To deepak:
the project require a preamp stage that amplified the signal and then it will switch by using a transistor(which i am not sure how it is done), the switching will switch to either a normal music bandwidth stage name as music or it can be switch to a bandpass filter which has a freq of 300-3300 Hz name as voice... and then after this it will then be amplified using TDA7052A with volume and mute control.. when music stage is turn on LED red will light up, when voice stage is turn on LED yellow will light up and when mute is on LED green will light up.
i am not sure on which preamp i need to use and how to use a transistor as a switch, components such as uA741, 2N2222, toggle switch.. etc are given.