Transcript Audio Video Production Engineering

Metropolitan
Community
College
Audio Video Production
Engineering
Part 1 Audio
Sound and Hearing
The Human Ear
Outer Ear
Middle Ear
Inner Ear
Courtesy of Dr. John S. Oghalai
Used by permission
Courtesy of Dr. John S. Oghalai
Used by permission
Courtesy of Dr. John S. Oghalai
Used by permission
Noise Induced
Hearing Loss
Base level 85 dB for 8 hrs
Each 3 db increase 1/2 time
“A” weighting measurement
Most sensitive at 4 KHz
40 yrs @ 85dB = NIHL 8%
2
1
3
In phase
0
4
8
5
7
6
2
1
3
90 degrees out of phase
0
4
8
5
6
2
1
7
3
180 degrees out of phase
0
4
8
5
7
6
N
Magnetic
Field
S
0
-
Direction
of Travel
Magnetic
Field
+
.
0
-
+
Direction
of Travel
Direction
of Travel
0
Magnetic
Field
+
+
Magnetic field around wires
Polarity changes as current
direction changes
Review
Week 1
Output
Moving coil
attached to
Diaphragm
N
S
Dynamic
Microphone
Diaphragm
Diaphragm
(front plate)
Back plate
(fixed)
Output
Spacer
Capacitor
Microphone
How Speakers Work
http://electronics.howstuff
works.com/speaker5.htm
Block Diagrams
Used to make complex
circuits or systems easy
for the user to
comprehend and use
Block Diagrams
Most common symbol is a
square or rectangle
Triangles often used
Interconnected by lines
Block Diagrams
Direction of lines important
INPUTS – top and left
OUTPUTS - bottom and
right
Use arrows when not
standard
Tone
Li nk
Sat 2 M ont.
Sat 3 Si erra
TV Studi o A
Board Room
F.S. Li nk
STA 2A
STA 1A
STA -A
VP-2
VP-2
VP-2
VP-2
Gtw y out sel
D emod
PBS IR D
ESU-2 EC
ESU-2 AS
ESU-2 BN
ESU-2 BS
Quad Spli t
VCR 1
VCR 2
TCR M atri x 10
MC R Mi c
OCC
Bri dge 1
Bri dge 2
Bri dge 3
U NO 1
U NO 2
U NO 3
STA 2-7A
U NO 1
U NO 2
U NO 3
QS
STA 2-1A
STA 2-3A
STA 2-5A
none
ACR 2-8
ACR 2- 2
ACR 2- 4
ACR 2- 6
ACR 2- 9
OCC
Punch Bl ock
5-27
Mi c
R em in
5-28
R em 5-4
out
Spkr
5-3
Echo Can cel #2
DETAIL of ACR Connections
See
D etai l
Phone Bri dg e
75
AGC 3- 6
1-25
1-26
1-27
1-28
1-29
1-30
1-31
1-32
1-33
1-34
1-35
1-36
1-37
1-38
1-39
1-40
1-41
1-42
1-43
1-44
1-45
1-46
1-47
1-48
2-25
2-26
2-27
2-28
2-29
2-30
2-31
2-32
2-33
2-34
2-35
2-36
2-37
2-38
2-39
2-40
AGC 3- 5
74
76
AGC 3- 7
2-10
2-11
2-12
2-13
2-14
2-15
2-16
SRP 116
Gatew ay
N ET III
1-10
STA -A
1-11 STA 2-7A
1-12
1-13
1-14
1-15 STA 2-1A
1-16 STA 2-3A
1-17 STA 2-5A
1-18
1-19
1-20
1-21
1-22
1-23 STA 1-9A
1-24 STA 1-10A
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-8
FOC 16
FRC 108
SOC 516
EVC 103
EVC 106
FOC 206
STA 1-1A
STA 1-2A
STA 1-3A
STA 1-4A
STA 1-5A
VP-2
VBrick
VBrick
VP-2
VP-2
N ET II
STA 1B
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
EQ
A B
OCC
STA 3-4B
ACR 3- 3
ACR 3- 2
STA 3-9B
Bridge
Detail
VU Meter
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
ACR 3- 1
STA 3-9A
Eq uali zer
A
B
Test Mon
EVC 103
EVC 106
FOC 206
FOC 16
FRC 108
SOC 516
SRP 116
Gateway
N ET III
