First, multiple choice questions
Second, the question and answer questions
Third, the essay questions
First, multiple choice questions (50 points)
1. The “natural†sound only means that the sound level of the playback sound in the hall should be reduced.
A. Low frequency B, intermediate frequency C, high frequency D, full frequency
2. It is better to use ( ) a little reverberation time in a performance venue where sound reinforcement is often used.
A. Short B, long C, very short D, extremely long
3. The reverberation time depends on the room ( ) and the vocal processing.
A. Area B, volume C, length D, width
4. It is possible to improve the language by using a directional speaker ( ).
A. Thickness B, velocity C, sharpness D, fullness
5. Later sound energy will increase ( ).
A. Loudness B, clarity C, stereoscopic D, sense of space
6. The threshold of hearing is determined based on the minimum sound pressure required to produce an impression.
A. Hearing B, visual C, feeling D, loudness
7. The "square" unit only applies to the loudness value determined by ( ).
A. Objective B, subjective C, high frequency D, low frequency
8. The A weighting curve roughly corresponds to the sensitivity of the human ear to the ( ) side.
A. 100 B, 70 C, 40 D, 10
9. The tone recognition requires a slightly longer "specific time period", which is about ( ) ms for the intermediate frequency and high frequency.
A. 50 B, 30 C, 2 D, 4~8
10. The human ear has a minimum or "inherent" reverberation time of approximately () ms.
A. 400 B, 350 C, 200 D, 100
11. The sense of direction below 300 Hz is mainly inferred by propagation ( ).
A. Phase difference B, sound pressure difference C, time difference D, stereoscopic
12. If the two signals arrive at the same time or near at the same time, the phase shift between the two signals reaches ( ), the sound image is not out of position.
A. 360 degrees B, 270 degrees C, 180 degrees D, 90 degrees
13. The decentralized dimension is characterized by the use of a large number of () speakers in close proximity to the listener's seat, which allows for high resolution by eliminating reverberation by direct coverage.
A. Two B, multiple C, arbitrary D, single
14. One of the most important factors influencing the clarity and the sense of openness is to adjust the sound energy of the listener's perceived sound pattern on ( ) and at the location.
A. Time domain B, area C, airspace D, sea
15. Generally, professional-grade equipment has a non-uniformity of less than plus or minus (dB) at the maximum output in the frequency range of 20 Hz to 20 kHz.
A. 10dB B.3dB C.1dB D.6dB
16. The main reason for the dry, partial "hard" pronunciation is that ( ) the excess is increased.
A. 1KHz~15KHz B, 500Hz~5000Hz C, 250Hz D, 15KHz~20KHz
17. The main reason for the sharpness and harshness of the pronunciation is that the hearing fatigue is easy to increase.
A. 800Hz B, 5KHz C, 3400Hz D, 12KHz
18. The sound level of playing disco music in the ballroom is generally 110dB, and its playing time should not exceed () hours.
A. Half B, 1 C, 2 D, 4
19. The frequency with "longitudinal sense" means ( ).
A. 4~6KHz B, 2.5KHz C.500~800Hz D.15KHz
20. Use two microphones to form a symmetrical triangle with the sound source. The ideal position is: the spacing between the two microphones should be ( )m
A. 0.5~1m B.2m C.1.2m D.1.5m
twenty one. Bidirectional microphones have a narrow range of applications and are commonly used in stereo telephony systems.
A. M-SB, A-BC, X-YD, arbitrary
twenty two. When two columns of coherent sound waves with the same waveform propagate in opposite directions of the same line, the superimposed line wave is ( ), which is generally caused by the wall surfaces whose two sides are parallel to each other.
A. Standing wave B, sound wave C, interference wave D, comb wave
twenty three. There are five kinds of frequency weighting: A, B, C, D, and E. The A weighting curve is more suitable for the measurement of low loudness sound field, which is about ( ).
