Why can CD players play music?

A small dictionary of audio-visual technology

laser record

Sony and Philips jointly developed a digital music CD with two specifications: 12cm diameter and 8cm diameter. The former is the most common and can provide 74 minutes of high-quality music.

CD

A CD-ROM for storing computer data.

Video Compact Disc

Using MPEG- 1 compression coding technology, the image clarity of audio-visual CD is similar to that of VHS video tape.

Supervised cd

The improved product of VCD adopts MPEG-2 coding, and the image definition is improved.

Digital video disc

A new generation of ultra-large capacity optical discs with CD-like appearance will be widely used for recording high-quality audio-visual programs and as a large-capacity storage device for computers.

Doctor of Medicine

The mini recordable CD developed by Sony looks like a 3.5-inch computer floppy disk, but it uses an optical signal pickup system, similar to a CD. MD adopts efficient compression technology to achieve the same recording time as CD, and the sound quality is close to CD.

Digital to analog converter

A device that converts digital audio signals into analog audio signals in digital audio products, such as CDs and DVDs. D/A converter can be made into an independent machine to cooperate with CD turntable, which is often called decoder at this time.

CD turntable

A machine for separating the mechanical transmission part of a CD player.

Oversampling

The sampling frequency is several times the standard sampling frequency of CD system, which is 44. 1kHz. Its purpose is to filter out the digital noise after D/A conversion and improve the high frequency phase distortion of CD player. Early CD players used 2-frequency or 4-frequency sampling, and recent machines have reached 8 times or higher.

HDCD

Short for High Definition Compact Disc, a coding system for improving the sound quality of CD, is compatible with traditional CD, but it needs to be played on a CD player with HDCD decoding, or an external HDCD decoder can be used to obtain the improvement effect.

Bit (bit)

The smallest unit of a binary digital signal, which always takes one of two states: 0 or 1.

bit stream

Philips' technology of converting CD digital signal into analog music signal.

Dolby b, c, s

A series of tape noise reduction systems developed by Dolby Company in the United States are used to reduce the "hiss" produced by tape recording and expand the dynamic range. Type B noise reduction system can reduce noise by 10dB, type C noise reduction system can increase to 20dB, and type S noise reduction system can reach 24dB.

Dolby HX Professional Edition

It is not a noise reduction system, but a technology to improve the distortion of high-frequency recording of magnetic tape, which is often called "upper dynamic margin expansion"

Dolby surround (Dolby)

Encode the post-effect channel into the sound of the stereo channel. During playback, a decoder is needed to separate the surround sound signal from the encoded sound.

Dolby Plachy

(Dolby Pro-Logic)

On the basis of Dolby surround, the front middle channel is added to lock the dialogue in the film on the screen.

Dolby digital (dolby digital)

Also known as AC-3, Dolby Laboratories released a new generation of home theater surround sound system. Its digital audio includes five channels: left front, middle, right front, left surround and right surround, all of which are independent full-band signals. In addition, there is a single subwoofer channel, commonly known as 0. 1 channel. All these channels together are the so-called 5. 1 channel.

AV amplifier

Power amplifiers specially designed for home theaters are generally more than four channels, with surround sound decoding function.

Directional logic surround sound amplifier

AV power amplifier with Dolby directional logic decoding function.

Dolby digital amplifier

Also known as AC-3 amplifier, an AV power amplifier with dolby digital decoding function.

receiving machine

An amplifier with radio function.

THX

The surround sound standard formulated by Lucasfilm Company of the United States has improved Dolby directional logic surround sound system and further enhanced the surround sound effect. THX standard has a set of strict and specific requirements for playback equipment, such as audio and video sources, power amplifiers, speakers and even connecting wires. Only products that meet this standard and have passed Lucas certification can get THX mark.

THX 5. 1

THX based on dolby digital system.

DTS

The discrete channel home theater digital sound system with independent 5. 1 channel is also adopted, reaching or even surpassing the dolby digital surround sound system, and it is a strong competitor of dolby digital surround sound.

Airbag system

A system of SRS company in the United States, which uses two speakers to produce surround sound effect.

Frequency divider

The circuit device in the sound box is used to separate the input music signal into different parts such as treble, alto and bass, and then send them to the corresponding tweeter, alto and bass speaker units for playing.

Double amplifier shunt (double clamp)

A connection mode in which each speaker unit of a sound box is driven by an independent power amplifier channel. A pair of speakers divided into two requires two stereo amplifiers and two pairs of speaker wires. See "Two-line Partitions".

Bidirectional wiring

A connection mode in which two sets of speaker wires are used to transmit the high and low parts of music signals respectively. Two-wire sound separation requires the use of specially designed speakers with two pairs of terminals.

amplifier

Preamplifier and power amplifier are collectively referred to.

power amplifier

The abbreviation of power amplifier is an electronic device used to enhance the signal power to drive the speaker. Power amplifier without auxiliary functions such as signal source selection and volume control is called post-stage.

preamplifier

The pre-amplification and control part before the power amplifier is used to enhance the voltage amplitude of the signal and provide functions such as input signal selection, tone adjustment and volume control. Preamplifier is also called pre-stage.

Late stage

See Power Amplifier.

The previous part of the stage curtain

See Preamplifier.

Combined amplifier

An amplifier that combines preamplifier and power amplifier in one chassis.

