Transcript Physics 1251 The Science and Technology of Musical Sound

Physics 1251
The Science and Technology
of Musical Sound
Unit 4
Session 41 MWF
MIDI
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.
Physics 1251
1′ Lecture:
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Unit 4 Session 41
MIDI
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.
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.
Digitized Waveform
Pressure
Analog Waveform
Binary Coded Data
[1000]2
[0100]2
[0010]2
[0001]2
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
Slave
MIDI Out
Physics 1251
Unit 4 Session 41
MIDI
MIDI—Physical:
A five pin connector labeled “MIDI Out,”
“MIDI In,” or “MIDI Thru.”
Communication is via current.
MIDI Out
MIDI In
Communication via current:
current = 0, no current = 1
Physics 1251
Unit 4 Session 41
MIDI
MIDI—Physical:
A five pin connector labeled “MIDI Out,”
“MIDI In,” or “MIDI Thru.”
Communication is via current.
Physics 1251
Unit 4 Session 41
MIDI
MIDI Physical:
A MIDI chain can be assembled of up to
64 channels [0000]2 to [1111]2.
MIDI Out MIDI Thru
Channel
00
01
02
03
04
Physics 1251
Unit 4 Session 41
MIDI
MIDI Coding:
A MIDI command is a word of three 8-bit
bytes—status and 2 data bytes.
Example:
Status
Data
Data
{09, 04}
Note on,
Channel 04
{060}
C4
{255}
[10010100] [00111100] [011111111]:
Speed 255,
(hardest)
100101 00001111 0001111 1111
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
{08, 04}
Note off,
Channel 04
{060}
C4
Data
[10000100] [00111100] [011111111]:
{xxx}
Irrelevant
100001 00001111 0001111 1111
Physics 1251
Unit 4 Session 41
MIDI
MIDI Instruments:
Electronic Wind Instrument (EWI)
MIDI signals:
Note, pressure, lip
Physics 1251
Unit 4 Session 41
MIDI
MIDI Instruments:
Electronic Valve Instrument (EVI)
Physics 1251
Unit 4 Session 41
MIDI
MIDI Instruments:
Electronic String Instrument (ESI)
Janos
Warren Bond—
Electric Strad
Physics 1251
Unit 4 Session 41
MIDI
MIDI Instruments:
Gesture Instruments (GI)h
“The Glove”
Prof. Butch
Rovan
Physics 1251
Unit 4 Session 41
MIDI
Summary:
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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.