Mackie FR800/FR1400/FR2500 FR Series Owner's Manual - Page 9

Owner's Manual Rear Panel Features 6. XLR INPUTS 9. CLIP LIMIT These inputs allow you to connect balanced XLR plugs. These are wired conventionally, with pin 2 hot, pin 3 cold and pin 1 ground. When engaged, the CLIP LIMIT switch protects your loudspeakers from the effects of clipping. It is designed to be virtually transparent, meaning you probably won't even notice any audible difference when the switch is turned on. 7. 1/4" INPUTS These inputs allow you to connect balanced 1/4" TRS or unbalanced TS plugs from line-level sources. We recommend that you leave this switch on at all times. However, if you are working at quiet levels, or you have already placed a compressor/limiter in the signal path, you can leave the CLIP LIMIT switch off. Use balanced connections where possible, as these offer better rejection of noise than unbalanced lines. Use high-quality, three-conductor shielded cable for balanced connections. The better the shield, the better the audio signal is protected from induced EMI and RFI. 8. SUBSONIC FILTER Turn this switch on to engage a low-frequency cutoff (high-pass) filter at 30 Hz. The frequency range below 30 Hz is attenuated. The amplifiers can amplify signals below 20 Hz, but most speakers can't reproduce frequencies that low. By engaging the SUBSONIC FILTER, you allow the amplifier to power only the frequencies you can hear. In addition, this filter can reduce low-frequency stage noise (footsteps) and accidental microphone pops that could damage a loudspeaker. Leave this off if you are powering a subwoofer, or if your speakers can reproduce low frequencies such as the kick drum range. 10. AMP MODE This switch determines the input signal routing within the amplifier. For most applications, you will use the STEREO setting. However, some applications might be better suited for using either the MONO or the BRIDGE setting. STEREO: This is the normal position used when amplifying stereo signals. This mode accepts separate left and right inputs (1 and 2), and routes them to the CHANNEL 1 and CHANNEL 2 outputs. Each channel's Level control adjusts the gain for its own channel, and each channel is independent. MONO: This mode is used when you want to send a mono signal to both outputs. It accepts a single input (INPUT 1), and routes it to both the CHANNEL 1 and CHANNEL 2 outputs. Each channel's Level control adjusts the gain for its own channel. BRIDGE: This mode accepts a single input (INPUT 1), and uses both amplifier outputs to double the power to one speaker. Use the Channel 1 Level control to adjust the gain (turn the Channel 2 Level control all the way down). The hookup diagrams show how to connect a speaker in Bridge mode. 6 78 9 10 Owner's Manual