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Odisha CHSE +2 Vocational Audio Video Technique study materials
Odisha CHSE +2 Vocational Audio Video Technique study resources

Odisha CHSE +2 Vocational Audio Video Technique practice questions

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Question 1Fundamentals of Sound, Acoustics and Hearing

In audio work, sound is best described as which of the following?

  1. a longitudinal mechanical wave that needs a material medium Correct answer.
  2. a continuous stream of charged particles emitted by a vibrating body
  3. a transverse wave that can travel without any medium
  4. an electromagnetic wave that travels through a vacuum

Explanation

Sound is a mechanical disturbance in which a vibrating source produces compressions and rarefactions that pass through a material medium as a longitudinal wave. Because it depends on particle motion, sound cannot propagate through a vacuum.

Question 2Fundamentals of Sound, Acoustics and Hearing

A 200 Hz tone is changed to 400 Hz while its amplitude is held constant. A listener mainly perceives which change?

  1. a slower speed of sound
  2. a fall in loudness
  3. a rise in pitch Correct answer.
  4. a change in timbre only

Explanation

Pitch is the subjective sensation most closely related to frequency, so raising frequency from 200 Hz to 400 Hz raises the pitch by about one octave. Loudness relates mainly to amplitude, and the speed of sound depends on the medium rather than on the source frequency.

Question 3Fundamentals of Sound, Acoustics and Hearing

For a pure tone, increasing the waveform amplitude while keeping the frequency fixed mainly raises which attribute?

  1. the wavelength in air
  2. the perceived loudness Correct answer.
  3. the speed of propagation
  4. the pitch of the tone

Explanation

Amplitude corresponds to the magnitude of pressure variation and therefore to sound intensity, which listeners experience as loudness. Frequency governs pitch, while wavelength and propagation speed are not increased simply by making the waveform taller.

Question 4Fundamentals of Sound, Acoustics and Hearing

A sound wave passes from air into water. What happens to its speed?

  1. It increases because water is acoustically stiffer Correct answer.
  2. It stays exactly the same because the frequency does not change
  3. It decreases because water is much denser than air
  4. It falls to zero because water reflects all sound

Explanation

Sound speed in a medium depends on elastic stiffness and density, and water's much greater bulk modulus outweighs its higher density. As a result, sound travels at roughly 1,500 m/s in water compared with about 340 m/s in air, although the frequency stays unchanged and the wavelength changes.

Question 5Fundamentals of Sound, Acoustics and Hearing

A 1 kHz tone travels through air at 340 m/s. What is its wavelength?

  1. 340 m
  2. 0.34 m Correct answer.
  3. 34 m
  4. 3.4 m

Explanation

The wave relationship is wavelength equals speed divided by frequency. Here 340 m/s divided by 1,000 Hz gives 0.34 m, which is a typical wavelength for a mid-frequency sound in air.

Question 6Fundamentals of Sound, Acoustics and Hearing

The frequency range normally audible to a healthy young human ear is about which of the following?

  1. 2 Hz to 2 kHz
  2. 200 Hz to 200 kHz
  3. 20 Hz to 20 kHz Correct answer.
  4. 20 kHz to 200 kHz

Explanation

Normal human hearing extends from about 20 Hz at the low end to about 20 kHz at the high end, although sensitivity falls near both limits. Frequencies above 20 kHz are ultrasound, and very low frequencies below 20 Hz are infrasound.

Question 7Fundamentals of Sound, Acoustics and Hearing

A sound's intensity level rises by 10 dB. What change in sound intensity does this represent?

  1. a tenfold increase in sound intensity Correct answer.
  2. a doubling of sound intensity
  3. a hundredfold increase in sound intensity
  4. no change in sound intensity

Explanation

For intensity level in decibels, the formula is 10 log base 10 of the intensity ratio. A 10 dB increase therefore means the intensity ratio is 10, while a 20 dB increase would mean a hundredfold increase.

Question 8Fundamentals of Sound, Acoustics and Hearing

A flute and a violin play notes of the same pitch and loudness, yet they sound different. This is chiefly because the two instruments differ in which respect?

  1. the exact value of their fundamental frequency
  2. their harmonic spectrum and envelope Correct answer.
  3. the measured sound pressure level of each note
  4. the speed of sound through the concert hall

Explanation

Timbre is what distinguishes instruments sounding at the same pitch and loudness, and it depends on the number and relative strength of harmonics plus the attack and decay envelope. The fundamental frequency and overall level are deliberately matched in the question, so they cannot explain the difference.

