I have an embedded system powered by a 3.7V LiPo battery that will be connected to an iPod's headphone out cable. The embedded system will perform some DSP on the iPod's audio out signal and use OpAmps to mix it with a second signal.
Through some of my own measurement, I have discovered that the iPod's audio signal is about 2Vpk-pk and is centered around the ground wire provided in the headphones.
I know it is common practice to connect the grounds of the two systems together to make sure all voltages are at the same level between systems. Instead of connecting headphone ground to embedded system ground, could I connect it to the middle of a voltage divider in my system so that all the signals coming from the iPod are "centered" around (3.7V/2 = 1.85V)?