Manual

205
Glossary
A lot of the terms in this manual are based on the MPC parameter names. This glossary briefly explains many of the
technical terms used throughout.
A
ftertouch
The majority of contemporary keyboards are capable of generating aftertouch messages. On this
type of keyboard, when you press harder on a key you are already holding down, a MIDI aftertouch
message is generated. This feature makes sounds even more expressive (e.g., through vibrato).
A
liasing
A
liasing is an audible side effect arising in digital systems as soon as a signal contains harmonics
higher than half the sampling frequency.
A
mount
Describes to which extent a modulation source influences a given parameter.
A
mplifier
A
n amplifier is a component that influences the volume level of a sound via a control signal. It
can be modulated by a control signal (e.g., generated by an envelope or an LFO).
A
ttac
k
A
n envelope parameter. This term describes the ascent rate of a time-relevant process (e.g., an
envelope from its starting point to the point where it reaches its highest value). The attack phase
is initiated immediately after a trigger signal is received (e.g., after you play a note on a trigger
pad or a keyboard).
Bit Rate
Bit rate (also known as word length), is the number of bits used to store the level information of
each single sample slice within a whole sample. The higher the bit rate, the more precise the
information about a sample (i.e., its dynamics’ resolution). Normal audio CDs are 16-bit. MPC
supports full 24-bit resolution.
Clipping
Clipping is a sort of distortion that occurs when a signal exceeds the maximum value that can be
handled by a signal processing system it is fed into. The curve of a clipped signal is dependent
on the system where the clipping occurs. In the analog domain, clipping effectively limits the
signal to a given maximum level. In the digital domain, clipping is similar to a numerical overflow,
resulting in negative polarity of the signal’s portions exceeding the maximum level.
Control Change
(Controllers)
MIDI messages enable you to manipulate the behavior of a sound generator to a significant
degree. This message essentially consists of two components:
• The controller number, which defines the parameter to be influenced. It can range from 0
to 127.
• The controller value, which determines the extent of the modification.
Controllers can be used for effects such as slowly swelling vibrato, changing the stereo panning
position and influencing filter frequency.
Cutoff
The cutoff frequency is a significant factor for filters. A low-pass filter for example dampens the
portion of the signal that lies above this frequency. Frequencies below this value are allowed to
pass through without being processed.
Decay
Decay describes the descent rate of an envelope once the attack phase has reached its
maximum and the envelope drops to the level defined by the sustain value.
Envelope
A
n envelope is used to modulate a sound-shaping component within a given time. For instance,
an envelope that modulates the cutoff frequency of a filter opens and closes this filter over a
period of time. An envelope is started via a trigger, usually a MIDI note. The classic ADSR
envelope consists of four individually variable phases: attack, decay, sustain, and release.
A
ttack, decay and release are time or slope values, while sustain is an adjustable level. Once an
incoming trigger is received, the envelope runs through the attack and decay phases until it
reaches the programmed sustain level. This level remains constant until the trigger is terminated.
The envelope then initiates the release phase until it reaches the minimum value.