Question 9Fundamentals of Sound, Acoustics and Hearing

A room has an excessively long reverberation time. Which action is most directly effective in reducing it?

  1. raise the electrical drive level of the source
  2. move the loudspeakers closer together
  3. fit sound-absorbing material to surfaces Correct answer.
  4. increase the internal air volume of the room

Explanation

Reverberation time depends mainly on room volume and the total absorption present. Adding absorptive treatment reduces reflected sound energy and therefore shortens the decay, whereas enlarging the room generally lengthens reverberation and moving or driving the loudspeakers does not change the room's absorption.

Question 10Fundamentals of Sound, Acoustics and Hearing

A loud low-frequency sound makes a softer high-frequency sound much harder to hear, while the high-frequency sound masks the low-frequency one far less. This asymmetry is called which phenomenon?

  1. downward spread of masking
  2. the precedence effect
  3. upward spread of masking Correct answer.
  4. the Doppler effect

Explanation

Masking is generally stronger when the masker lies below the frequency of the masked sound, because excitation spreads upward along the basilar membrane. This asymmetry is called the upward spread of masking and is important when judging speech intelligibility and mix clarity.

Question 11Fundamentals of Sound, Acoustics and Hearing

In sound level measurements, the 0 dB reference for sound pressure level (SPL) is defined as which pressure?

  1. 20 µPa Correct answer.
  2. 200 µPa
  3. 1 Pa
  4. 0.02 Pa

Explanation

By international convention, 0 dB SPL is set at 20 µPa (2 × 10⁻⁵ Pa), which is roughly the threshold of hearing for a 1 kHz tone. SPL in decibels is calculated as 20 log₁₀(p / 20 µPa), so every calibration of a sound level meter is traceable to this reference.

Question 12Fundamentals of Sound, Acoustics and Hearing

The frequency interval from 250 Hz to 500 Hz is correctly described as which of the following?

  1. one semitone
  2. a decade
  3. one third-octave
  4. one octave Correct answer.

Explanation

An octave is defined by a 2:1 frequency ratio, and 500 Hz is exactly twice 250 Hz, so the interval is one octave. This doubling rule is used constantly in audio work, for example when reading filter and equaliser scales.

Question 13Fundamentals of Sound, Acoustics and Hearing

A small loudspeaker radiates uniformly in all directions in a free field. A listener moves from 2 m to 4 m away from it. The sound pressure level at the new position falls by approximately which amount?

  1. 6 dB Correct answer.
  2. 0 dB
  3. 3 dB
  4. 12 dB

Explanation

A point source spreads its acoustic power over a spherical area that grows with the square of distance, so doubling the distance quarters the intensity. A factor of four in intensity equals 10 log₁₀ 4 ≈ 6 dB, which is the familiar inverse-square rule used when placing microphones and speakers.

Question 14Fundamentals of Sound, Acoustics and Hearing

A pure tone has a frequency of 500 Hz. One complete cycle of its waveform lasts for which duration?

  1. 20 ms
  2. 0.5 ms
  3. 2 ms Correct answer.
  4. 500 ms

Explanation

The period is the reciprocal of frequency, so T = 1/f = 1/500 s = 0.002 s, which is 2 ms. Knowing this lets an engineer predict how a waveform lines up with a delay, a sample clock or a room reflection.

Question 15Fundamentals of Sound, Acoustics and Hearing

In air at about 343 m/s, a room warms up by 10 °C while humidity and pressure stay effectively unchanged. The speed of sound in that air:

  1. stays exactly the same
  2. rises by about 60 m/s
  3. falls by about 6 m/s
  4. rises by about 6 m/s Correct answer.

Explanation

For air the approximation c ≈ 331 + 0.6·T m/s holds, where T is in degrees Celsius, so a 10 °C rise adds roughly 6 m/s, about 1.8 percent. This matters in practice because delay-based calculations and room-mode predictions shift slightly as a studio or hall warms up.

Question 16Fundamentals of Sound, Acoustics and Hearing

The main acoustic function of the middle-ear ossicles, the malleus, incus and stapes, is to:

  1. reflect low-frequency sound back out of the ear canal
  2. convert sound energy into electrical nerve impulses in the cochlea
  3. block all frequencies above about 1 kHz from reaching the inner ear
  4. match air impedance to cochlear fluid impedance Correct answer.

