The circuit, (based on the well-known and versatile NE555) is a timer with a delayed start.
When the circuit is empowered, the integrated circuit delays the activation of the relay connected to its pin 3. The delay time can be adjusted with the P1 potentiometer. We can increase the delay even more if we increase the value of C1.
The positive output of the amplifiers loudspeakers is connected to the relay’s entrance and its output is connected to baffle.The power of this circuit is 12 volts.
The wiring diagram.
The circuit board.
The scheme and the circuit board should be in the same folder and they should have the same name, you should only change the extension to .sch for the scheme and to .brd for the circuit board, this way both of them will be recognized and associated by Eagle.
The file is compressed, to extract it, you should enter a password: www.kemisa.es
If you don´t know how to make a printed circuit boards click here.