10
MIDI Tutorial
About MIDI - MIDI messages used by the K-Station
It is recommended that this chapter is read carefully if you are unfamil-
iar with how MIDI works. Experienced users can skip this chapter and
move on to the next chapter Main Features and Operation on page
13.
MIDI is an acronym for Musical Instrument Digital Interface. The MIDI
standard was devised in the early 80’s as a means for allowing musical
instruments to communicate with each other as well as with other
devices such as sequencers and computers. Before the advent of
MIDI, it was very difficult (if not impossible) for instruments to effective-
ly communicate with each other, especially if they had been made by
different manufacturers. Nowadays, most types of electronic musical
equipment are equipped with a MIDI interface fitted as standard,
including synthesizers, drum machines, samplers, sequencers, com-
puters and even some effects units.
The MIDI standard allows many different instruments to be controlled
at once (say from a sequencer) using the same network of MIDI
cables. Each instrument in the MIDI chain is usually assigned its own
unique MIDI channel and will only respond to information that it may
receive on that particular channel. The MIDI standard allows for sixteen
different channels to be assigned to the various instruments in a MIDI
network, which of course means that it is possible to have up to sixteen
instruments playing simultaneously within a MIDI system.
It might be felt that being restricted to just sixteen MIDI channels would
be a little limiting, especially for very complex pieces of music.
However, some sequencers and MIDI ports for computers offer a neat
way around this problem. They can offer several different MIDI outputs,
each of which is treated as a separate MIDI system in its own right with
its own set of sixteen MIDI channels.
The K-Station has three MIDI sockets fitted at the rear, labeled ‘In’,
‘Out’ and ‘Thru’. Each one of these sockets has a specific purpose :
The MIDI In socket is used to receive MIDI information to the K-
Station, such as telling it which notes to play from a sequencer for
example.
The MIDI Out socket transmits any MIDI information which might be
generated by the K-Station. For example, if a note was played on the
K-Station’s keyboard or one of the knobs were moved on the front
panel.
The MIDI Thru socket simply re-transmits any MIDI information that
has been received at the MIDI In socket. This socket is useful for con-
necting other instruments into the same MIDI network. By connecting a
cable from the K-Station’s MIDI Thru to another instrument’s MIDI In
socket, both the K-station and the second instrument could be con-
trolled simultaneously from a sequencer.
As seen above, if desired, the process can be repeated; a third instru-
ment could be added to the same MIDI network, simply by connecting
a cable from the second instrument’s MIDI Thru to the third instru-
ment’s MIDI In, and so on.
Some instruments may not have a MIDI Thru socket fitted. In these
cases, the instrument should be placed at the end of the MIDI chain or
a Thru box should be incorporated into the MIDI system.
A Thru Box simply provides a number of identical MIDI Thru sockets
from a single MIDI In.
It is important to realise that MIDI information flows in one direction
only along the cable. It is not possible to have a MIDI In socket con-
nected to another MIDI In socket for example. If this were done, the
MIDI network would simply not work! In fact, the only routings allowed
are MIDI Out to MIDI In or MIDI Thru to MIDI In.
Some devices known as controllers are equipped with only a single
MIDI Out socket and are used exclusively to generate MIDI data for
controlling other instruments. Examples of common MIDI controllers
are controller keyboards (these are simply keyboards with no synthe-
sizer attached), drum percussion pads or footswitch controllers.
The K-Station is capable of transmitting and responding to various
types of MIDI events. These are as follows :
NOTE MESSAGES
A note message is transmitted every time a key on the K-Station’s key-
board is pressed down or released. When a keyboard note is pressed
down, the MIDI message also includes velocity information. The veloci-
ty value in the MIDI message represents how hard the key was
pressed down. This velocity value can be used to add dynamics to the
sound, depending on how hard the note was played.
CONTROL CHANGE MESSAGES
These messages are transmitted whenever one of the K-Station’s
knobs or sliders are moved on the front panel. Most settings within a
menu will also transmit MIDI control change messages when the set-
ting is altered with the DATA knob. The MIDI specification allows for
128 different types of controller message. These are often referred to
as Continuous Controllers (CC0 to CC127).
Some controllers are rigidly defined by the MIDI standard for specific
functions. For example, CC1 is always used for the modulation wheel.
Therefore, whenever you move the K-Station’s modulation wheel, it will
transmit MIDI control change information using CC1. All other makes of
synthesizers will also use CC1 for modulation wheel data. However,
certain other control change numbers have no set purpose within the
MIDI specification. For example, whenever the K-Station’s Filter FRE-
QUENCY knob is moved, it will transmit using CC105. There is no
guarantee however that other makes of synthesizer will use this control
change number for the same purpose.
The K-Station actually has many more than 128 different control set-
tings that can be transmitted by MIDI, but because the number of dif-
ferent types of control change message is limited to just 128, the K-
Station sometimes has to use a more complicated arrangement for
transmitting certain settings. This method uses what is known as
NRPNs.
Out
Out
In
In
In
In
In
Thru
In
InThru
Thru
Thru
Thru
Sequencer
Sequencer
Synth [1]
Synth [1]
Synth [2]
Synth [3]
Synth [2]
Synth [3]
‘Chain’ method of connecting three MIDI
devices to a sequencer
‘Star’ method of connecting three MIDI
devices to a sequencer
MIDI Thru Box
About MIDI
MIDI messages used by the K-Station
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