Explanation

Air has a low characteristic impedance while the fluid of the cochlea has a much higher one, so most sound would simply reflect at the oval window. The area ratio between the tympanic membrane and the stapes footplate, together with the lever action of the ossicles, provides roughly 20 to 25 dB of pressure gain and allows efficient energy transfer into the inner ear.

Question 17Fundamentals of Sound, Acoustics and Hearing

Within the cochlea, high-frequency tones excite hair cells mainly at which location?

  1. near the base, where the basilar membrane is narrow and stiff Correct answer.
  2. in the semicircular canals, which respond to high tones
  3. at the apex, where the basilar membrane is widest and most flexible
  4. uniformly along the whole length of the basilar membrane

Explanation

The basilar membrane is narrow and stiff at the base and wide and floppy at the apex, so it behaves like a bank of mechanical filters. High frequencies produce maximum vibration near the base and low frequencies near the apex, forming the tonotopic map that underlies place coding of pitch.

Question 18Fundamentals of Sound, Acoustics and Hearing

Two sine tones of 440 Hz and 444 Hz are played together at equal level. A listener perceives a slow fluctuation in loudness at which rate?

  1. 444 Hz
  2. 4 Hz Correct answer.
  3. 2 Hz
  4. 884 Hz

Explanation

The two waves repeatedly drift into and out of phase, so they alternately reinforce and cancel, giving an amplitude beat whose rate equals the difference of the two frequencies, |444 − 440| = 4 Hz. This is the same phenomenon a piano tuner listens for when matching strings.

Question 19Fundamentals of Sound, Acoustics and Hearing

A direct signal is summed with an identical copy delayed by 1 ms. Assuming equal levels, the first frequency at which the two copies cancel is approximately:

  1. 500 Hz Correct answer.
  2. 250 Hz
  3. 2000 Hz
  4. 1000 Hz

Explanation

Cancellation occurs when the delay equals half a period, that is when 1 ms corresponds to 180° of phase shift. Solving f = 1/(2 × 0.001 s) gives 500 Hz, and further nulls appear at odd multiples of that frequency, 1500 Hz, 2500 Hz and so on, while even multiples reinforce.

Question 20Fundamentals of Sound, Acoustics and Hearing

A sound level meter is set to A-weighting, displayed as dBA, because this weighting:

  1. removes the effect of room reverberation from the measured value
  2. boosts low frequencies to compensate for the limited low-frequency response of measurement microphones
  3. displays only the peak level of impulsive sounds such as gunshots and hammer blows
  4. attenuates low and some high frequencies to approximate the ear's sensitivity at moderate levels Correct answer.

Explanation

A-weighting follows the 40-phon equal-loudness contour: it rolls off low frequencies heavily and high frequencies slightly, so the reading tracks subjective loudness of moderate-level sound. It is the standard weighting for hearing-conservation limits and environmental noise rules, which is why exposure figures are usually quoted in dBA.

Question 21Fundamentals of Sound, Acoustics and Hearing

A worker claps once in a large hall and hears a distinct echo 0.20 s later. Taking the speed of sound in air as 340 m/s, what is the distance from the worker to the reflecting wall?

  1. 340 m
  2. 17 m
  3. 68 m
  4. 34 m Correct answer.

Explanation

The sound travels to the wall and back, so the total path length is v × t = 340 × 0.20 = 68 m. The one-way distance to the wall is half of that total path, which is 34 m.

Question 22Fundamentals of Sound, Acoustics and Hearing

At a low sound pressure level, a 100 Hz tone and a 1 kHz tone are set to the same sound pressure level. On the basis of equal-loudness contours, how will a typical listener perceive them?

  1. The 1 kHz tone will sound louder than the 100 Hz tone. Correct answer.
  2. Both tones will sound equally loud at every level.
  3. The 100 Hz tone will be inaudible while the 1 kHz tone is clear.
  4. The 100 Hz tone will sound louder than the 1 kHz tone.

Explanation

Equal-loudness contours show that human hearing is less sensitive at low frequencies, particularly at low sound pressure levels. Therefore, at the same SPL, a 1 kHz tone is normally perceived as louder than a 100 Hz tone.

