Physics 1251 The Science and Technology of Musical Sound

1
Physics 1251The Science and Technology of
Musical Sound

• Unit 4
• Session 41 MWF
• MIDI

2
Physics 1251 Unit 4 Session 41 MIDI

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

By the Nyquist Criterion fmax ½ R Or 5 kHz.
3
Physics 1251 Unit 4 Session 41 MIDI

• 1' Lecture
• MIDI is the acronym for Musical Instrument
  Digital Interface.
• MIDI is a control protocol that uses binary codes
  to remotely control electronic musical
  instruments.
• MIDI uses a current loop to communicate in which
  current flowing means 0 and no current means
  1.
• The Electronic wind instrument (EWI), Electronic
  Valve Instrument (EVI) and Electronic String
  Instrument (ESI) use MIDI for control.

4
Physics 1251 Unit 4 Session 41 MIDI

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

Analog Waveform
Digitized Waveform
Pressure
1000201002 00102 00012
Binary Coded Data
5
Physics 1251 Unit 4 Session 41 MIDI

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

Master
MIDI Out
Slave
6
Physics 1251 Unit 4 Session 41 MIDI

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

MIDI Out
MIDI In
Communication via currentcurrent 0, no
current 1
7
Physics 1251 Unit 4 Session 41 MIDI

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

8
Physics 1251 Unit 4 Session 41 MIDI

• MIDI Physical
• A MIDI chain can be assembled of up to 64
  channels 00002 to 11112.

MIDI Out
MIDI Thru
Channel 00 01 02 03 04
9
Physics 1251 Unit 4 Session 41 MIDI

• MIDI Coding
• A MIDI command is a word of three 8-bit
  bytesstatus and 2 data bytes.

Example
Status
Data
Data
10010100
00111100
011111111
09, 04
060
255
Note on,
C4
Speed 255,(hardest)
Channel 04
100101 00
001111 00
01111 1111
10
Physics 1251 Unit 4 Session 41 MIDI

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

Example
Status
Data
Data
10000100
00111100
011111111
08, 04
060
xxx
Note off,
C4
Irrelevant
Channel 04
100001 00
001111 00
01111 1111
11
Physics 1251 Unit 4 Session 41 MIDI

• MIDI Instruments
• Electronic Wind Instrument (EWI)

MIDI signals Note, pressure, lip
12
Physics 1251 Unit 4 Session 41 MIDI

• MIDI Instruments
• Electronic Valve Instrument (EVI)

13
Physics 1251 Unit 4 Session 41 MIDI

• MIDI Instruments
• Electronic String Instrument (ESI)

Janos
Warren BondElectric Strad
14
Physics 1251 Unit 4 Session 41 MIDI

• MIDI Instruments
• Gesture Instruments (GI)h

The Glove
Prof. Butch Rovan
15
Physics 1251 Unit 4 Session 41 MIDI

• Summary
• MIDI is the acronym for Musical Instrument
  Digital Interface.
• MIDI is a control protocol that uses binary codes
  to remotely control electronic musical
  instruments, where a current loop is used to
  communicate
• The Electronic wind instrument (EWI), Electronic
  Valve Instrument (EVI) and Electronic String
  Instrument (ESI) use MIDI for control.