3 Band Graphic Equalizer

3Band Graphic Equalizer Circuit
Overview
The circuit illustrates the use of3frequencies to produce a graphic equalizer that will be used for acoustic signals.
Terminology
•Equalizer–a passive or an active electronic element or circuits(like tone control)used for the reason of altering or flattening the frequency response characteristics of a system
•TL072–a low noise JFET input operational amplifier with features such as common-mode input voltage range,high slew rate,operation without latch up,compensated internal frequency,high input impedance at the JFET input stage,low noise,low total harmonic distortion,protected from output short circuit,low input bias and offset currents,wide common-mode and differential voltage ranges,and low power consumption
•NE5532–an internally compensated low noise dual operational amplifier with features such as full power bandwidth up to140KHz,input noise voltage of8nV,common mode rejection ratio,9V/us slew rate,high DC voltage gain,32V peak to peak voltage swing,wide supply voltage range from3V to12V,unity gain bandwidth at10MHz,and internal frequency compensation
Circuit Explanation
One of the two kinds of equalizers is the graphic equalizer which originates its name from the rough graph of an audio’s altered frequency response which is formed by the glider settings on the front faceplate of an equalizer.The circuit pertains to a classic design by which it can regulate the tone of the acoustic signals into three different ways which includes the low,mid,and high frequencies.This is made possible by utilizing a tone control of the 3frequencies.A graphic equalizer typically consists of several audio filters or amplifiers with a specific audio range frequency.With the slope range of 18dB/oct,the amplification or boosting and attenuation or cutting of signals can be done.
The circuit is being supplied with 15V,but can also be supplied by a 9V up to 30V power source.The 0V should be connected to the pin 4of IC1,which will give half of the supply in the non inverting input of the IC1.Simultaneously,the pins 3and 5are similar which will not be connected to the ground.The tones of frequencies are being adjusted by the 100K Ohms linear potentiometer RV1for low frequencies,RV2for mid frequencies,and RV3for high frequencies.Part List
Application
Graphic equalizers are widely seen commonly in middle and high end stereo sound systems and other consumer products.They are used to correct the reduced level of high frequencies in early telephone systems as well as in modern digital telephone systems and in individual channels of a mixing board,where the sound waveform is being applied with equalization.They are available for use fine tuning of sound in personal computers.But most importantly,they are used as a standard practice in live sound reinforcement systems,professional recording studios,and some high fidelity systems where a spectrum analyzer is being used by a graphic equalizer to compensate for the room frequency response and room acoustics.Although graphic equalizers come in different designs,the all function by dividing the frequency response range into separate bands.R1-2=47Kohms
R3-4-5-12-13=
10Kohms
R6-7=3.3Kohms
R8-9=1.8Kohms
R10=270ohms
R11=22Kohms C1-11=10uF 25V C2=33pF ceramic C3=2.2uF 63V MKT C4=47nF 63V MKT C5-7=4.7nF 63V MKT C6=22nF 63V MKT C8=1.2nF 63V MKT C9-10=100nF 63V MKT C12=47uF 25V RV1-2=100Kohms Lin.RV3=470Kohms Lin.IC1=TL072,NE5532。