Reduce clicks when switching over cd4066
The problem is that when you switch on channels, you are sending DC current through the switch to your outputs. The bias voltage is not needed if you use a bipolar supply of +/- 7.5 volts (maximum). Then you can remove R1, R3, R5 and R7. The ground pin of the CD4066 (Vss) will now have -7 volt. R2, R4, R6, R8 become your ground reference for the signal.

The CD4066 will work with +/- 5 volts but the allowed signal intensity will be reduced.

Since it no longer has any DC voltage on the signal lines, there should be no clicking noise when changing inputs.

To get +/- 7.5 volts use LM7808(+8 volts) and LM7908(-8 volts) voltage regulators with a 1N4007 diode on the output to drop the voltage to a safe +/- 7.35 volts. Don't forget to add bypass capacitors on the Vcc and Vss pins to ground.