I want to connect phone output to a car radio. It has + and - inputs. When I connect left channel to the + input, there is good quality sound, but it's not as loud as CD player. If I invert right channel, then plug it in the - input, the sound should be 6 dB louder. I know that this can be done with an inverting amplifier, but is there a way to do this programmatically on android?
Btw is 1,5 degree phase change too much for bass? I simulated this circuit and these are the results. If I change R4 and R5 to 50 kΩ, phase and magnitude changes will decrease. On the other side, transient start up time and noise will increase, but besides that, will anything else be affected, like input bias current correction?
EDIT: This is Sound System manual(page 38).