Connect the MIDI interface to your computer. Most will connect through a USB port. If yours does not, check the material provided with the interface for connection instructions.
Connect one of the five-pin plugs from your computer's MIDI interface, the connector designated for receiving data, to the MIDI Out terminal of your controller. The MIDI controller is usually an electronic piano keyboard, and the MIDI terminals are usually on the rear panel. The five-pin MIDI plug is at the end of a cable attached to the interface and may be imprinted with something like "To MIDI Out".
Connect the other plug from your computer's MIDI interface, the one designated for receiving data from the computer, to the MIDI In terminal of a MIDI sound module. The plug may be imprinted with something like "To MIDI In". Note that if you are using a keyboard controller with its own sound module or synthesizer built in, both MIDI plugs are connected to the keyboard.
Install a MIDI software sequencer on your computer, if you don't already have one, and configure the sequencer to use the appropriate MIDI In and MIDI Out ports for sending and receiving MIDI data to and from your sound module and controller. This is usually done from the Options or Preferences menu, and is often referred to as "MIDI Setup". Your sequencer should display which MIDI ports are installed and available, making it easy to select the appropriate ones.
Click on the "Record" button of your sequencer. As you play music on your keyboard controller, the music is digitized and sent to your computer, where the sequencer allows you to arrange the music data into tracks. You are able to record music on 16 separate tracks.
Assign a MIDI instrument for each music track displayed in your sequencer. Follow directions in the user's guide for your particular sequencer. Most standard MIDI sound modules offer a choice of 128 musical instruments. For example, you might have a piano track plus up to 15 additional tracks with instruments such as guitar, bass, strings, trumpet and percussion.
Set MIDI controllers (not the same as a MIDI keyboard controller), such as note volume, pan, pitch bend, and pedal sustain and release. You may set these parameters for each track of music shown in your sequencer, allowing you as the arranger to optimize each instrument as well as balance the overall output.
Click on the sequencer's "Play" button to play back the sequenced, or arranged music. Your sequencer will instruct the computer to send the music data through the computer's MIDI Out port into your module's MIDI In terminal. To preview or monitor your work, you must connect the sound module to an audio system, such as an amplifier with speakers or headphones.
Save your music into a file once you are satisfied or finished working with your arrangement. The software sequencer saves MIDI data to a Standard MIDI File, with the file extension .MID or .SMF. Later, you can reload these files and play back your music, or you can continue editing and refining your work.
Connect a standard MIDI cable from the MIDI Thru terminal of a MIDI sound module to the MIDI In of an additional module. MIDI data will be sent to Module 1, then passed on to Module 2 through the first module's MIDI Thru terminal. In this manner, you can couple together multiple sound modules and take advantage of the varying instrumental sound qualities of each.
Disable MIDI channels that you do not wish to use. Sixteen channels of music data flow from one module to the other via the MIDI Thru ports. So, if you want only tracks 1 to 4 to sound on Module 1, let's say because the guitar and percussion sounds are superior, but want tracks 5 to 16 to sound on Module 2, because the strings and brass are better, you must silence tracks 5 to 16 on Module 1 and tracks 1 to 4 on Module 2. Otherwise the sounds from one module conflict with the sounds coming from another. In some units this is controlled from the module's front panel; some sequencers allow this to be set with the software.
Connect the Audio Out jacks of each sound module to a mixer with amplifier, and listen to your music through monitors such as speakers or headphones. Now you can make the final touches in balancing the output from all MIDI sound sources.