Connect your microphone to the audio interface using an XLR cable and the "mic" port on the interface. Connect the interface to your computer using a FireWire cable.
Mount the microphone to a microphone stand using a clip or microphone holder. Retailers such as Musician's Friend, Guitar Center and Sam Ash stock a variety of these tools for varying sizes of microphones.
Place the microphone near the sounds of interest to be recorded. Move the keyboard to a position relatively distant from the microphone. Depending on the quality of your microphone, you may have to move the keyboard to a position near the main audio output source in order to capture its sound. If you would prefer to adjust the presence of the keyboard within a digital studio setting, follow the instructions in the following step.
Place the microphone in close proximity and record only the material from this instrument, ensuring that no other audio sources are present.
Record the remaining material you wish to use in the recording. Open your preferred digital audio workstation and import the two previously recorded tracks. Lower the volume of the keyboard track using the mixer utility. For added effect, adjust the stereo pan of the keyboard recording so that it plays solely out of the left or right speaker in order to create a dimensional, geographical effect.
Connect your keyboard directly to your computer using a USB cable if you are using a Musical Instrument Digital Information, or MIDI, enabled device. Select your keyboard as the designated MIDI input within the "MIDI I/O" or equivalently labeled settings menu of your audio workstation.
Press "record" to capture the MIDI data from your keyboard. You can now use the effects processors and recording techniques mentioned in the previous steps to create your desired aesthetic.