Exam Revision Flashcards
(155 cards)
1
Q
Which instrument would produce the longest soundwave out of bass guitar and flute?
A
Bass guitar
2
Q
What frequency is one octave higher than 440Hz?
A
880Hz
3
Q
Which digital audio resolution has the wider dynamic range: 16 bit or 24 bit?
A
24 bit
4
Q
What is the maximum dynamic range of a 12 bit digital audio resolution?
A
72 bit
5
Q
What is the maximum dynamic range of a 20 bit dynamic audio resolution?
A
120 bit
6
Q
What does the term ‘Kbps’ mean?
A
Kilobytes per second
7
Q
How many samples per second are required for CD quality audio?
A
44.1kHz
8
Q
Which digital audio format uses compression?
A
MP3
9
Q
Explain the DAW process of ‘time compression’
A
Decreasing the length or speeding up the audio without affecting the pitch
10
Q
Why is audio sometimes ‘choppy’?
A
Transfer speed or access speed of the USB is insufficient
11
Q
The SPL is measured at 10 metres from a constant sound source and is found to be 60dB. What would the SPL be at 20 metres from the same sound source?
A
54dB
12
Q
What is the function of the insert?
A
To allow access to the signal path before the EQ section
13
Q
What is the function of the input sens (gain)?
A
To adjust the amplitude of the main mix
14
Q
What is the function of the aux pre?
A
To hear the sound before it reaches the main mix
15
Q
What is the function of aux post?
A
To hear the sound after it is sent to the main mix
16
Q
What is the function of assign 1-2?
A
To send the channel output to buses 1 and 2
17
Q
What is the function of a HPF?
A
Allows high frequencies to pass through
Removes unwanted bass frequencies
Removes plosives
Gives a clearer vocal sound
18
Q
What is the function of LF Freq?
A
To select the frequency below which signal can be boost or cut
19
Q
What kind of cable can carry phantom power?
A
A balanced cable
20
Q
What does the term S/PDIF stand for?
A
Sony Phillips Digital Interface
21
Q
How many channels of audio does a standard S/PDIF cable carry?
A
2
22
Q
What voltage does a standard GPO (general power outlet) provide?
A
220-240V
23
Q
What is the maximum current that can be drawn from a standard GPO?
A
10A
24
Q
What is the maximum power that a standard GPO can provide?
A
2400 watts
25
Describe a method for tuning or equalising a PA system
Feed pink noise through the PA. Use a microphone and spectrum analyser while adjusting the front of house graphic to achieve a flat response
26
What does the term RT60 mean?
The time taken for a sound to fall 60dB below its original intensity
27
What does SPL stand for?
Sound pressure level
28
If you double the distance, how much does the SPL drop?
6dB
29
What is the implication of using a 5A fuse instead of a 2A fuse?
The fuse will let more electricity into the system and could potentially blow the speakers or the electronics inside the amplifier
30
Name two kinds of EQ
Selectable frequency EQ
| Parametric EQ
31
Name two kinds of other EQ
Graphic EQ
Notch filter
Band pass filter
32
What are the characteristics of a notch filter?
A notch filter is very specific and is often used on set in TV and film to get rid of select frequencies
33
Define Parametric EQ
Multi band variable EQ which adjusts the amplitude, frequency and bandwidth (or Q)
34
Define Graphic EQ
Allows levels to be boost or cut at a series of evenly spaced out frequencies
35
What is Graphic EQ used for?
To tune the room, to help control phase cancellation and to get rid of resonant frequencies in the control room
36
Define the ratio of compression
How hard or how much you compress a sound
37
What does ADSR stand for?
Attack, decay, sustain, release
38
Define the term 'threshold'
The level at which an effect begins to work
39
What is the frequency range of the human ear?
20Hz - 20kHz
40
What is the fundamental range on a four string bass?
41Hz - 260Hz
41
Describe the following editing function: Normalise
The loudest peak in volume is detected, and the volume of the entire file is increased to maximum without clipping the peak
42
Describe the following editing function: cross fade
To fade out one sound whilst fading another in
43
Describe the difference between gain and volume
Gain is the amount of signal being passed through whereas volume is how loud a sound is in regards to a person's perception of hearing
44
List two devices you would connect to auxiliaries
Foldback
| Graphic EQ
45
What is the difference between a graphic and parametric equaliser?
