THE RIGHT POWER
There’s a QSC GXD amplifier within 1dB of the ideal power for your speaker system. Best practice is to use an amplifier capable of delivering approximately twice the loudspeaker’s rated power capacity. Too little amplifier and the speakers won’t deliver everything they’re capable of and the risk of destructive amplifier clipping is increased. Too much power probably means unnecessary amplifier expense.
To determine the power points for the QSC GXD Amplifier series, QSC examined the loudspeakers most widely used for sound reinforcement by musicians, DJs and production professionals. Overall, these speakers are equipped with woofers that fall into a couple of categories of continuous power capacity - low-power drivers that can handle 150 - 250 watts, and mid to high-power drivers rated around 250-400 watts. Single woofer loudspeaker systems using these drivers will typically have an impedance of 8Ω. Dual woofer loudspeakers will, of course, have power ratings that are two times that of the single woofer model and an impedance that is half that of single-woofer models.
DIGITAL SIGNAL PROCESSING
The QSC GXD amplifiers are unlike other amps in this category that provide little more than a front panel screen to control the same functions that have been under rear-panel, DIP switch control for decades. The QSC GXD amps bring full-function loudspeaker processing capability to a new price point with all the processing necessary to get the most from a loudspeaker system. The DSP section includes High and Low-Pass filters (24dB LR), 4-band parametric equalizer, signal alignment delay, and RMS/Peak speaker protection limiting. Twenty presets for selected typical systems are provided as generic “starting points” are included.
The most common cause of loudspeaker failure is amplifier clipping. The digital limiter used in the QSC GXD amplifiers is set to prevent the amplifier from being driven into clipping while delivering the maximum usable output. In addition to amplifier limiting it also provides smart speaker protection by simply setting the loudspeaker’s continuous power and impedance (4Ω and 8Ω), and selecting whether Mild, Medium or Agressive protection is desired.