How to test the audio input port
How do you tell if the Audio in port is functioning. I have tried everything and cannot get the computer to accept audio from the external mic. or guitar.
iMac (21.5-inch Mid 2011), OS X Mountain Lion (10.8.2)
The audio input port is line-level and will not pickup the week signal from an un-amplified mic or guitar pickup.
To test the audio input, try an iPod, stereo receiver or something that has a built in amplifier.
To use an un-amplfied mic or guitar, you will need something like a > MXL iBooster or a USB > Griffin iMic.