Now that you have voted this instructable let's get started and make a whole speaker set wih mic that operates on 9 to 12v battery.
The amplifier that you see in the photo is made by me but I have enclosed it in an empty box of an old amplifier wich was fried years ago but you can make your own box of wood.
Step 1: Amplifier
Ceramic capacitor 0.01 uf (number 103)
Ceramic capacitor 0.47 uf (number 473)
10 ohm 1/4 watt resistor
5 k ohms potentiometer (for gain control)
100 ohms potentiometer (for volume control)
100 uf electrolyte capacitor
220 uf electrolyte capacitor (for bass)
The 3.5mm pin has three pins in it the longest one is the negative for both left and right speaker and one of the small pins is positive for left speaker and the other is the positive for the right speaker. It is very loud if powered by 12v dc. The circuit is given in this step and a photo of the amplifier made is also given in this step