SIG Signal Indicator LED | QSC Audio MD-FP122/64r, MD-FP122/94r

SIG (Signal) Indicator LED

The green SIG (signal) indicator alerts the user to the presence of an input signal to the MD loudspeaker.

Normal Indication

The green SIG indicator illuminates when the input signal exceeds -25 dB.

If No Indication

Check Gain settings and increase gain if necessary. Check input connections and audio source for signal. If the red LIM LED illuminates, refer to the LIM indicator section, below.

Abnormal Indication

If the green SIG LED illuminates with no signal input, there may be system oscillations or some other malfunction. Disconnect the input or fully reduce the gain. If the green SIG LED remains on, the amp may need servicing.

LIM (Limiter) Indicator LED

The red LIM indicator alerts the user to several abnormal conditions within the MD loud- speaker:

Continuous Bright Red Light

•Indicates protective mute mode.

•The speaker normally passes through muting for several seconds after applying power, after which the light should go out, and sound should be heard.

•If the speaker enters Mute during operation, it has either overheated or developed a fault.

•Overheating should correct itself within 1-2 minutes, after which sound should resume. See below for a full explanation of thermal protection.

•Short periods of muting indicate a component fault. In this case AC power should be removed and the speaker serviced.

Momentary Bright Red Flashes

•During operation, bright flashing indicates clipping (overdrive distortion).

•This is normally due to excessive volume, and will likely be accompanied by audible distortion.

•If the speaker mutes repeatedly during peaks, there may be a component fault. AC power should be removed and the speaker serviced.

Continuous Half-bright Light

•Indicates that the internal limiter is reducing gain, due to prolonged clipping and/or excessive temperature.

•After several seconds of severe clipping, the limiter will reduce power to protect the speaker and improve the sound. This results in a steady, half-bright red indication. Any further clipping will still result in bright flashes on top of the steady half-bright indication. When the program level is reduced, the limiter will clear after several seconds, and the red indicator will go out.

•If the power module overheats, the first response is to trigger limiting, to reduce volume and limit further temperature rise. This results in a steady half-bright illumination that does not clear even after reducing program level. It may take several minutes for temperature to drop and clear the limiter. During this time, the exposed heat sink will feel uncomfortably hot to the touch. If overheating continues, the amplifier will ultimately mute, resulting in a full-bright red indication. When muting clears, the amplifier will resume operation, with thermal limiting still active until it further cools off.

•Overheating is usually caused by excessive ambient temperature, since the internal temperature rise of the Class-D power module is relatively low. Protect the speaker from excessive tempera- tures, such as being placed over a heater vent, or allowing direct sunlight to impinge upon the heat sink surface.

LIM (limiter) indicator LED

SIG (signal) indicator LED

MD-FP122/64r, MD-FP122/94r specifications

QSC Audio has long been recognized for its commitment to delivering innovative audio solutions tailored for professional applications. Among its standout offerings are the MD-FP122/94r and MD-FP122/64r loudspeakers, both of which are designed to meet the rigorous demands of live sound reinforcement and installation projects.

At the core of these models is their exceptional acoustic design. The MD-FP122/94r features a 12-inch low-frequency driver complemented by a 1.75-inch high-frequency compression driver mounted on a unique waveguide. This configuration allows the speaker to deliver impressive clarity, depth, and coverage, making it highly effective for both live performances and permanent installations. The MD-FP122/64r, while sharing a similar foundation, is optimized for different applications, featuring a 64-degree dispersion pattern that enhances audience coverage within various venue sizes.

Both models utilize advanced materials in their construction, ensuring durability without compromising audio quality. The enclosures are built using high-density plywood that minimizes unwanted resonance and vibration, resulting in clearer sound reproduction. Additionally, both speakers come equipped with a robust, weather-resistant finish, allowing them to withstand the rigors of outdoor environments.

The MD-FP series also supports QSC’s proprietary technology, including their PowerWave™ design. This sophisticated approach maximizes the efficiency of the low-frequency driver, providing enhanced power handling and extending overall performance. Dynamic range is also optimized, allowing users to experience a full spectrum of audio, from the softest whispers to the most thunderous bass.

The integration of user-friendly features further enhances the versatility of the MD-FP122/94r and MD-FP122/64r. These speakers include multiple mounting options to accommodate various installation scenarios, making them suitable for both portable and fixed applications. Additionally, the models are designed to work seamlessly with QSC's Digital Signal Processors (DSP), allowing for tailored tuning to meet specific acoustic needs and ensuring optimal performance across different settings.

In summary, QSC Audio's MD-FP122/94r and MD-FP122/64r loudspeakers exemplify high-quality design and innovative technology. With their powerful performance, durable construction, and versatile application possibilities, these models represent an excellent choice for audio professionals seeking reliable and high-fidelity sound reinforcement. Whether for touring events or permanent installations, they provide the level of performance required to elevate any audio experience.