Waldorf AFB 16 User Manual - page 36
Appendix
AFB16 User´s Manual
68
MIDI
The acronym MIDI stands for "musical instrument digital
interface." It was developed in the early '80s so that
diverse types of electronic musical instruments by
different manufacturers could interact. At the time a
communications standard for heterogeneous devices did
not exist, so MIDI was a significant advance. It made it
possible to link all devices with one another through
simple, uniform connections.
Essentially, this is how MIDI works: One sender is
connected to one or several receivers. For instance, if you
want to use a computer to play the Pulse, then the
computer is the sender and the Pulse acts as the receiver.
With a few exceptions, the majority of MIDI devices are
equipped with two or three ports for this purpose: MIDI
In, MIDI Out and in some cases MIDI Thru. The sender
transfers data to the receiver via the MIDI Out jack. Data
are sent via a cable to the receiver's MIDI In jack.
MIDI Thru has a special function. It allows the sender to
transmit to several receivers. It routes the incoming signal
to the next device without modifying it. Another device is
simply connected to this jack, thus creating a chain
through which the sender can address a number of
receivers. Of course it is desirable for the sender to be
able to address each device individually. Consequently,
there is a rule which is applied to ensure each device
responds accordingly.
MIDI Channel
This is a very important element of most messages. A
receiver can only respond to incoming messages if its
receive channel is set to the same channel as the one the
sender is using to transmit data. Subsequently, the sender
can address specific receivers individually. MIDI
Channels 1 through 16 are available for this purpose.
MIDI Clock
The MIDI Clock message determines the tempo of a piece
of music. It serves to synchronize processes based on
time.
Modulation
A modulation influences or changes a sound-shaping
component via a modulation source. Modulation sources
include envelopes, LFOs or MIDI messages. The
modulation destination is sound-shaping component such
as a filter or a VCA.
Note on / Note off
This is the most important MIDI message. It determines
the pitch and velocity of every generated note. The time
of arrival is simultaneously the start time of the note. Its
pitch is derived from the note number, which lies
between 0 and 127. The velocity lies between 1 and 127.
A value of 0 for velocity is similar to "Note Off".