OCC
Bri dge 1
Bri dge 2
Bri dge 3
U NO 1
U NO 2
U NO 3
ESU-2 EC
Quad Spli t 1
Quad Spli t 2
Quad Spli t 3
Quad Spli t 4
VCR 1
VCR 2
Str eami ng
Gtwy in sel
Modul ator 1
Modul ator 2
D upe R ack
TV Studi o A
Board Room
F.S. Li nk
Li nk
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
3-11
3-12
3-13
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
3-35
3-36
3-37
4-25
4-26
4-27
4-28
4-29
4-30
4-31
4-32
4-33
4-34
4-35
4-36
4-37
4-38
4-39
4-40
STA 2-7B
STA 3-8A
STA 3-8B
Futur e
Mod ch Mod ch D upe R ack
Studi o A
Board Room
D V- 2
OCC
Bri dge 74
Bri dge 75
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
EXP 17
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
EXP 17
R S1 Test Mon
1
R S2 EVC 103
2
R S3 EVC 106
3
R S4 FOC 206
4
R S5 FOC 16
5
R S6 FRC 108
6
R S7 SOC 516
7
R S8 SRP 116
8
R S9 Gateway
9
EVC 103
10
EVC 106
11
FOC 206
12
FOC 16
FRC 108
SOC 516
SRP 116
AM 16/12 (#1) Audi o M atri x
Preset #1
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-25
3-26
3-27
3-28
3-29
3-30
3-31
3-32
3-33
3-19
3-20
3-21
3-22
4-42
3-43
3-44
3-45
3-46
3-10
3-14
3-15
3-16
3-17
3-18
3-23
3-24
5-1
3-34
3-38
3-39
3-40
3-41
3-42
3-47
3-48
5-25
Tone
Audio Moni tor
In #1 Spkr out
STA 1-1B
STA 2-7B
STA 2-3B
STA 1-4B
STA 1-5B
VP-2
VBrick
VBrick
VP-2
VP-2
Test Mon
EVC 103
EVC 106
FOC 206
FOC 16
FRC 108
SOC 516
SRP 116
Gateway
TCR Rooms
R S10 N ET III
1
R S14 Bri dge 3
2
R S15 U NO 1
3
R S16 U NO 2
4
R S17 U NO 3
5
R S18 ESU-2 AN
6
R S23 VCR 1
7
R S24 VCR 2
8
Gateway
9
N ET III
10
Bri dge 1
11
Bri dge 2
12
U NO 3
QS mi x
VCR 1
MC R mi c
AM 16/12 (#2) Audi o M atri x
Preset #1
Non-TCR Rooms
In #5
MX Out
Quad Spli t in 1
Quad Spli t in 2
Quad Spli t in 3
Quad Spli t in 4
STA 3B
STA 3-5A
STA 2-1B
STA 2-3B
STA 2-5B
VP-2
VP-2
VP-2
STA 1-9B
STA 1-10B
Mi c
Echo C XL
R em in
R em 5-2
out
Spkr
N ET III
Bri dge 3
U NO 1
U NO 2
U NO 3
ESU-2 AN
VCR 1
VCR 2
5-26
Metropolitan Community College
Master Control Audio Block
June 22, 2001 rev. 9/16/01
Craig C. Carlson, NCE
Functional Drawing of a typical VCR and TV
RF In
V
AV In
L R
Tuner
TV/Video or Input switc h
Play
VCR
VCR
TV
Record
VCR
TV
Mod
RF Out
RF In
V
TV/VCR s witch
(auto VCR when
play is selected)
L R
AV Out
V
AV In
L R
Tuner
TV
TV/Video or Input switc h
Picture
Sound
Amplifiers
Electronic devices used to
increase an electronic
signal level
Many types and kinds
Amplifier
Characteristics
Gain
Impedance input/output
Balanced input/output
Unbalanced input/output
Audio Amplifier Types
Pre amplifier
Buffer amplifier
Line amplifier/DA
Power amplifier
Pre Amplifier
Frequently used in low level
applications
Phonograph cartridge
Microphone
Intercom
Buffer
Often used to isolate one
circuit from another and
to match impedances
Line Amplifier/DA
Often used to increase
drive capability
Split signals to feed several
different pieces of equipt.
