The Audio mixing console
Introduction
Sound optimization is the goal of any sound engineer and this sound is optimized using stereo mixing console (audio mixer).
a mixing console is an electronic device which combines sounds of different audio signals. Inputs to the console include microphones which is used by singers and for picking up acoustic instruments, signals from electric or electronic instruments, or recorded music.
image credit |lumenfoundry.com
A basic analog audio mixer combines several incoming signals into a single output signal.Mixing consoles are used in recording studios , public address systems , sound reinforcement systems, nightclubs, broadcasting and television.
In practice, mixers do more than simply mix signals. They can provide phantom power for condenser microphones ; pan control , which changes a sound's apparent position in the stereo soundfield; filtering and equalization , which enables sound engineers to boost or cut selected frequencies to improve the sound.
Components of Analog mixing console
Input section
Input gain control (rotary fader type) is the first section in signal flow which is commonly known as Pre – Amp (pre-amplification). This control adjusts the level or degree of amplification provided by the input amplifier and is labeled in decibels (dB) either increasing or decreasing steps. Inputs that vary continuously are normally switchable between Microphone and line position, depending upon the output level of the microphone or ‘line’ input as per requirement. For a ‘microphone’, high amplification is required as the microphone input is low and for ‘line’ inputs, little amplification is required and the gain control normally provides adjustment either side of unity gain ( 0 dB ) perhaps ( ±20dB ). Input gain control is used to control the input level.
image credit | www.mediacollege.com
Equalization
This section have controls for two frequency bands (in the case of the figure provided), the high and the low frequency. Equalizer boost and cut of around ±12 db over low and high frequency bands is available. Equalizer is used to control the tone of the signal through boosting and cutting of the high and low frequencies.
Channel fader
This is the last control of the input section. Channel fader controls the overall level of the channel. The channel fader provides a small amount of gain (up to 12 db) and infinite attenuation (decrease). Fader control is specially created for the purpose of level control.
We have two types of Faders:
1. Rotary Faders For example – Equalization, Input gain control, etc.
2. Channel fader or straight Movable fader For example – stereo bus.
Pan control
Pan control on a Mixing console is used for placing a signal anywhere between left or right in the stereo field. Its mode of operation is by splitting a single signal from the input into two signals.These two outputs of the pan-pot, usually feeds the right and left channels of the stereo Mix bus. Also the signal can be placed in the middle or center which results in equal level in both L and R and hence no change in the perceived level.
Only 18 dB of level difference, is required between left and right channels to give the impression that a source is either fully right or fully left in a loud speaker stereo signal. But most pan-pots are designed to provide full attenuation of one channel when rotated fully towards the other, thereby changing the levels.
PFL/Pre Fader Listening
This section allows the signal to be monitored without routing it to the main outputs of the mixer. Fader listening also provides a means for listening to a signal in isolation in order to adjust its level or EQ. A PFL switch available on each channel, routes the signal before reaching the channel fader to the PFL bus. There is also a master PFL switch which changes the mixer’s monitor output to monitor the PFL bus.
Pan control
Pan control on a Mixing console is used for placing a signal anywhere between left or right in the stereo field. Its mode of operation is by splitting a single signal from the input into two signals.These two outputs of the pan-pot, usually feeds the right and left channels of the stereo Mix bus. Also the signal can be placed in the middle or center which results in equal level in both L and R and hence no change in the perceived level.
Only 18 dB of level difference, is required between left and right channels to give the impression that a source is either fully right or fully left in a loud speaker stereo signal. But most pan-pots are designed to provide full attenuation of one channel when rotated fully towards the other, thereby changing the levels.
This section allows the signal to be monitored without routing it to the main outputs of the mixer. Fader listening also provides a means for listening to a signal in isolation in order to adjust its level or EQ. A PFL switch available on each channel, routes the signal before reaching the channel fader to the PFL bus. There is also a master PFL switch which changes the mixer’s monitor output to monitor the PFL bus. Thanks for reading :)
image credit | teach me audio
PFL/Pre Fader Listening
REFERENCE