- MacBook Pro 2011 running OS X 10.8 (Mountain Lion)
- Linein (http://www.rogueamoeba.com/freebies/)
- Spotify with tunewiki (https://www.spotify.com/us/)
- Logitech X-140 2.0 Speakers (http://www.amazon.com/)
- Audio-Technica ATR2100-USB Cardioid Dynamic USB/XLR Microphone (http://www.amazon.com/)
For the hardware setup simply plug the speakers into the headphone line out and plug the microphone into a USB port. One mistake that I initially made was that I bought a standard mic with 3.5mm jack and just plugged it into the mic input on the mac. It turns out that the input voltage on that setup is way too low and I could barely hear the microphone. One solution would have been to buy a little preamp and plug the mic into that and then plug the preamp into the computer but I found the mic listed above on amazon for less than the preamp. One other mic note is that you need to make sure to buy a directional microphone otherwise you'll pickup the speakers and get nasty feedback. My final hardware comment is that if you plan to copy my setup exactly I'm happy with the speakers given my usage, however, they are the weak link in the setup. The mic sounds great and the speakers are not bad but not great.
Now for the software.
The one trick in the process is getting the mic to output to the speakers. This is done by launching linein and selecting the USB microphone as the input and the built in output headphones as the output. Then just click pass though and you should here the mic over the speakers.
Once you have spotify installed just go to the app finder and add tunewiki. Tunewiki has the lyrics to tons of songs and if you highlight it while playing a song on spotify it will display the lyrics in time with the song.
Finally I used the built in OS X utility Audio Midi Setup to control the mic volume. Simply highlight the USB mic and you can control the output volume of the mic. For the song volume use the spotify volume control and the master volume can be controlled by the usual mac interface.
Now all you need are a couple of sake bombs and you should be good to go....