Combining multiple audio sources?

[ksafin]

Hi all,

I'm trying to work on a project in my car where I'm hoping to make use of the car's speakers for audible indication of certain things. Of course, at the same time, I'd like to retain the ability to play music.

I'm wondering if this can be as simple as using a summing amplifier from the various sources and having the single joined output.

For example, I'm adding two ultrasonic sensors to my rear bumper to tell me when cars are too close when merging. I'd like this to provide a slow or fast pinging on the car speakers when my blinkers are on.

So my current notion is to have the audio output of whatever is generating that signal (some DAC) and the audio output of my car go through a summing amplifier, and then into the car stereo amplifier to be amplified and played.

Will that work? Can I add any number of additional source nodes? Also, I imagine the output volume for each of the sources will be weighted proportionally. Is this correct?

Thanks!

 

[PaulStoffregen]

So my current notion is to have the audio output of whatever is generating that signal (some DAC) and the audio output of my car go through a summing amplifier, and then into the car stereo amplifier to be amplified and played.

Will that work?

It should work, if the signals have a common ground located close together.

Cars are notorious for audio ground loop noise. If the grounds are connected together close to each other, without significant current from all the other stuff in the car flowing through them, it will probably work.