Sunday, October 26, 2008

Audio Consoles

Consoles (also known as boards or mixers) take input signals and amplify, balance, process, combine and route them for broadcasting or recording. Some consoles also store operational data.

There are a few broad categories of consoles: analog or digital, on-air broadcast or production/post-production, and software based virtual consoles.

Analog consoles use physical electric circuits and wiring to control that audio signals flow throughout the board.

The patch bay is used for flexibility in the signal flow. Jacks are wired to console components to allow for re-routing of signals both within the console as well as with other equipment outside of the board, such as an external Equalizer or Compressor unit. Patch cords are the cables used to plug into the jacks to direct signal flow.

Digital consoles convert the analog signal to digital at the input. Routing is done on board as well as through patching cords.

Virtual consoles use a simulated console on a computer screen with specialized software.

On-air broadcast consoles handle audio sources that are immediately available to an audience, along with pre-packaged audio for playback. It has more control for rapid transitions between the DJ, music, advertisements, guests, call-ins, and others.

Inputs bring the signals from the microphone, CD player, recorder, phone calls, etc. into the console. Faders control the loudness of each channel.

The master fader handles the combined signals feeding to it from the input channels and then outputs the combined final signal.

Features found on most consoles include the input/output channel strips, input selector (high versus low level signal), phantom power (48 V), mic pre amp (boosts weak mic signal to a voltage of useable level to minimize noise introduced by console), trim/gain (changes input sensitivites- boosts low level or prevents overload in high levels), pad (lowers power of signal when trim isn't enough), channel assignment and routing, pan pot (panoramic potentiometer - shifts proportion of sound to any point between L and R), EQ and filtering (alters signal's frequency response by raising or lowering level of a range of freencies or attenuating freq at certain levels), signal procession, FX sends to external signal processing, and Solo/Mute buttons.

There are also VU (Volume Unit) meters that indicate the loudness level based on a perceived volume, reading the average of the combined waveforms. Includes the percent of modulation in relation to the maximum of the system's ability as well as the dB level. Peak Meters are electronic instead using LEDs but have the same purpose as the VU.

Automation is used to store mixer settings for recall, in order to compare mix settings of a recording to one another. Write - creates automated mix where data is monitored and stored. Read - plays back automation data. Update - makes changes to automation.

Balanced cables are used because they resist electrical interference and therefore result in lower noise.

Digital consoles do not have an physical connections or circuits, all functions go through the central processor. This removes duplication of many channels, and increases the number of operations that can be done in a smaller area.

Digital Control Surfaces are similar to consoles but there are no audio signals in them, only control circuits that send digital instructions to other units for signal processing. These are used with Digital Audio Workstations (DAWs) like Pro Tools.

Helpful Links:
Cable information (XLR, TRS, etc)

1 comment:

Zentranox said...

Thank You for that info..very helpful.