This is a full size 40 Watt megaphone with a built in voice changer taken from a children’s voice changing megaphone.
I used the voice changer circuit from the megaphone pictured to the left.
The circuit has been modified to include a pitch adjustment and a balance control.
I mounted the controls for the voice changer in the megaphone mouth piece. On the left is the balance, right is pitch and the slider switch in the middle is the mode setting.
Here’s the wiring diagram for modifying the voice changer circuit. The way I wired it in this project differs from the schematic below in that I wired the speaker out from the voice changer circuit into the mic in of the larger megaphone.