Graphic equalizers are used to tune a sound system to the room. Get an overview of the proper use of the graphic equalizer for a PA sound system in this free professional music video from an expert PA system designer.
Hi! My name is Kip Bradford and I am here on behalf of Expert Village. In this clip we are going to take a much closer look at the graphic equalizer and explain what that device is for. A 31 band equalizer is essential for a properly tuned sound system and what we use the graphic equalizer for is to tune our sound system to our room. The graphic equalizer 31 band will control frequency, band widths between 20 hertz and 20 kilohertz or 20,000 hertz which is the audible range. On a 31 band equalizer, it is called a 1/3 octave equalizer and that means that according to the ISO, the International Standards Organization, that the frequency is being controlled between these faders which is essentially volume control for the frequency band widths between 63 hertz and 80 hertz and so forth, that width is 1/3 octave. Most graphic equalizers will have a gain control with some metering to make sure that you don't overload the circuit. Often times we will find in our home graphic equalizer that people will do what we call the smiley face curve on the graphic equalizer. That is not what you should do on a sound reinforcement system. Again, this equalizer is to tune the system to the room. Tuning your system to your room means that you take the frequency response of your equipment and you will just read that in your specifications. Of course it won't do you any good to read it except to understand what frequency response really means. But you take the frequency response of your equipment and you take the frequency response of your environment because carpeting, chairs, people, architecture, paint all of those have absorption and reflection qualities of certain frequencies and so your room has a response as well. And you take two frequency response of your equipment, frequency response of your room and you combine them and you have an overall frequency response and then you use your graphic equalizer to control that, to basically neutralize the room, to give all of frequency responses in the audible range equal presence and you can't do that by ear. You have to use what is known as spectral analyzer.