Question 23Fundamentals of Sound, Acoustics and Hearing

Two independent loudspeakers each produce a sound pressure level of 70 dB at the same listener position. Their sounds are uncorrelated. What is the approximate combined sound pressure level at that position?

  1. 70 dB
  2. 73 dB Correct answer.
  3. 140 dB
  4. 76 dB

Explanation

For uncorrelated sources of equal level, the sound intensities add, and doubling the intensity raises the level by about 3 dB. Thus two 70 dB sources give approximately 73 dB, not a simple arithmetic sum of decibels.

Question 24Fundamentals of Sound, Acoustics and Hearing

In a rectangular room, the lowest axial standing-wave mode between two opposite walls is determined primarily by which factor?

  1. Wall spacing and boundary type Correct answer.
  2. Total wall area alone
  3. Room volume alone
  4. Average absorption alone

Explanation

Axial room modes are standing waves between opposite surfaces, so their frequencies depend on the separation between those surfaces and on the boundary conditions at the walls. Volume and absorption affect modal density and decay rather than directly setting the axial mode spacing.

Question 25Audio Recording Equipment, Microphones and Mixing

A condenser microphone connected to a mixing console needs its standard phantom supply. What voltage and connector convention does the console provide?

  1. 24 V AC on pins 2 and 3 with return on pin 1
  2. 110 V AC on pin 1 with return on pin 2
  3. 48 V DC on pins 2 and 3, return pin 1 Correct answer.
  4. 12 V DC on the shell with no signal return

Explanation

Standard phantom power is +48 V DC, applied equally to XLR pins 2 and 3 with the return on pin 1. It powers the condenser's internal preamplifier and polarises the capsule; the equal voltage on both signal pins keeps the audio path balanced.

Question 26Audio Recording Equipment, Microphones and Mixing

A rock vocalist sings extremely loudly within a few centimetres of the grille. Which microphone type is the safest first choice for this job?

  1. Moving-coil dynamic microphone Correct answer.
  2. Electret condenser microphone
  3. Large-diaphragm condenser microphone
  4. Ribbon microphone without a blast filter

Explanation

A moving-coil dynamic microphone handles high sound pressure levels and needs no phantom power, so it tolerates close, loud vocals. Condensers are more sensitive and ribbons are fragile, making them less suitable without extra protection.

Question 27Audio Recording Equipment, Microphones and Mixing

Which connector is the standard choice for a balanced microphone cable running mic-level audio to a console input?

  1. RCA phono plug
  2. 3.5 mm mono plug
  3. TS 6.35 mm jack
  4. XLR connector Correct answer.

Explanation

The XLR connector is the standard for balanced microphone lines because it carries two signal conductors plus a shield and locks into place. Its three-pin wiring supports differential transmission, which rejects noise on long mic cables.

Question 28Audio Recording Equipment, Microphones and Mixing

Two performers face each other on opposite sides of one microphone, and the audience is at the sides. Which polar pattern picks up both performers while rejecting the audience most strongly?

  1. Cardioid
  2. Omnidirectional
  3. Hypercardioid
  4. Figure-eight Correct answer.

Explanation

A figure-eight, or bidirectional, pattern has two lobes facing the front and rear of the capsule and a deep null at the sides. Placing the performers in those lobes therefore captures both voices while the side audience falls into the null.

Question 29Audio Recording Equipment, Microphones and Mixing

At soundcheck a channel fader sits at unity, but its meter peaks only around -20 dBFS. What is the best first adjustment to improve gain staging?

  1. Increase the channel input gain (trim) Correct answer.
  2. Push the fader far above unity
  3. Engage the input pad
  4. Insert a compressor and lower its threshold

Explanation

The input gain sets the level entering the channel, so raising it brings the signal into a healthy range before the fader and mix processing. This preserves headroom downstream and avoids forcing the fader above unity.

Question 30Audio Recording Equipment, Microphones and Mixing

A keyboard has an unbalanced high-impedance output and must feed a mixer 15 metres away. Which device best matches the signal and prevents hum pickup?

  1. Graphic equaliser
  2. DI box Correct answer.
  3. Microphone preamplifier
  4. Compressor

Explanation

A DI box converts an unbalanced high-impedance instrument signal into a balanced low-impedance line that can travel long distances without picking up noise. It also provides ground isolation, which helps break hum loops.