A. 110 B, 70 C, 40 D, 150
twenty four. The diffraction of sound waves is also called ( ).
A. Refraction B, diffraction C, reflection D, transmission
25. The dynamic range of the vocals is approximately ( ) dB.
A. 90 B, 75 C, 35 D, 20
26. In order to ensure that the equipment can work normally under the impact of unexpected large signals, the peak reserve of the power amplifier circuit should be around () dB.
A. 60 B, 40 C, 20 D, 10
27. The IEC268-15 standard states that the line output impedance of all audio equipment should be below () ohms.
A. 50 B, 100 C, 200 D, 1K
28. The data transfer rate of the MIDI system is ( )bit/s, which is asynchronous communication.
A. 31250 B, 15625 C, 7812.5 D.44K
29. The reason why the organ's sense of presence is poor is mainly due to insufficient improvement of the frequency band in the music signal.
A. 1250Hz B, 2500Hz C, 5000Hz D, 12000Hz
30. The squeak suppressor can be used to suppress the vocal sound of the human voice. Usually, the frequency range can be set to be around ( )KHz.
A. 500 B, 6 C, 10 D, 12
31. By highlighting the frequency band above ( )KHz of the signal, you can get a vocal with clear pronunciation and clear sound.
A. 3 B, 5 C, 8 D, 12
32. Estimating the number of decibels in the sound level should be noted that when the loudness of the human ear is increased by a factor of two, the number of decibels in the sound level will increase ( ) decibels.
A. 3 B, 6 C, 9 D, 10
33. Listening to the sound effects of the music and the sound field stimulation effect, the best loudness of the sound should be between ( ).
A. 85dB~90dB B.65dB~70dB C.80dB~85dB D.95dB~110dB
34. The ff in music is equivalent to the loudness of ( ).
A. 70 square B, 80 square C, 90 square D, 100 side
35. The loudness of the 95% loud sound listening time is ( ) hours.
A. 1 B, 2 C, 4 D, 8
36. The fullness of the sound is increased by 100%, and the softness will increase ( )%.
A. 0 B, 5 C, 10 D, 20
37. For halls with large spaces, the absorption of low-frequency sound waves is best handled by ( ).
A. Cavity resonance B, coating sound absorbing material C, tile D, without any treatment
38. The power of the surround channel power amplifier is generally taken as the power of the main channel power amplifier ( ).
A. 1/5 B, 1/3 C, 1/4 D, 1/2
39. The power configuration of the power amplifier system can be estimated according to the volume of the ballroom, and is usually selected at ( ) w / (effective value).
A. 1 B, 2 C, 0.3~0.5 D.0.8~1
40. When the reverberation time of the room is long, the sense of () is increased, the sound is full, but the sound image is not clear.
A. Echo B, direct sound C, reflected sound D, volume
41. The three elements of music are rhythm, melody and ( ).
A. Harmony B, pitch C, level D, beat
42. The speed of sound propagation is ( ) meters per second.
A. 350 B, 344 C, 268 D, 260
43. The generation of standing waves is generally caused by the wall surface of each other ( ).
A. Vertical B, intersecting C, parallel D, arbitrary
44. For the adjustment of the low frequency reverberation time, it is generally used to move ( ).
A. Glass reflector B, polyhedron C, screen D, sound absorber
45. In order to enhance the diffusivity of the reverberation chamber, there is usually no diffuser plate, which is actually a curved plate bent at a central angle of (), which is placed at the angle between the two walls.
A. 90 degrees B, 180 degrees C, 270 degrees D, 360 degrees
46. The relationship between pitch and frequency is that an octave corresponds to ( ) octaves.
A. Five B, one C, four D, two
47. The human ear's judgment on the position of the sound source mainly has two aspects: orientation and ().
A. Three-dimensional feeling B, open feeling C, sense of distance D, warmth
48. Generally, the positioning mode of two-channel stereo is positioned by the left and right speakers ( ).
A. Phase difference B, time difference C, distance difference D, sound level difference
49. The noise gate can be used to cut the undulating head and tail part of the sound source to create a special effect, and the THRESHOLD should be placed at the seat ( ) position.
