User manual RANE MC 22

[. . . ] OPERATORS MANUAL MC 22 STEREO COMPRESSOR QUICK START Shredded, this document makes excellent packing material. If you run out of patience quickly, at least read this part to make sure you don't exterminate everything within a two mile radius by doing something wrong. Attach one or two channels of inputs and outputs to the respective connectors on the rear. Do not connect the XLR "+" or "­" output pins to ground, as this may cause the power supply to shut down. [. . . ] String pops on a bass are one example, shrill peaks on a flute are yet another. The higher tones require more breath and can seem much louder than lower pitches. LONG DISTANCE LINE DRIVER The MC 22 is excellent as a line level amp for driving long lines (from the mixer to the stage for instance). With the COMPRESSOR switch in the BYPASS position, the INPUT LEVEL control and the output amplifiers remain in the circuit. Balanced XLR connections are recommended for the long run from the MC 22's outputs. A balanced piece of equipment (equalizer or amplifier) must be used at the receiving end of this long line. For unbalanced systems, use the ¼" inputs on the MC 22 and use the balanced XLR outputs to run the long distance. See the SOUND SYSTEM INTERCONNECTION section for proper cable wiring. Figure 3. Vertical axis = output level, horizontal axis = input level. Manual-5 SOUND SYSTEM WITH COMPRESSION Let's run a stereo system with compression (see Figure 1 on the next page). For this example, we use a Rane Mojo MX 22 2-Way Crossover and a Mojo MQ 302 Stereo Equalizer along with the MC 22 Stereo Compressor. Patch the MC 22 Compressor Inputs from the program source or mixer outputs, and send the MC 22 Outputs to the system equalizer (if you have one), and then on to the crossover inputs (if you have one). Set the LINK switch to ON, and adjust the THRESHOLD and RATIO controls to keep the entire system dynamic range under control. However, this document contains suggestions for external wiring changes that should ideally only be implemented by trained technical personnel. Safety regulations require that all original grounding means provided from the factory be left intact for safe operation. No guarantee of responsibility for incidental or consequential damages can be provided. (In other words, don't modify cables, or try your own version of grounding unless you really understand exactly what type of output and input you have to connect. ) THE ABSOLUTE BEST RIGHT WAY TO DO IT Use balanced lines and tie the cable shield to the metal chassis (right where it enters the chassis) at both ends of the cable. A balanced line requires three separate conductors, two of which are signal (+ and ­) and one shield. The shield serves to guard the sensitive audio lines from interference. Only by using balanced line interconnects can you guarantee (yes, guarantee) hum-free results. Chassis tying the shield at each end also guarantees the best possible protection from RFI [radio frequency interference] and other noises [neon signs, lighting dimmers]. THE NEXT BEST RIGHT WAY TO DO IT The quickest, quietest and most foolproof method to connect balanced and unbalanced is to transformer isolate all unbalanced connections. The goal of transformer adaptors is to allow the use of standard cables. [. . . ] For example, a nominal +4 dBu system that clips at +20 dBu has 16 dB of headroom. hum Unwanted sound contaminating audio paths due to EMI (electro-magnetic interference) caused by AC power-lines & transformers getting into unbalanced, poorly shielded, or improperly grounded connecting cables. Hum has a definite smooth (sine wave) repetitive sound based on the harmonics of 50/60 Hz such as 100/ 120 Hz and 150/180 Hz. If a graphic equalizer's adjacent bands, when moved together, produce a smooth response without a dip in the center, they are interpolating between the fixed center frequencies. [. . . ]