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Sound Mixers

Mixer Selection

A mixing console, or audio mixer, also called a sound board or soundboard, is an electronic device for combining (also called "mixing"), routing, and changing the level, timbre and/or dynamics of audio signals. The mixer outputs modified signals that are summed to produce the combined output signals.

A mixing console is an important part of the church sound system. An example of a simple application would be to enable the signals that originated from two separate microphones to be heard through one set of speakers at the same time. When used for live performances, the signal produced by the mixer will usually be sent to the amplifier. If the mixer is “powered” or it is being connected to powered speakers.

Structure

The audio mixing console in a 'live' mixing application has an input strip that is usually separated into these sections that repeat for each channel of audio:
  • Input Jacks / Microphone preamps
  • Basic input controls
  • Channel EQ (High, Mid high,Mid and low)
  • Routing Section including Direct Outs, Aux-sends, Panning control and Subgroup assignments
  • Input Faders
  • Subgroup faders
  • Output controls including Master level controls, EQ and/or Matrix routing

Basic input controls

Below each input, there are usually a group of rotary controls (knobs, pots). The first is typically a trim or gain control. The inputs buffer the signal from the external device and this controls the amount of amplification or attenuation needed to bring the signal to a acceptable level for processing. The signal control per channel is modified with a slider or fader control.

Hardware routing and patching

For convenience, some mixing consoles include inserts or a patch bay or patch panel. Most, but not all, audio mixers can:
  • Add external effects
  • Use monaural signals to produce stereo sound by adjusting the position of each signal on the sound stage (pan and balance controls)
  • Provide phantom power (typically 48 volts) required by some microphones
  • Create an audible tone via an oscillator, usually at 440 Hz, 1 kHz, or 2 kHz.
Some mixers can:
  • Add effects internally.
  • Interface with computers or other recording equipment (to control the mixer with computer presets, for instance)
  • Be powered by batteries.

Digital vs. Analog

Digital mixing console sales have increased dramatically since their introduction in the 1990s. Digital mixers are more versatile than analog ones and offer many new features, such as the ability to save multiple mute groups, multiple VCA groups and channel settings into a scene and reconfigure signal routing at the touch of a button.

One of the most important value of a digital mixer in the church enviroment is its ability to save all the settings in memory and recall them at a push of a button. If the church has a traditional choir at one service and a contempory choir at the next the mixer settings will be completely different. In less than 5 minutes the mixer can be set up for either choir group with mixer settings that have been perfected over months or by professionals and saved.

The faders can be "swapped" or "flipped" to show aux send levels; a feature very useful in mixing artists' monitors. In addition, digital consoles often include a range of special effects such as parametric EQ, compression, gating, reverb, automatic feedback reduction, tap delay and straight delay. Some products are expandable via third-party software features (called plugins) that add further reverb, compression, delay and tone-shaping tools. Several digital mixers include spectrograph and real time analyzer functions. A few incorporate loudspeaker management tools such as crossover filtering and limiting.

Digital mixers can be designed to be quieter than most analog mixers, as digital mixers often incorporate very low threshold noise gates to stop inactive mix bus background hiss from summing with active signals. Digital circuitry is more resistant to outside interference from radio transmitters such as walkie-talkies and cell phones.

Recommended Mixer Manufacturers

Digital Mixers
  • Yamaha
Analog Mixers
  • Allen and Heath
  • Mackie
  • Soundcraft
  • Yamaha
  • Tascam