Using Your MPM Console, Microphone Placement

USING YOUR MPM CONSOLE

The final output from your sound system can only ever be as good as the weakest link in the chain, and especially important is the quality of the source signal because this is the starting point of the chain. Just as you need to become familiar with the control functions of your mixer, so you must recognise the importance of correct choice of inputs, microphone placement and input channel settings. However, no amount of careful setting up can take account of the spontaneity and unpredictability of live performance. The mixer must be set up to provide “spare” control range to compensate for changing microphone position and the absorp- tion effect of a large audience (different acoustic characteristics from soundcheck to show).

MICROPHONE PLACEMENT

Careful microphone placement and the choice of a suitable type of mi- crophone for the job is one of the essentials of successful sound rein- forcement. The diagrams on the left show the different pick-up patterns for the most common types of microphone. Cardioid microphones are most sensitive to sound coming from in front, and hypercardioid micro- phones offer even greater directivity, with a small amount of pickup be- hind the microphone. These types are ideal for recording vocalists or instruments, where rejection of unwanted sounds and elimination of feed- back is important. The aim should be to place the microphone as close as physically possible to the source, to cut out unwanted surrounding sounds, allow a lower gain setting on the mixer and avoid feedback. Also a well chosen and well placed microphone should not need any appre- ciable equalisation.

There are no exact rules - let your ears be the judge. In the end, the position that gives the desired effect is the correct position!

INITIAL SETUP

Once you have connected up your system (see the sections on connec- tion and wiring earlier in this manual for guidance) you are ready to set initial positions for the controls on your mixer.

Set up individual input channel as follows:

•Connect your sources (microphone, keyboard etc.) to the required inputs.

WARNING: Phantom powered mics should be connected before the +48V is switched on. Ensure the PA system is OFF when switch- ing phantom power on or off.

•Set Master faders at 0, input faders at 0, and set power amplifier levels to about 70%.

•Provide a typical performance level signal and press the PFL but- ton on the first channel, monitoring the level on the bargraph me- ters.

•Adjust the input gain until the meter display is in the amber sec- tion, with occasional peaks to the first red LED at a typical maxi- mum source level. This allows sufficient headroom to accommo- date peaks and establishes the maximum level for normal opera- tion (but see note below).