A sound card with a true (hardware) MIDI synthesizer built-in is highly recommended if you don't have an external MIDI module (expander). A software emulation using a soft synth application like Timidity or Fluidsynth in server mode will give acceptable response times for an interactive usage if your machine has a processor of 2 Ghz or more. On the other hand a simple FM synthesis card will give you a very low latency experience of karaKB, though the sound might not be so attractive at what is currently found on any wave sample device.

Though not strictly necessary, a MIDI keyboard with velocity and perhaps overall pressure sensing will considerably enhance your experience with karaKB. In such case you may need MPU401 MIDI interface, either independent or built-in in the sound card. Recent master keyboard just plug into the USB port of your computer. A stand alone MPU401 MIDI interface is enough if you have a sound module on your keyboard. And of course you'll need two MIDI (DIN) cables to connect your sound card or MPU401 interface to your external keyboard.

All software requirements are bundled with the karaKEY USB key.