How to listen to audio input to my MBP through audio in line?


macrumors 68000
Original poster
Oct 17, 2006
I have audio that is being sent to my MBP through an audio in line that I would like to monitor for audio quality. The only way I know how to listen in real time to the audio is by way of Audio Recorder, but it seems a little unnecessary to have a recording application open simply to listen to my media that is being sent in. Is there a feature already part of OS X that allows me to turn this on? I looked in system prefs, but couldn't find anything to enable this. I will resort to audio recorder if I have to, but would be very happy if this was already a feature.


macrumors 603
Oct 29, 2006
~119W 34N
Haven't seen that ability for a long time. (built-in)

I use "Line-In". It can route from any input to any output, with "Pass Thru" option. I use it sometimes to monitor Amateur Radio transceiver audio, either through another USB device (iMic) or the Mac's line-in.

It might be possible to set that up with Apple MIDI Setup, but it's a bit more cumbersome.

"Line-In" is very simple - you can hide it after launch, if it clutters your desktop too much.


macrumors regular
Sep 18, 2007
Upstate, NY

This thread saved me big time, by downloading the free LineIn program I am able to use an audio cable from my TV to my Macbook and listen via headphones to my tv without keeping my room mate awake. ( I know it would be much easier to just get a 3.5mm extension cable for my headphones but I'm in college, and I've gotta deal with what I've already got. THANKS AGAIN!