A. Higher B, lower C, intermediate D, arbitrary
50. Due to the presence of acoustic feedback, the vocalization of the sound reinforcement system generally requires the use of a microphone.
A. PZM B, CTM C, heart-shaped D, omnidirectional
Second, the question and answer questions (20 points)
What are the basic principles of level regulation?
What are the differences between tone and pitch?
What kind of sound effects can be produced by the complementary processing of mixed comb filters?
What are the principles and control techniques of the reverberator?
Dynamic range processor, what features, try a brief description.
How is the sound image position of the music part generally set?
What are the general principles of sound image localization?
What is the reason for the narrow voice, irritability, and poor overall impression? What is the improvement plan?
What is the reason why the sound is dry and "hard"? What is the improvement plan?
What can the auxiliary bus system be used for?
Third, the essay questions (30 points)
Briefly describe the control techniques of auditory actuators.
Briefly describe the role of the room equalizer.
What are the basic requirements that must be considered in studio sound design? Try to give a brief description.
answer
Multiple choice answer:
1, C 2, A 3, B 4, C 5, D
6, A 7, B 8, C 9, D 10, B
11, C 12, C 13, D 14, A 15, C
16, B 17, C 18, A 19, B 20, A
21, A 22, A 23, C 24, B 25, C
26, D 27, A 28, A 29, B 30, B
31, C 32, D 33, A 34, B 35, C
36, D 37, A 38, B 39, C 40, D
41, A 42, B 43, C 44, D 45, A
46, B 47, C 48, D 49, A 50, B
Question answer
1. What are the basic principles of level regulation?
The input level control should be such that when the signal has the maximum peak value, the circuit of this stage operates in a state of no overload, and the output level control should make the output signal in the maximum undistorted state.
2. What are the differences between tone and pitch?
Tone; is a term that describes the quality of the instrument's pronunciation;
Sound sense; a term that describes the subjective auditory effect of a sound field;
The sounds are generally closely related to the instrument. The sounds of the same instrument are in different sound zones. Although the sounds are not necessarily the same, the sounds are generally consistent, and the sound is generally the most relevant to frequency and sound.
3. What kind of sound effects can be produced by the complementary processing of mixed comb filters?
The comb filter complementary processing can obtain a wider sound image augmenting effect; the specific method is: timely processing the sound source signal for 30ms or less (depending on the spectrum of the sound source), and then adding the timely signal and the direct signal to the feed signal. The left channel is subtracted and fed into the right channel, thereby forming a stereo signal with complementary comb filtering effects. The image generated by this signal can fill the sound field between the left and right stereo speakers, and The sound of the sound source is softened.
4. What are the principles and control techniques of the reverberator?
The principles and control techniques of the reverberator refer to the following aspects:
(1) taking a reverberation excitation signal;
(2) equipped with a time machine;
(3) Adjust the sound effect;
(4) adjusting the excitation signal;
(5) Adjust the reverb effect;
(6) Adjust the output gain;
(7) Adjusting the time;
(8) adjusting the diffusion time;
(9) Balanced sound;
(10) Adjust the signal ratio;
(11) Adjust the relationship between reverberation time, reverberation amount and performance speed.
5. Dynamic range processor, what features, try a brief description.
The dynamic range processor has the following features:
(1) Compressor: When the input signal reaches a predetermined threshold, the signal is attenuated;
(2) Limiter: The compression ratio of the compressor is designed to be large enough to become a limiter;
(3) Expander: used to expand the dynamic range of the signal, reduce the gain when the signal level drops, or increase the gain when the level rises;
(4) Noise gate: When the input signal is below the allowable threshold level, the device effectively turns off the signal and the background noise is suppressed.