Question 31Audio Recording Equipment, Microphones and Mixing

A monitor engineer wants a singer's stage wedge mix to stay the same when the front-of-house engineer moves the channel fader. Which console send should be used?

  1. Master bus output
  2. Post-fader auxiliary send
  3. Pre-fader auxiliary send Correct answer.
  4. Group bus output

Explanation

A pre-fader aux send takes signal from the channel before the fader, so house fader changes do not alter the monitor mix. Post-fader sends follow fader movement and are used for effects such as reverb.

Question 32Audio Recording Equipment, Microphones and Mixing

A cardioid microphone used very close to a voice sounds excessively boomy. What is this effect and what is a practical remedy?

  1. Phantom overload; disable the 48 V supply
  2. Proximity effect; back off, use low-cut Correct answer.
  3. Off-axis colouration; rotate the capsule
  4. Comb filtering; insert a short delay line

Explanation

Directional microphones exhibit proximity effect, a boost in low frequencies as the source moves closer to the capsule. Moving the performer back or engaging a high-pass filter reduces the boominess while keeping the cardioid rejection.

Question 33Audio Recording Equipment, Microphones and Mixing

A long microphone cable runs beside a dimmer rack and picks up hum. Which transmission method best rejects this induced noise?

  1. Optical cable with an analogue adapter plug
  2. Single-conductor cable returning through earth
  3. Balanced twisted pair to differential input Correct answer.
  4. Unbalanced coaxial cable with a heavy shield

Explanation

A balanced twisted pair carries the signal as two equal but opposite voltages, and the differential input amplifies the difference while rejecting noise common to both conductors. Twisting also helps ensure induced noise appears equally on both wires.

Question 34Audio Recording Equipment, Microphones and Mixing

A compressor with a very fast attack softens the initial click of a kick drum. Which setting change restores the attack while still controlling the sustain?

  1. Lengthen the attack time Correct answer.
  2. Set the ratio to 1:1
  3. Raise the threshold only
  4. Shorten the release time

Explanation

A longer attack lets the initial transient pass through uncompressed before gain reduction begins, preserving the kick's click. The compressor then acts on the sustain that follows.

Question 35Audio Recording Equipment, Microphones and Mixing

Which principle produces the electrical output of a moving-coil dynamic microphone?

  1. Electromagnetic induction in a coil moving inside a magnetic field Correct answer.
  2. Capacitance change between a fixed backplate and a diaphragm
  3. Resistance change in carbon granules compressed by sound
  4. Piezoelectric charge produced when a crystal is bent by sound

Explanation

A moving-coil dynamic microphone works by electromagnetic induction: sound moves a diaphragm attached to a small coil suspended in a magnetic field, and the coil's motion generates a voltage. It does not need an internal amplifier or external phantom power. Condenser, piezoelectric and carbon designs use different physical principles.

Question 36Audio Recording Equipment, Microphones and Mixing

On a mixing console channel, what does the pan control set?

  1. The channel's position between the left and right main outputs Correct answer.
  2. The threshold at which the channel compressor starts working
  3. The number of auxiliary sends feeding the monitor mix
  4. The input gain applied before the channel fader

Explanation

The pan control places the channel's signal in the stereo field between the left and right main outputs. It does not change input gain, auxiliary send quantities or compressor behaviour. Panning is normally applied after the channel fader in the signal path.

Question 37Audio Recording Equipment, Microphones and Mixing

What is the main purpose of a pop filter placed between a vocalist and a microphone?

  1. It removes low-frequency room rumble from the signal
  2. It reduces the air blast from plosive sounds reaching the capsule Correct answer.
  3. It isolates the microphone stand from floor vibrations
  4. It increases the microphone's sensitivity to quiet singing

Explanation

A pop filter breaks up the concentrated air blast produced by plosive consonants such as p and b before it reaches the capsule. This reduces sudden diaphragm movement and the resulting low-frequency thump. It is not an acoustic isolator or a sensitivity booster.

Question 38Audio Recording Equipment, Microphones and Mixing

A microphone with an output impedance of 200 Ω is connected to a mixer input of 2 kΩ. Why is this impedance relationship desirable?

