mix board 2 output in one input

Hello

I am a bit new to Arduino, and I wasn't sure for one of my project. I want to create a board that can combine two sound from two different sources and mix it together to create one sound. I also waned to create a volume controller for both of the sources. It would look like this :

music form iPhone-----------------

------------------> Earphones

Music from my computer----------

I already have the starter kit so the Arduino uno and different components. I read that I would need a shield to put on my own board for any types of audio.

So what should I use for my project ?

Thanks for reading

Of course mixing can be done digitally (mixing is done by summing) but most audio mixers are built around an [u]Analog Summing Amplifier[/u].

If you want to digitally control the volume, there are digitally controlled amplifiers (DCA) and you could stick a DCA at each summing-amplifier input and control it with the Arduino.

An op-amp normally needs bipolar power supplies, and in order to drive headphones you'd need to follow the summing amplifier by a headphone amplifier.

If you wanted to do it digitally, the Arduino analog-to-digital converter is only 10-bits and it's a bit slow so you can't get "CD quality" without an externa ADC. And since there's no built-in digital-to-analog converter, you'd need to add one. As with an analog design, you'd need a headphone amp on the output.