Graphic EQ can be adjusted at fixed frequencies whereas parametric EQ can be adjusted at variable frequencies/width
46
What is phantom power and when is it required?
48V dC power which is required for condenser microphones and DI boxes, and is supplied at the microphone preamp or from an external power source
47
Where would you connect an external compressor unit to a mixing console?
At the insert point
48
How does an enabled PRE fade switch on a mixing console affect an auxiliary unit?
The signal is sent to the unit independent of the fader
49
Describe the difference between a balanced and an unbalanced connector
Balanced signals can cancel out inducted interference. The difference is the number of connections - unbalanced connectors have in phase and earth. Balanced connectors have in phase/out of phase earth.
50
What is the function of a crossover?
It divides an audio signal into separate frequency ranges, for example, low, mid, high
51
Describe the difference between an active and a passive speaker sound system
An active system is powered within the unit. Passive systems need an additional power amp.
52
Describe the following term: watts
A measurement of power output
53
Describe the following term: ohms
A measurement of resistance
54
If two signals mixing the same source are out of phase, what is the effect on the sound and how is this caused?
The result is phase cancellation, which is caused by identical wavelengths. Modulation could occur.
55
0 decibels SPL is commonly known as the threshold of:
Hearing
56
120-130 decibels SPL is commonly known as the threshold of:
Pain
57
What is the musical interval between the frequencies 300Hz and 600Hz?
One octave
58
What is the function of Pin 1 on a typical XLR connector?
It is the Earth pin
59
Explain why it is not advisable to use instrument cables to connect power amplifiers and speakers together
Because the cables have the wrong impedance
60
Two types of broadband noise are commonly used as calibration tools in audio production and sound reinforcement. They are named after colours. What are they known as?
White and pink noise
61
Provide two different uses for TRS connectors in audio production
To connect an insert or a stereo signal
62
List three tasks you would perform when normalising a mixing console
Turn down auxiliaries, turn down faders and turn off phantom power
63
What is a common name for the technique of removing the excess time and noise in a recording?
Trim
64
What is the function of phase reverse?
It reverses the phase of channel
65
Provide two audio file formats that employ data compression that you could use to encode a song
MP3, MP4, M4a, AAC, wmv
66
What happens to a signal when we 'attenuate' it?
The volume is reduced
67
When turning off the power to a PA system or a recording studio control room, what piece of audio equipment is usually powered off first?
The power amplifier
68
What is one potential disadvantage of performing a mixdown with a speaker system that incorporates a subwoofer that has not been correctly calibrated?
Results in an uneven mix
69
Give the full name of USB and DVD
Universal Serial Bus and Digital Video Disc
70
List four different tests that would normally be performed when checking electrical and studio equipment and cabling for correct operation and Occupational Health and Safety, such as in a 'test and tag' procedure.
Check for earth loops, check the insulation, measure the voltage and check the solder points
71
Explain 'dynamic range' in relation to audio terminology
Dynamic range refers to the range in volume, low to high, of a person's hearing
72
What is the maximum dynamic range in decibels for the following quantisation resolutions? 16 bit and 24 bit
96dB and 144dB
73
Give two reasons why it is possible to distinguish between the same note played on a clarinet and on a piano
Because they have the same harmonic content and amplitude
74
Which microphone is more directional, cardioid or hyper-cardioid?
Hyper-cardioid
75
Explain the function of the following parameter of a delay unit: Mix
To balance the wet/dry
76
Explain the function of the following parameter of a delay unit: Feedback or regeneration
The number of repeats
77
Explain the term 'non-destructive editing'
Edits exist in instructions for playing back audio files, but the original audio files are not altered
78
Explain why a DI box would normally be used to connect the output of a synthesizer to the stage box of a PA system
To match the impedance
79
Name one kind of filter
High pass filter
80
What is the most directional frequency range in a sound reinforcement system?
Treble or high
81
Explain the function of the gain/trim/input sensitivity potentiometer
To adjust the amount of signal being received
82
List four OH&S checks that you might make when setting up for a gig
Check that all leads are taped down
Check that all equipment is functioning
Check that there is no liquid near the electrical equipment
Check that all leads are tagged
83
Why would you used a DI box to run a signal over a long distance?