  1. It lets the input receive most of the mic voltage without loading it Correct answer.
  2. It allows phantom power to pass to the microphone without any loss
  3. It doubles the signal voltage and adds a fixed 6 dB of gain
  4. It makes the microphone cable immune to all radio interference

Explanation

For voltage transfer, a microphone input should present an impedance many times higher than the source impedance, commonly at least ten times. With 200 Ω feeding 2 kΩ, the input is about ten times the source, so the microphone is only lightly loaded and most of its voltage appears at the input. This is called bridging and avoids loss of level and low-frequency response.

Question 39Audio Recording Equipment, Microphones and Mixing

A lecturer speaks while moving a little to each side of a single microphone, and the audience sits behind the microphone. Which polar pattern is the best choice?

  1. Figure-of-eight
  2. Omnidirectional
  3. Hypercardioid
  4. Cardioid Correct answer.

Explanation

A cardioid pattern is most sensitive at the front and has a null at the rear, so it picks up the lecturer while rejecting much of the audience behind the microphone. Its front pickup is also wide enough to tolerate small side-to-side movement. Omnidirectional and figure-of-eight patterns would pick up more rear sound, and hypercardioid has a rear lobe that would favour the audience.

Question 40Audio Recording Equipment, Microphones and Mixing

To reduce low-frequency rumble and handling noise on a vocal channel while leaving the voice's character mostly unchanged, which channel control is most appropriate?

  1. A high-pass filter set around 80–100 Hz Correct answer.
  2. A narrow boost at 3 kHz
  3. A long reverb with a bright tail
  4. A compressor with a very slow release

Explanation

A high-pass filter removes energy below its corner frequency, so it reduces rumble, handling noise and low-frequency breath sounds. Setting it around 80–100 Hz usually leaves most vocal fundamentals and intelligibility intact. A boost, reverb or slow compressor does not target low-frequency noise.

Question 41Audio Recording Equipment, Microphones and Mixing

When several microphones close-mic different drums in one kit, which practice most reduces phase cancellation between adjacent microphones?

  1. Keep each adjacent microphone at least three times as far from the source as the nearest one Correct answer.
  2. Point every microphone downward at the floor
  3. Set every channel fader to exactly the same level
  4. Switch every microphone to the omnidirectional pattern

Explanation

The 3:1 rule helps control phase cancellation: where practical, a microphone should be at least three times farther from a source it is not intended to pick up than the neighbouring microphone is from its own source. This reduces the level of unwanted bleed and the comb filtering it can cause. Equal faders, omnidirectional patterns or aiming at the floor do not solve the distance relationship.

Question 42Audio Recording Equipment, Microphones and Mixing

Which connector type carries a balanced signal on a single 1/4-inch plug with three contacts?

  1. Speakon connector
  2. RCA phono plug
  3. TRS jack Correct answer.
  4. TS jack

Explanation

A 1/4-inch TRS jack has tip, ring and sleeve contacts, which allow two signal conductors plus a shield, so it can carry a balanced line-level or mic-level signal. A TS jack has only tip and sleeve and is unbalanced. RCA phono and Speakon connectors are not the standard three-contact 1/4-inch balanced option.

Question 43Audio Recording Equipment, Microphones and Mixing

Two identical microphones pick up the same steady sound source from 1 m and 3 m away in a free field. Using the inverse-square law, approximately how much lower is the level at the 3 m microphone?

  1. About 9.5 dB Correct answer.
  2. About 6 dB
  3. About 20 dB
  4. About 3 dB

Explanation

Sound pressure level falls by about 6 dB each time the distance from a point source doubles in a free field. Moving from 1 m to 3 m is a factor of three, and 20 log10(3) is about 9.5 dB. The level at 3 m is therefore roughly 9.5 dB lower, not 3, 6 or 20 dB.

Question 44Audio Recording Equipment, Microphones and Mixing

An engineer engages the -10 dB pad on a condenser microphone while recording a loud snare drum. What is the pad actually doing?

  1. It reduces the signal inside the microphone before the internal preamplifier to prevent overload Correct answer.
  2. It lowers the channel fader by 10 dB after the signal reaches the console
  3. It narrows the polar pattern so less room sound is captured
  4. It adds 10 dB of gain to compensate for a quiet source

Explanation

A pad is an attenuator placed inside the microphone, ahead of its internal preamplifier. Engaging -10 dB reduces the capsule signal by 10 dB so loud sources such as a close snare do not overload the microphone electronics. It is not a console fader move, a polar-pattern change or added gain.