Usually no change in level
Power Amplifiers
Usually used to increase
current capability to drive
speakers and headphones
Decibel
Unit of measure Bel
Based on ratio
Used for both Acoustic and
electrical applications
dB formulas
Power
dB = 10 log (P1/P0)
Voltage and Acoustic
dB = 20 log (E1/E0)
dB as Unit of Measure
Requires a reference
3 and 10 rule (power)
6 and 20 rule
dB Standards
dB-SPL Acoustic sound
Pressure
Reference 0.0002 Dynes/sq
cm
dB Standards
0 dBm = 1mw>600 Ohm
load (.775 V)
0 dBu = .775 V
0 dBv = .775 V
0 dBV = 1 V
dB Standards
0 dBW = 1W
100W amplifier is 20dBW
1000W amplifier is 30dBW
SPL Meter
Microphone Amplifier Meter
A Weighting filter inverse of
equal loudness contours
B & C Weighting high end
of equal loudness contours
dB Meter
Specialized AC Meter with
scale calibrated in dB
VU Meter
Much the same as dB meter
Calibrated 0VU = _dB
Response peak to average
Analog, LED, Electronic
display
Review
Week 2
Wiring Characteristics
Impedance and Resistance
Impedance for AC circuits
Resistance for DC circuits
Both measured in Ohms
Balanced Wiring
Unbalanced Wiring
Input
+
Output
Audio Class of Service
Microphone level (-50 dB)
Line level (0 dB)
Speaker level
Video (1V Noisy)
RF (Saturates Amplifiers)
Data (HF Noisy)
Cable Characteristics
Conductor size (AWG)
Number of Conductors
Twist or no twist
Shielding
Insulation type
Review
Week 3
Equipment
Interconnect
Power Grounding
Earth/Chassis
Signal Grounding
Patch Panels
1
25
From Equipment (Outputs)
To Equipment (Inputs)
Normalling Jack Pair
24
48
The right way to do it.
Courtesy Rane Corporation (RaneNote 110)
Used by permission
Courtesy Rane Corporation (RaneNote 110)
Used by permission
Transformer Isolation
Courtesy Rane Corporation (RaneNote 110)
Used by permission
(A) Off the
Shelf cable
(B) 6dB sig.
loss
Courtesy Rane Corporation (RaneNote 110)
Used by permission
Courtesy Rane Corporation (RaneNote 110)
Used by permission
Courtesy Rane Corporation (RaneNote 110)
Used by permission
Review
Week 4
Mix Bus
Common point where
multiple signals are
combined
Summing point
Attenuators
Used to reduce signal level
Many types
Gain controls do not do the
same thing
Magnetic Tape
Back coat
Plastic base
Binder
Magnetic coating
Magnetic Tape
Several different coatings
Iron oxide
Chromium dioxide
Cobalt Doped
Metal
Magnetic Tape
Properties
Not covered in this class
Coercivity, Retentivity,
Sensitivity, Print through,
Dropout, and many more
Recording Process
Recording is non-linear at
audio frequencies
Bias current is needed to
make recording linear
Bias adjustment depends
on type of tape
Bias
Frequency Around 100 KHz
Applied to Erase Head
Modulated by Audio
Review
Week 5
Digital Audio
A to D Process
Storage
D to A Process
A to D Process
Sampling Rate
How many times per
second is the analog
signal looked at
CD is 44,100/Sec
32 KHz Broadcast
Sampling vs Frequency
Sampling rate needs to be
twice the frequency of the
highest audio frequency
needed
Analog Signal
Sample Points
Sample Rate
Anti-aliasing
A low pass filter us used to
limit high frequencies
prior to sampling
Quantization
The Value of each sample
Two 8 Bit words (16 bits)
yields 65,536 graduations
(used for each CD
channel)
Modulated
#132
1
Clock
2
4
8
16
32
64
128
The D to A Process
Demodulation
Error Correction
D to A Conversion
Sample and Hold
Low Pass Filter
Demodulation
Restores the recorded
signal to original ones and
zeros
Error Correction
Compensates for errors
introduced during the
recording process
D to A Conversion
Electronic process that
converts digital numbers
(samples) into analog
voltage (current)
Sample and Hold
Circuits that remove
“Switching Glitches” that
appear after D to A
processing
Low Pass Filtering
A circuit that does the final
smoothing of the analog
signal and removes any
high frequency noise
Wiring Considerations
Most digital connections use
standard XLR connectors
wired the same as
balanced audio
Do not bundle/run with
audio cabling
Wiring Considerations
Most MIDI hardware uses
DIN-5 pin connections
Pins 4 & 5 carry digital
signal Pin 2 is shield
50 ft maximum length