-way models only). Dual XLR outputs are provided for dual ‘loop-thru' XLR/M connectors and a single XLR jack is available as a summed output. All three input sources may be utilized at once and mixed via the two gain control knobs (2-way boxes only).

Input Panel LED indicators are provided for power, signal present, mic level sensitivity and limit annunciation. A front-mounted power LED may be disabled by means of a rear panel switch when desired, or set so it indicates when the limit circuitry has been engaged.


Each K model incorporates a conical waveguide that maintains pattern control all

the way down to the crossover frequency. The coverage angles of the

waveguides are tailored for a smooth transition from woofer to compression driver with far less ‘waist-banding' or other directivity related anomalies than other products in this class.

Suspension and Mounting

The K Series two-way models may be pole-mounted, suspended or yoke mounted. The K8, K10 and K12 yoke accessory kits allow for either horizontal or vertical yoke mounting, providing a flexible means of attaching K Series loudspeakers to a building structure or truss. When suspended deployment is required, M10 threaded inserts support vertical or horizontal suspension, while the integral pole mount socket accommodates 35mm speaker poles for use on a speaker stand or over a sub. The pole socket is designed so that the speaker may be angled down 7.5° in order to cover the audience while keeping acoustic energy off reflective walls and ceilings.

Accompanied by a complete range of accessories, padded carrying bags and various mounting accessories, K Series products provide a consummate package for the AV rental, installation, MI and DJ markets.

Principle Product Features

° 1,000 watt, efficient and lightweight class-D power module

° Lightweight (27 lbs. - 41 lbs. 2-way, 74 lbs. KSub)

° Professional appearance and rugged construction

° Directivity Matched Transition (DMTâ„¢) and Intrinsic Correctionâ„¢ DSP tuning for accurate, undistorted performance across the entire sound field

° GuardRailâ„¢ technology discreetly protects the system from damaging overload

° DEEPâ„¢ mode for enhanced low-frequency extension without a subwoofer

° Locking IEC power cable

° XLR and 1/4” connectors

° Phone mic/line and line inputs with loop-thru connectors and independent level controls.

° Phono (RCA) inputs (2-way units)

° Three 2-way models – each with coverage pattern optimized to match the LF driver

° Front-mounted LED may be switched off or to indicate ‘LIMIT' or AC Power On

° Dual angle, 35 mm pole socket with Tilt-Directâ„¢ allows the speaker to be angled down to put the energy on the audience instead of the back wall

° Suspension and yoke mounting accessories available

° 4” voice-coil woofer design for high output

° 1.75” voice-coil compression driver

° High Pass Filter for use with subwoofers

° Subwoofer 1,000 watt, efficient and light-weight Class D power module

° Dual 12" band-pass for compact size, efficiency and high-power handling

° Threaded pole socket for solid, secure pole mounting

° 3" Casters

The K Series will be shipping nationwide in mid-May.

QSC Audio Products, Inc. is a leading manufacturer of power amplifiers, loudspeakers, signal processing, digital signal transport, and computer control systems for professional audio markets worldwide. For more information, contact QSC Audio Products, Inc., 1675 MacArthur Blvd., Costa Mesa, CA 92626 USA. Phone: 800-854-4079 (USA only) or 714-754-6175. Fax: 714-754-6174. E-mail: [email protected], or visit


Gregory A. DeTogne

Gregory A. DeTogne Public Relations


[email protected]

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