Because it ensures that the cable is balanced
84
Explain why you should not use a speaker lead to connect a guitar to an amplifier
Because of the different impedance levels
85
John has plugged an active DI box into a PA line that is working. There is no sound coming from the DI box. The guitar is plugged in correctly and her guitar lead is working. Identify the likely cause of this problem.
No phantom power
86
Explain the importance of the earth pin on a 240 V plug.
It earths the equipment, making it safe
87
In digital recording, what does a real-time plug in do?
It processes audio as it plays (in real time)
88
What is a scratch/guide track?
A rough track used for other instruments when recording
89
What is a mixdown?
A final mix of all tracks and effects etc, to a two-track master
90
Why is it advisable to switch off phantom power when you are not using it?
To avoid clicks and pops when repatching (live) inputs
91
What is the typical application of phase reversal?
To put Mics back in phase
92
What is the typical application of 1-2 button (sub-group send)?
Used, for example, to send drums to a separate sub mix
93
What is the function of the HF-Freq?
Used to boost or cut sibilance
94
What is the human hearing range?
20Hz-2kHz
95
Name a modulation effect
Chorus
Flanger
Phaser
96
Name a dynamic filter
Compression
Gate
Expander
Limiter
97
Name a parameter of a modulation effect
Depth
Wet/Dry
Rate
Gain
98
Name a parameter of a delay effect
```
Delay time
Feedback
Repetitions time
Number of repeats
Gain
Decay
```
99
Name a parameter of a reverb effect
Decay
Reverb time
Pre-delay
Room size
100
What does 'Q' stand for?
Quality or bandwidth
101
What does RMS stand for?
Root, mean, square
102
What is the Inverse Square Law?
```
Double acoustic power = double the decay
If you double the distance, the SPL drops 6dB
P= K
-
D2
```
103
Why should you turn off the speaker before the desk?
Turning off the speaker = turning off the amplifier in the powered speaker
104
Give two basic safety checks that you would perform before using a power lead to set up a sound system
Check that leads are tagged
| Feel the cable for nicks and cuts
105
An iPod or mini jack plug would be correctly identified as:
A 3.5mm stereo jack
106
How is recording quality improved when you record at the highest bit depth possible?
Greater dynamic range
107
What is the highest frequency that can be accurately recorded when sampling at 96kHz?
48Hz
108
What is the name given to the relationship between a high frequency and its safe sampling rate?
Nyquist
109
Give two reasons why audio power cables and dimmed-lighting power cables should be kept separate
To avoid:
Overload of a circuit
Leads overheating
110
If you had to use an instrument microphone for vocals, what equalisation adjustments would need to be made at the mixing desk? Give two examples
Roll of bass
| Cut lows/boost highs
111
Why would you always ensure that your FOH mixing desk is plugged into the same power circuit as all stage audio power?
To avoid 50Hz hum
112
In digital audio records, what does the term 'latency' refer to?
Lag between input and output
113
What is the most directional frequency band?
Highs
114
What are two ways of dealing with latency issues without updating any computer equipment?
Reduce plugins
| Decrease buffer size
115
What is the storage size of a CD-R?
700MB
116
What is the storage size of a DVD-R?
4.7GB
117
If a compressor's ratio is set to 100:1, what is this commonly called?
Limiter/limiting
118
If you are bouncing a multitrack session in a Digital Audio Workstation (DAW), what format is suitable for burning to an audio CD?
- Mono
- Split stereo left/right
- Stereo interleaved
- Dolby AC3
Stereo interleaved
119
What is the difference between split stereo left/right and stereo interleaved?
Split stereo is two files on two tracks as opposed to stereo interleaved which is two files on one track
120
Given the two sounds below, which would produce a sound with the shorter wavelength?
- Thunder
- Umpire/sports whistle
Umpire/sports whistle
121
What is the quantisation resolution, in bits, of audio CD?
16 bits
122
What is the dynamic range, in decibels (dB), of 8 bit audio?
48dB (8x6)
123
Explain the function of a noise gate when applied to an audio signal
It removes unwanted noise or microphone spill from an audio channel. It works by setting a threshold. When audio goes below the threshold the gate ‘closes’ and the audio is muted. When audio goes above the threshold the gate ‘opens’ and the audio is heard.
