I have two audio systems, one in my living room and one in my office. My sound system in the living room is a Teufel Concept E450 Digital which sadly isn't compatible with receivers (since it's a complete system there's a filter so external sub-in simply doesn't work - I tried everything). I currently don't have the money to upgrade my stuff to an HDMI compatible solution so I wanted to go with a budget solution: I found this tutorial for a 5.1 switch box. As of now I actually just need the front and mid/sub channel as I don't use rear on either sound system.
The tutorial is great but there's a downside: I'm certain that when I switch the channels using this and forget that one of my systems volume is up, I probably die from popping sounds.
So I'd like to avoid this. I asked a friend of my parents' who told me that I basically only need a resistor and a capacitor which compensates the voltage changes when flipping the switch. It's been a long time since I worked with electronics and I'm not really sure where to start here. Can you give me some hints what I should focus on learning (besides the basics obviously)? I'm not sure what I have to take into consideration when it comes to analog audio signals, switching them and so on.
I do have a blueprint which I don't fully understand though. I guess this project shouldn't be too difficult, but I really need to freshen up my knowledge about electronics here. So any help and hint is appreciated.