Akai MPCX User Manual page 217

LFO LFO is an acronym for low-frequency oscillator. The LFO generates a periodic oscillation at
a low frequency and features variable waveshapes. Similar to an envelope, an LFO can be
used to modulate a sound-shaping component.
MIDI MIDI stands for musical instrument digital interface. Developed in the early 1980s, MIDI
enables interaction between various types of electronic music instruments from different
manufacturers. At the time a communications standard for heterogeneous devices did not
exist, so MIDI was a significant advance. It made it possible to link various devices with one
another through simple, standardized connectors.
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 a MIDI synthesizer, the computer is the sender
and the synthesizer 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. To achieve this, a MIDI channel message is sent with each MIDI event.
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 1–16 are available for this purpose.
MIDI Clock The MIDI clock message transmits real-time tempo information to synchronize processes
among several connected devices (e.g., a sound generator's delay time to a MIDI sequencer).
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 a 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 a generated
note. A note-on message will start a note. Its pitch is derived from the note number, which
can range from 0 to 127. The velocity ranges from 1 to 127. A velocity value of 0 is equivalent
to a note-off message.
Normalize Normalization is a function to raise the level of a sample to its maximum (0 dB) without
causing distortion. This function automatically searches a sample for its maximum level and
consequently raises the entire sample's level until the previously determined maximum level
reaches 0 dB. In general this results in a higher overall volume of the sample.
Panning The process or the result of changing a signal's position within the stereo panorama.
Pitch-Bend Pitch-bend is a MIDI message. Although pitch-bend messages are similar in function to
control change messages, they are a distinct type of message. The resolution of a pitch-bend
message is substantially higher than that of a conventional controller message. The human
ear is exceptionally sensitive to deviations in pitch, so the higher resolution is used because it
relays pitch-bend information more accurately.
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