6. How is the sound image position of the music part generally set?
Mainly the following four ways:
(1) Left and right sound image effects
(2) Deep sound image effect
(3) Sound image broadening effect
(4) Sound image amplification effect
7. What are the general principles of sound image localization?
(1) Low-frequency sound source below 300Hz, because the human ear has a poor sense of orientation, it is generally placed in the center position of the left and right channels;
(2) The sound image of the medium and high frequency sound source can be placed according to the actual position of the instrument during the performance, or the position of the virtual medium can be placed;
(3) The main melody is generally placed in the center position of the left and right channels, and the background sound part is placed on both sides;
(4) harmony and strong and harmonious sources;
(5) Sound image localization can also be used as an artistic expression of music;
(6) If the signal entering the input channel is a stereo program signal, simply place the PAN knobs on the two input channels at the leftmost and rightmost ends.
8. What is the reason for the narrow voice, irritability, and poor overall impression? What is the improvement plan?
(1) 800Hz boost excess, appropriate attenuation;
(2) The attenuation of the frequency band below 300 Hz and above 400 Hz is excessively increased;
(3) The frequency response characteristics of the equipment are extremely poor, and the equipment is replaced with high quality equipment.
9. What is the reason why the sound is dry and "hard"? What is the improvement plan?
(1) 500Hz~5KHz boost excess, appropriate attenuation;
(2) The reverberation is insufficient to increase the reverberation depth;
(3) an acoustic exciter is inserted in the channel to remove the acoustic exciter;
(4) A certain level of overload distortion occurs in a certain level of the system, and the level control button at the distortion is lowered by 5%;
(5) The speaker is overloaded, lower the volume of the amplified sound, or switch to a speaker with a higher power;
(6) The frequency response characteristics of the equipment are poor, and the equipment is replaced by a higher-grade equipment.
10. What can the auxiliary bus system be used for?
(1) The AVX busbar before the PRE EQ unit is suitable for insertion into the frequency equalizer;
(2) The AVX busbar before the orientation PRE is suitable for insertion into a dynamic compressor and a delayer;
(3) The AVX busbar after orientation POST can be plugged into various delays, reverberators or other special effects processors.
On the answer to the narrative:
1. Briefly describe the control techniques of auditory actuators.
(1) Control level adjustment: the input level of the control input to the enhanced line;
(2) Frequency tuning: refers to the second harmonic strobe, and different resonant frequencies should be selected for different program objects;
(3) Mixed volume adjustment: refers to the mixing ratio adjustment of the straight-through main signal and the harmonic signal.
2. Briefly describe the role of the room equalizer.
The room equalizer is used to control the sound field in the room. It belongs to the multi-point frequency control type. Its frequency coverage ranges from 20Hz to 20KHz. It has multiple straight-slip potentiometers placed vertically, which is mainly used to compensate the audio of the listening environment building. The characteristics can be raised or attenuated at different frequency points, and its physical position is like an equilibrium curve. In various applications, it can supplement the frequency components that are lacking in the signal, and at the same time suppress the excessive weight, which compensates for the construction to some extent. The lack of acoustics guarantees the quality of the sound.
3. What are the basic requirements that must be considered in studio sound design? Try to give a brief description.
(1) Sound insulation: Prevent external noise from entering the recording studio, and also prevent a large volume from leaking into the external environment;
(2) Frequency equalization: each frequency component of the recorded sound should maintain its relative intensity;
(3) Audio separation: ensure that the sound from a musical instrument is not picked up by the microphone of an intermediate instrument;
(4) Low cost.
Aluminium wire as a good anticorrosion material,in steel structure surface anti-corrosion(container,dam and sluice gate,Ductile Iron Pipe,bridge etc.)
Aluminum Wire,Zinc Aluminum Wire,High Pure Aluminum Wire,Aluminum Alloy Welding Wire
Shaoxing Tianlong Tin Materials Co.,Ltd. , https://www.tianlongspray.com