124
Provide a practical application of effective use of a noise gate in a recording situation
Removing microphone spill in a recording/track, removing noise/buzz/hum from a recording/track, or making sounds tighter/shorter to improve clarity in a mix.
Eg. Cleaning up spill on a snare drum
125
Two speakers of 4 ohms impedance are wired in series. Calculate the impedance.
(4 + 4) = 8 ohms
126
Two speakers of 4 ohms impedance are wired in parallel. Calculate the total impedance.
(1/4 + 1/4 = 2/4) = 2 ohms impedance
127
What voltage does an Australian 3-phase power outlet provide?
415 volts
128
What is the alternating frequency of Australian AC mains electricity?
50 Hz
129
Name two essential functions the earth pin provides when connecting audio equipment to AC mains electricity
Any two of the following:
- Prevents hum/buzz/noise
- Ensures the safety of the user
- Ensures protection of equipment
130
Describe the function of a 3-way crossover
It divides the audio signal into low, mid and high frequency ranges, because different speakers are used for each frequency range.
Low - Sub
Mid - Woofer
High - Horns
131
In a live mixing setup, what type of auxiliary send is typically used for outboard fx?
Post (fader) aux
132
In a live mixing setup, what type of auxiliary send is typically used for foldback?
Pre (fader) auxiliary
133
What is the speed of sound in air at 20°C?
343 metres per second
134
An imported audio file in a Digital Audio Workstation (DAW) plays back at a faster speed than expected.
a) Provide a possible reason that could cause this to occur.
b) Give two solutions to avoid this problem
a) Incorrect sample rate
b) - Convert the sample rate of the imported file to match the DAW
- Change the sample rate of the DAW to match the imported file
135
At what frequency does a High Pass Filter begin to work at?
80Hz
136
What is the function of pan?
It places the sound in a stereo field
137
What could pre fader listen be used for?
A line check
138
What are the parameters of parametric EQ?
- Boost/Cut
- Frequency
- Q (Quality or Bandwidth)
139
A snare drum playing in a room causes reverberation. What three components of the sound would be heard by a listener in the room?
Component 1 - Direct
Component 2 - Early reflections
Component 3 - Late reflections
140
What does RT60 mean in relation to reverb?
The time taken for reverb to drop in volume by 60 dB
141
Identify two reasons for tuning or equalising a public address (PA) system installed in a room
1 - To obtain the maximum gain before feedback across the frequency spectrum
2 - To reduce the effects that room resonance might have on the tonal quality of sounds amplified by the public address system
142
Explain why a direction injection (DI) box would normally be used to connect the output of a synthesiser to the stage box of a PA system?
To match the impedance caused by the different output levels
143
An acoustic guitar is being recorded with two microphones positioned at different distances. What problem might occur if the two signals from the microphones were mixed together?
Phase cancellation (at certain frequencies)
144
The pitch of wind and stringed instruments changes with temperature. As the temperature increases, does the pitch rise or fall? Explain why.
Wind instruments - Rise, because the speed of sound increases with air temperature
Stringed instruments - Fall, because the strings expand as the temperature increases
145
What is the function of auxiliary pre?
It sends levels independent of the fader
146
What is the function of auxiliary post?
It sends levels dependant on the channel fader
147
Describe the following editing function:
| The scrub tool
Dragging the mouse pointer across the waveform display plays the audio at a variable speed and direction
148
What common PA system component produces phantom power?
Mixing desk
149
List three differences between an active and a passive 2-way speaker system
1 - Active requires mains power and passive does not
2 - Active has crossover before amps and passive has crossover after the amplifier
3 - Active has amplifiers built in and passive requires external amplification
150
If you were to process a kick drum with a compressor and a gate, which device should the signal pass through first? Explain why.
The gate, because it requires a wider dynamic range to operate effectively. Compressing the signal first would reduce the dynamic range, making it difficult for the gate to operate.
151
What is the speed of sound in air at 20°C?
343 metres per second
152
What is bit depth?
The about of divisions that the amplitude can quantise to
153
What is sample rate?
The amount of samples taken per second
154
MIDI
Musical instrument digital interface
155
What is AIFF?
Audio interchange file format - Standard data format
