[zebelkhan]

I have a question that I hope someone will be able to give me an easy answer to. Sorry for the long post but I have no choice but to explain from beginning.

I have my carputer audio output connected to the auxiliary input of my PAC audio. The problem I have is that I can only choose to listen to audio coming from the PC (mainly GPS), or from the car's OEM CD/radio but not both at the same time. So when I have the radio on, there is no GPS sound, and when I listen to GPS, I can't have any music! :3:

To fix this, I have purchased a KH style relay (a regular mechanical relay which has multiple contacts) that can switch between two “4 wire” sources. I am thinking to connect the audio output of the carputer to the input terminals of relay and have one set of the outputs connected to the PAC audio and the other set to a small auxiliary speaker. The negative 12 volt line from PAC audio will activate the relay and route the audio from the carputer to the regular speaker if I am listening to radio/CD, and switch it back to Bose (via PAC audio) when I press the SAT button. This way I can listen to radio/CD and have GPS sound through the extra speaker at the same time. and switch back when I need to. Later on when I have all my audio loaded into the carputer I will probably have less use for the cars' CD player and I can take the relay out but for now I need it.

My question is: How will the audio quality going to suffer when sounds from carputer pass through the relay? For now is just GPS but eventually I will have MP3 music playing through it too. Will I have interference, noise or cross talk because of that? Is there a way to keep the audio quality from degrading? How? Any insight would be greatly appreciated.

 

[10413]

I'm sure one of the electronics whiz-types we have lurking around here will have a better answer for you, but here's my thought... since I'm not familiar with relays I won't try to venture any theories there. My suggestion is -- why not use a small mixer to mix the audio channels together?

 

[zebelkhan]

Good idea but I am not sure if that can be done here. The audio source from the computer goes to PAC audio auxiliary input and enters the head unit through the satellite connection. The radio and CD players are connected to the head unit internally so ther isn't any place that I could use a mixer in.

 

[GripperDon]

zebelkhan I'm not ignoreing the question, There are so many variable impedance, loading, etc. I just don't know. You may have to try it to find out. Maybe mock it up with out the relay to hear it in temp form.

 

[jaak]

I agree, it depends how you put it together, that determines what problems, if any, will occur. If you do it right, you should be fine.

If you can post a wiring diagram of what you want to do, we can look at that and ask questions or make suggestions.