Why doesn't my headset microphone work? I got a SteelSeries headset for Christmas and I plugged it into my MacBook Pro. The audio output works fine, but I am having issues with the audio input.

I saw this post which talked about some power issues to the microphone on the Mac Mini… I did not quite get what they were discussing, though.

I also found this link which says:


  Some microphones require power on the stereo mini jack and may not work on Mac systems. Try to check for Mac compatibility when buying USB microphone sets. Unamplified PC microphones often won't work.


The SteelSeries FAQ says I need a USB sound card to use the microphone with a Mac.

Does this mean I can't use my headset because it needs power from the computer? If yes, is there a workaround?

Does anyone know of any VERY cheap sound cards?

Why doesn't my microphone work?
On new Macbook Pros, there is no microphone input. What you have is a line-level input. Microphones that do not have integrated power and amplification (all cheap computer microphones/handsets) will not work when connected to the line-level input.

The connectors are exactly the same, but on the line input there is stereo input and ground, and on the microphone input there is mono input, voltage reference and ground. The input level is also different, with line level at around 1V and microphone level at 10-100mV.

To resolve the problem, you need to get one of the following:


a USB sound card which has a proper microphone input circuitry,
a powered, amplified microphone that can be used with line-level input, or 
a microphone preamplifier.


See also:


http://www.hobby-hour.com/electronics/computer_microphone.php
http://en.wikipedia.org/wiki/Line_level