Equalization - Posted on 2015-03-15 by Alexander Schug

The idea of Equalization started back in the 1860's because of the need to manipulate electrical signals through submarine telegraph cables. These signals had to be sent extremely slow in morse code in order for the people recieving the message to understand it. William Thompson who was an engineer and physicist questioned the reasoning to the speed that these signals had to be sent and knew that the problem was in the design of the cable.  He ended redesigning the cable allowing it to have greater capacitance. Thompson also invented a device that enable some more control of the single by reducing the dispersion. Another man named Oliver Heaviside came up with the idea of inductors which resist changes in the electric current as the signal passes through it at consistant intervals through out the cable to diminish dispersion and attenuation. In the 1930's people started to hear how terrible audio playback systems were reproducing sound. A man named John Volkman had perfected the idea of a fixed equalizer as in an outter peice that can actually make reproduced sound more clear than it was to start off with. A little later on a man named George Massenburg pushed the idea of EQ forward came up with the idea of parametric EQ. There are three signficant parts of an EQ which are Inductors, Resistors, and Capacitors. A Capacitors works by storing electrical energy until the limit is reached and then discharges it. The amount of energy a Capacitor holds is measured in Farads. An inductor is a coil of wire that surrounds a conductor. An inductor diminishes changes in voltage to allow more even flow of energy. A Resistor resist the flow of energy. With an EQ you can add or subtract frequencies from a signal. In order to do so there needs to be parameters to manipulate. The Center Frequency allows you to choose where on the EQ you want to distort. Bandwith determines how wide the range of the frequency will me used. Boost and cut allows increase or decrease in amplitude of that frequency range. You use different kinds of filters to do this. High pass filters work by allowing frequencies above the assigned cuttoff to pass through and the Lowpass filter of course does the exact opposite. Peaking filters are used in the middle of the frequency spectrum and its shaped like a bell. There are also Low shelf and High shelf filters which are at each end of the frequency spectrum. Notch filters are used to manipulate frequency percisley between the High and Low shelf filters on the EQ. Now there are different kinds of EQ's called Graphic, Program, and Parametric. With a Graphic EQ the only parameters you can be set are boost and cut with verticals sliders of the ranges presented on the EQ. A program EQ allows you to boost, cut, and sweep frequencies but also may have predetermined ranges. A parametric EQ pretty much allows you to effect all the parameters enabling specific frequency modulation. Now you can just have a plethora of EQ plug ins in your DAW which can be Parametric and not even have to use an outter peice.