Live sound reproduction
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A live sound reproduction system has two main forms:
A "sound reinforcement" system enhances the volume of the initial sound and will be designed so that as much as possible the listener will not realise that an artificial system is being used to make it easier for them to hear the initial sound. Such systems are typically deployed in Churches, meeting rooms and smaller conference venues.
A "public address" (PA) system is a usually simpler design that just amplifies the initial sound and it will be obvious to the user that it is being used. PA systems require a microphone, an amplifier of some kind and a loudspeaker and can range in size and complexity between handheld (megaphone) or requiring several large trucks to move.
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[edit] PA Systems
A basic band setup is detailed in the image below:
Here we have a typical setup consisting of a Front Of House (FOH) mixing desk, connected via a Multicore to the stagebox on stage. Returns on the stage box allow the outputs from the mixing desk (Program Left, Right, Centre (MONO)and Foldback channels or monitor sends) to be connected to the amplifier rack, containing the Amps, and perhaps an active crossover network. The amps in turn are then connected to the Speaker stacks. Depending on the system used, there may be several cabinets per side, varying from Sub (20Hz-100Hz) Bass (80Hz-350Hz) Mid (300Hz-4kHz) and Top (3kHz-20kHz).
Microphones, DI Box and balanced Line Level signals can be connected to the stagebox to feed the input channels on the mixing desk via the multicore.
[edit] Front Of House
At the Front of House (FOH) position there is a mixing desk and a 19" Rack containing various outboard equipment, performing equalisation, dynamic processing, effects and 2 track playback (Usually CD or MiniDisc).
[edit] Monitors
Monitors are usually wedge shaped speakers placed in front of the musicians / artist on the stage, or stacks of speakers on both sides of the stage called "side fills". There is usually another stack of speakers for the drummer, called the "drum fill" or "drum mix". They can be fed with a signal either from the FOH position, or from an on stage monitor desk. The monitor desk can direct any microphone or other channel plugged into the "main splitter" to "mixes" or stage positions around the stage. A concert with a full band will typically have 6 to 12 mixes or sets of speakers, so the performers can hear themselves and each other during the performance. The onstage performers tell the "monitor engineer" or "monitor mixer" what instrument levels he or she wants in their mix. Increasingly, more people are opting for wireless "In Ear" monitors.
