Understanding MIDI - MIDI Ports, Channels, and the General MIDI Standard

In a previous article I wrote the basic definition aboutinstrument's MIDI IN port. This is useful to chain several
MIDI (Musical Instrument Digital Interface) and howMIDI instruments receiving data from a single MIDI OUT
modern musicians can use it in their independentport from the computer (for example, to play multiple
productions. This time I will write about the technicalstring parts using different string sounds on different
side of MIDI, including MIDI ports that are available, MIDIkeyboards).
channels and how to use them, and the General MIDIIn more recent technology, keyboards can be
Standard that allows a MIDI file to be read consistentlyconnected to computers via straight USB connection
over a variety of MIDI-capable instruments (hardwarewithout needing a USB to MIDI converter. The
and software).downside is that it limits your ability to chain multiple
MIDI PortsMIDI instruments together.
As in every other audio or music related technology,MIDI Channels
MIDI has an IN and OUT port. To explain the use ofThere are 16 MIDI Channels for every 1 MIDI Port. That
these two ports, lets use the example of a MIDImeans any one MIDI Port can send and receive 16
keyboard and a computer (in this case a MIDI to USBchannels of MIDI data. Each MIDI channel contains all
converter is necessary for the computer). The MIDIthe MIDI information regarding a particular track. For
OUT port on the keyboard is connected to the MIDI INexample, if Track 1 is Acoustic Piano, then MIDI
port on the computer. This means that the keyboardChannel 1 will contain the note pitch, note length, sustain,
sends MIDI data to be played back or recorded insideand other performance data to be played back by a
the computer. Vice versa, the MIDI IN port on thesound source. The sounds played back are
keyboard can be connected to the MIDI OUT port ofdetermined by the Bank and Patch number inside the
the computer allowing the recorded MIDI data insideMIDI Channel. For example, using the General MIDI
the computer to be sent back to the keyboard inStandard, Acoustic Piano is always Patch #1 and
order for the keyboard to play back the MIDI data (thisAcoustic Guitar (Nylon) is always #25. There are 128
means you can record yourself playing, edit the MIDIPatches overall.
data in a music software, and then play it back on theHaving 16 MIDI channels per port allows you to
keyboard and record the audio coming out thecompose a song using 16 different parts. For example
keyboard for a better edited performance).you can use Channel 1 for the melody Part using a
Besides MIDI IN and OUT, there is a MIDI THRU portsaxophone sound (Patch #65 Soprano Sax), create
that is sometimes available on a MIDI instrument. MIDIthe comp part using a piano (Patch #5 Electric Piano 1),
THRU functions to pass on the MIDI data received atand compose the rhythm part using bass (Patch #34
the MIDI IN port to another MIDI instrument or device.Electric Bass finger) and drums (using MIDI Channel 10,
Take for example the keyboard receives MIDI dataa channel that is reserved especially to play percussion
from the computer in it's MIDI IN port. If the keyboardsounds regardless of the patch number you program
has a MIDI THRU port, it can continue the data itin). If you need more channels, then you need more
receives from the computer to another MIDIMIDI ports!