mic needs a boost

[AudiGuy]

anyone know how to boost the volume of the line-in mic? i've raised the bar all the way up in system preferences and it still sounds low. my built-in mic works fine though..

 

[DigitalN.]

That is because it is a line in port, not a mic in, thus the microphone is getting no power. You need to go get an iMic, USB headset, or get an amp for the mic.