physics 1251 the science and technology of musical sound unit 4 session 41 mwf midi

Physics 1251Physics 1251The Science and The Science and

Technology of Musical Technology of Musical SoundSound

Unit 4Unit 4

Session 41 MWFSession 41 MWF

MIDIMIDI

Physics 1251Physics 1251 Unit 4 Session 41Unit 4 Session 41 MIDIMIDI

What is the maximum frequency that What is the maximum frequency that can be represented by data that can be represented by data that was digitized at a sampling rate of was digitized at a sampling rate of 10 kHz?10 kHz?

By the Nyquist Criterion:By the Nyquist Criterion:

ffmaxmax = ½ R = ½ R

Or 5 kHz.Or 5 kHz.


11′ Lecture:′ Lecture:• MIDI is the acronym for “MIDI is the acronym for “MMusical usical

IInstrument nstrument DDigital igital IInterface.”nterface.”• MIDI is a control protocol that uses MIDI is a control protocol that uses

binary codes to remotely control binary codes to remotely control electronic musical instruments.electronic musical instruments.

• MIDI uses a current loop to MIDI uses a current loop to communicate in which current communicate in which current flowing means “0” and no current flowing means “0” and no current means “1.”means “1.”

• The Electronic wind instrument (EWI), The Electronic wind instrument (EWI), Electronic Valve Instrument (EVI) and Electronic Valve Instrument (EVI) and Electronic String Instrument (ESI) use Electronic String Instrument (ESI) use MIDI for control.MIDI for control.


80/2080/20Digitization is the process of Digitization is the process of converting a waveform into a series converting a waveform into a series of binary numbers that represent the of binary numbers that represent the amplitude of the signal at equal amplitude of the signal at equal intervals of time.intervals of time.

Pre

ssu

reP

ressu

re

[1000][1000]

22

[0100][0100]

22 [0010][0010]

22 [0001][0001]

22

Analog WaveformAnalog Waveform Digitized Digitized WaveformWaveform

Binary Coded Binary Coded DataData


80/2080/20MIDI (1982) sends, not a digitized MIDI (1982) sends, not a digitized wave form, but rather a binary coded wave form, but rather a binary coded performance message to control performance message to control electronic instruments electronic instruments (synthesizers).(synthesizers).

MasterMaster MIDI OutMIDI Out

SlaveSlave


MIDI—Physical: MIDI—Physical:

A five pin connector labeled “MIDI A five pin connector labeled “MIDI Out,” “MIDI In,” or “MIDI Thru.” Out,” “MIDI In,” or “MIDI Thru.” Communication is via current.Communication is via current.

MIDI OutMIDI Out

MIDI InMIDI In

Communication via Communication via current:current:

current = 0, no current = current = 0, no current = 11


MIDI—Physical: MIDI—Physical:

A five pin connector labeled “MIDI A five pin connector labeled “MIDI Out,” “MIDI In,” or “MIDI Thru.” Out,” “MIDI In,” or “MIDI Thru.” Communication is via current.Communication is via current.


MIDI Physical: MIDI Physical:

A MIDI chain can be assembled of up A MIDI chain can be assembled of up to 64 channels to 64 channels [0000][0000]22 to [1111] to [1111]22..

MIDI OutMIDI OutMIDI ThruMIDI Thru

Channel 00Channel 00 0101 02 02 03 03 04 04


MIDI Coding: MIDI Coding:

A MIDI command is a word of three A MIDI command is a word of three 8-bit bytes—status and 2 data bytes.8-bit bytes—status and 2 data bytes.

StatusStatus DataData[10010100][10010100][00111100][00111100][011111111]:[011111111]:

DataData

{09, 04}{09, 04}Note Note on,on,Channel 04Channel 04

100101 00100101 00001111 00001111 00 01111 111101111 1111

{060}{060} {255}{255}CC44

Speed 255,Speed 255,

((hardest)hardest)

ExampleExample::


80/2080/20A MIDI command is a binary code A MIDI command is a binary code that follows a prescribed syntax and that follows a prescribed syntax and grammar.grammar.

StatusStatus DataData[10000100][10000100][00111100][00111100][011111111]:[011111111]:

DataData

{08, 04}{08, 04}Note Note off,off,Channel 04Channel 04

100001 00100001 00001111 00001111 00 01111 111101111 1111

{060}{060} {xxx}{xxx}CC44

IrrelevantIrrelevant

ExampleExample::


MIDI Instruments:MIDI Instruments:

Electronic Wind Instrument (EWI)Electronic Wind Instrument (EWI)

MIDI signals:MIDI signals:

Note, pressure, Note, pressure, liplip



Electronic Valve Instrument (EVI)Electronic Valve Instrument (EVI)



Electronic String Instrument (ESI)Electronic String Instrument (ESI)

JanosJanos

Warren Bond—Warren Bond—Electric StradElectric Strad



Gesture Instruments (GI)hGesture Instruments (GI)h

““The The Glove”Glove”

Prof. Butch Prof. Butch RovanRovan


Summary:Summary:• MIDI is the acronym for “MIDI is the acronym for “MMusical usical

IInstrument nstrument DDigital igital IInterface.”nterface.”• MIDI is a control protocol that uses MIDI is a control protocol that uses

binary codes to remotely control binary codes to remotely control electronic musical instruments, electronic musical instruments, where a current loop is used to where a current loop is used to communicatecommunicate

• The Electronic wind instrument The Electronic wind instrument (EWI), Electronic Valve Instrument (EWI), Electronic Valve Instrument (EVI) and Electronic String (EVI) and Electronic String Instrument (ESI) use MIDI for control.Instrument (ESI) use MIDI for control.

physics 1251 the science and technology of musical sound unit 4 session 41 mwf midi

Documents

midi chain

electronic musical instruments

midimidi instruments

midi8020a midi command

midi outmidi incommunication

midi outmidi thruchannel

current loop

current means