This chapter, which is the first engineering/sequencing chapter in Part I, introduces you to digital audio and MIDI as well as the technologies used to manipulate them. Topics include digital audio, MIDI, decibel scales, clipping, and more. You will also continue to explore the piano roll editor within the digital audio workstation.
Figures
5.1 The perception of sound5.2 The perception of low frequencies5.3 The perception of high frequencies5.4 Relationship between frequency and pitch
5.5 Various representations of 440Hz5.6 Analogous properties of sound and music5.7 Visualization of the decibel scale in a virtual mixing board5.8 Analog to digital conversion with high sample rate
5.9 Analog to digital conversion with low sample rate5.10 Visualization of various bit depths5.11 Waveforms in the File Editor window of Logic Pro5.12 MIDI bi-directional communication
5.13 Graphic display of bi-directional communication between a synthesizer and a DAW5.14 A sample daisy chain setup
Flashcards
Click on the word to get the definition
frequency
the number of times per second that air molecules involved in a pressure wave vibrate back and forth in one complete cycle, which is in turn based on how quickly the source is vibrating. Frequency is perceived as a sound’s highness or lowness, similar to pitch in music.
Hertz (Hz)
a measure of frequency, with one Hz equaling one vibration per second.
amplitude
the intensity of energy in a given pressure wave, which is perceived by the human ear as loudness and expressed in dB or decibels (with 0dB representing the lower threshold for human hearing).
decibels (dB)
units of measure for amplitude.
clipping
digital overload distortion.
sample rate
the rate at which an analog-to-digital convertor takes samples or digital snapshots of an analog signal, measured in Hertz.
Nyquist theorem
a principle related to sampling stating that a sample rate should be set to at least two times the value of the highest frequency one wants to capture in order to create an accurate reproduction of an analog signal.
foldover
a type of aliasing or sonic distortion that is caused when a frequency is recorded that exists above one half of the sample rate.
aliasing
sonic distortion caused when a frequency is recorded that exists above one half of the sample rate.
bit depth
the number of bits used in each sample of an analog signal, corresponding to sample resolution.
DAW
an acronym for digital audio workstation, which is a piece of recording software designed to consolidate the workflows related to the many stages of production into a single location.
MIDI
an acronym for Musical Instrument Digital Interface, which is a protocol that allows two or more devices to connect and communicate with one another.
momentary configuration
a MIDI controller configuration that will send an on message when a certain apparatus is depressed and an off message when the apparatus is released.
toggle configuration
a MIDI controller configuration that will send an on message when a mechanism is depressed and remain in the on position until it is pressed down again.
CC messages
shorthand for continuous controller messages, which are the pieces of musical information that are sent via MIDI on a scale from 0 to 127.