Question 45Audio Recording Equipment, Microphones and Mixing

A microphone datasheet lists a sensitivity of 2 mV/Pa. What does this specification describe?

  1. the highest sound pressure level the microphone can accept before its output distorts
  2. the ratio between on-axis pickup and rear pickup measured at one kilohertz
  3. the frequency at which the microphone's output falls by three decibels
  4. the output voltage the microphone delivers for a sound pressure of one pascal Correct answer.

Explanation

Sensitivity states how much electrical output a microphone produces for a defined acoustic input, normally one pascal (about 94 dB SPL), and is quoted in mV/Pa or dBV/Pa. It tells the engineer how much preamp gain a quiet source will demand before the fader is touched. It says nothing about maximum SPL handling, polar pattern or frequency response, each of which has its own separate specification.

Question 46Audio Recording Equipment, Microphones and Mixing

While treating a ringing tom in a drum overhead pair, an engineer sets a parametric EQ bell to 250 Hz with Q at 10. What does this Q setting produce?

  1. a shelving shape that changes every frequency above 250 Hz
  2. a broad, gentle cut that spreads across several octaves around 250 Hz
  3. a narrow cut affecting only a small band of frequencies around 250 Hz Correct answer.
  4. a fixed high-pass filter that removes all content below 250 Hz

Explanation

Q sets the sharpness of a parametric bell: a high Q gives a narrow bandwidth, so only a small region around the centre frequency is altered. A value of 10 is therefore used surgically to remove a single ringing tone while neighbouring frequencies stay almost untouched. Low Q values produce the wide, gentle contours used for overall tonal shaping rather than problem removal.

Question 47Audio Recording Equipment, Microphones and Mixing

A compressor on a vocal channel is set to a threshold of -20 dBFS and a ratio of 4:1. A phrase peaks at -4 dBFS after the attack and release have settled. How much gain reduction is applied at that peak?

  1. 20 dB
  2. 4 dB
  3. 12 dB Correct answer.
  4. 16 dB

Explanation

The peak sits 16 dB above the threshold, since -4 dBFS minus -20 dBFS equals 16 dB. At a 4:1 ratio only one quarter of that excess passes, so the output rests 4 dB above the threshold and the compressor has removed the remaining 12 dB. Gain reduction is the excess above threshold minus the part allowed through.

Question 48Audio Recording Equipment, Microphones and Mixing

A mixing console feeds a recorder whose unbalanced input is nominally -10 dBV with only about 6 dB of headroom above that. The console's balanced output runs at +4 dBu nominal. Which interface treatment is most appropriate?

  1. add about 14 dB of gain ahead of the recorder to reach its nominal level
  2. raise the console output by 12 dB to overcome the nominal level difference
  3. connect them directly, since both are analogue line-level signals
  4. attenuate the console output by about 12 dB and feed the recorder unbalanced Correct answer.

Explanation

A +4 dBu nominal level is roughly 12 dB (about 11.8 dB) hotter than a -10 dBV nominal level, and the recorder has only 6 dB of headroom, so a direct connection will clip on normal programme peaks. A pad of about 12 dB brings the console's nominal output close to what the recorder expects while keeping the peaks inside its headroom. The balanced-to-unbalanced transition also needs the correct wiring of the cold and screen conductors.

Question 49Fundamentals of Video, Television Signals and Colour Systems

In the 625-line PAL system used for terrestrial television in India, the picture is scanned at:

  1. 25 frames per second, with each frame sent as a single progressive scan
  2. 25 frames per second, with each frame made of two interlaced fields Correct answer.
  3. 50 frames per second, with each frame made of two interlaced fields
  4. 30 frames per second, with each frame made of two interlaced fields

Explanation

PAL in the 625-line broadcast standard runs at 50 fields per second. Two interlaced fields make one complete frame, so the frame rate is 25 frames per second. India's terrestrial television service used this 625/50 PAL arrangement.

Question 50Fundamentals of Video, Television Signals and Colour Systems

The standard-definition television picture in the 625-line system has a display aspect ratio of:

  1. 3:2
  2. 16:9
  3. 5:4
  4. 4:3 Correct answer.

Explanation

Standard-definition television, including the 625-line PAL service, uses a 4:3 frame: four units wide for every three units high. The wider 16:9 shape belongs to widescreen and high-definition services.