Our research group is soon leaving to its annual strategy week and it was my task (again) to organize the Karaoke session. I would like to share my experiences with setting up a Mac as a Karaoke jukebox.
First, you need to have a good unidirectional microphone that only records the voice of the singer and not the sound from the speakers. This way, you prevent nasty feedback loops. The build-in microphone or headsets are unsuitable, since they record the sound from all directions, including from the speakers. I am using an AKG D60S, which is not sold anymore, but the D55S will do just fine. A good hand held microphone also gives the singer a more professional experience. They have something to hold onto and the microphone survives drops to the floor.
These semi-professional microphone use a different voltage and hence they do not work directly on your Mac. You cannot plug them into the line-in directly. The volume would be far too low. Instead, you need to have a sound interface that support different input levels. The cheapest one around is Griffin’s iMic. It works just fine for this purpose. Be careful that you buy a microphone (or adapter) that fits into the 3.5mm plug of the iMic.
Next, you need to be able to play your microphone through the speakers (playthru). Mac OS X does not support this directly. You can ether use free tools, such as LineIn or Playthrough FX, or you can use a shareware, such as Audiodia, that allows you to better control the audio levels. It even enables you to add effects. The echo function is particularly helpful for colleagues that are not the best singers.
You also need to have midi playback software that is optimized for Karaoke. You will need to have playlists to organize the wishes of the singers. The only reasonable cheap solution I could find is QMidi. It is a simple program that does the trick. Another alternative might be kJams. But of course you still need to have songs to sing. Look for .kar files on the internet. You may even find Karaoke collections. It is also good practice to print the list of songs, so that the singers can browse through them offline. For a group of 18 people you should have around 6 copies.
Last, you need to connect your Mac, ideally a notebook, to either a projector or a TV. It is a good idea to connect the audio-out of your computer to a real stereo, since the speakers of a TV are usually not powerful enough to be in balance with passionate singers.