Gallbladder machine

Another way of saying electron tube amplifier.

rated power

For power amplifiers, rated power generally refers to the root mean square power that can be continuously output; For the speaker, the rated power generally means that the speaker can withstand this amount of power for a long time without being damaged, which does not mean that it must be pushed by such a high-power amplifier. The difficulty of driving a loudspeaker is mainly determined by its sensitivity and impedance characteristics. Doesn't mean that you can't have a power amplifier with an output power greater than the rated power of the speaker. Just like driving a car, driving a sports car at 300 kilometers per hour does not mean that something will happen. You don't have to drive so fast. Similarly, as long as the volume does not increase blindly, a high-power amplifier can be equipped with a low-power speaker.

Peak music output power (PMPO)

The output power calculated by the instantaneous peak voltage of music signal has more commercial significance than practical function. The power of PMPO can be 3-4 times higher than that of internationally recognized RMS. For example, the root mean square power of early hand-held tape recorders was only 4-5 watts per channel, but this value can be increased to about 20 watts by using PMPO.

Single-ended amplification

The output stage of the power amplifier consists of an amplifying element (or a plurality of parallel elements) for amplifying the signals of plus and minus two and a half periods. Single-ended amplifier can only adopt Class A working state.

Push-pull amplification

The output stage of a power amplifier has two "arms" (two groups of amplifying elements). When the current of one arm increases, the current of the other arm decreases, and the states of the two arms change in turn. For the load, it seems that an "arm" is pushing and an "arm" is pulling, and * * * has completed the current output task. Although Class A amplifiers can use push-pull amplification, it is more common to use push-pull amplification to form Class B or Class B amplifiers.

kind

The conduction mode of power amplifier tube in power amplifier can be divided into Class A, Class B and Class A and B (Class AB).

Level a

Also known as Class A, an amplifier in which any power output element of the amplifier will not be cut off (that is, output will stop) during the whole period of the signal (plus or minus two and a half periods of sine wave). Class A amplifier will generate high heat and low efficiency when working, but its inherent advantage is that there is no cross distortion. Single-ended amplifiers all work in Class A mode, and push-pull amplifiers can be Class A, Class B or Class B. ..

Class b

Also known as Class B, the positive and negative half cycles of a sinusoidal signal are amplified and output by two "arms" of a push-pull output stage in turn, and the on time of each "arm" is half a period of the signal. The advantage of class B amplifier is high efficiency, but the disadvantage is that it will produce crossover distortion.

Class a and class b

Also known as Class AB, it is between Class A and Class B. The on-time of each "arm" of push-pull amplification is longer than half a period of the signal and less than one period. Class A and Class B amplifiers effectively solve the cross-distortion problem of Class B amplifiers, and their efficiency is higher than that of Class A amplifiers, so they are widely used.

deformed

The output of the device cannot completely reproduce its input, resulting in waveform distortion or signal component increase or decrease.

Harmonic distortion

Because the amplifier is not ideal, the output signal not only contains the amplified input component, but also contains some new frequency components (harmonics) which are 2 times, 3 times, 4 times or even higher than the original signal, resulting in output waveform aliasing. This kind of distortion caused by harmonics is called harmonic distortion.

Boundary distortion

Distortion peculiar to class B amplifier. The mechanism of this distortion is that the positive and negative half cycles of the signal are amplified by two different devices, and the waveforms on the positive and negative sides cannot be smoothly connected.

Sound dyeing

Contrary to the natural neutrality of music, that is, the sound is infected with some characteristics that the program itself does not have. For example, the sound you get when you talk to a jar is a typical sound dyeing. Sound coloring shows that there are more (or less) components in the reproduced signal, which is obviously a distortion.

sound pressure

A physical quantity representing sound intensity.

sound pressure level

Sound pressure in decibels.

sensitive

For an amplifier, sensitivity generally refers to the voltage applied to the input terminal when the signal reaches the rated output power or voltage, so it is also called input sensitivity. For a speaker, sensitivity refers to how many decibels of sound pressure can be generated when an input power of 1 w is applied to the speaker at a distance of1m in front of the speaker.

electrical level

The general term for the strength of physical quantities such as voltage, current and power in electronic systems. This level is usually expressed in decibels (d). That is, a voltage or current number is preset as a reference value (0d, the logarithm is taken by the ratio of the quantity to be expressed to the reference value, and then multiplied by 20 as the decibel number of the level (the level value of power is multiplied by 10).

Decibel (d

Units of sound level and sound pressure level.

damping factor

Ratio of load impedance to amplifier output impedance. The output impedance of transistor amplifier with negative feedback is extremely low, only a few tenths of ohms or even less, so the damping coefficient can reach tens to hundreds.

feedback

Also known as feedback, it is a technology that feeds part or all of the output signal back to the input of the amplifier to change the amplification factor of the circuit.

Negative/reverse/reverse feedback

Feedback that leads to a reduction in magnification. Although negative feedback makes the magnification loss, it can effectively broaden the frequency response and reduce the distortion, so it is widely used.

positive feedback

Increase the feedback of magnification. Positive feedback is just the opposite of negative feedback, so be careful.

Dynamic range

The level difference between the strongest part and the weakest part of the signal. For a device, the dynamic range indicates the device's ability to handle strong and weak signals.

Amplitude-frequency response of recording and playback

Referred to as frequency response, it measures the ability of a device to reproduce signals evenly in high, medium and low frequency bands. There are two requirements for the frequency response of equipment. One is that the range is as wide as possible, that is, the lower limit of the frequency that can be replayed is as low as possible and the upper limit is as high as possible; Second, the response of each point in the frequency range should be as flat as possible to avoid excessive fluctuation.

Instantaneous characteristic

The following ability of equipment to sudden signals in music. Equipment with good transient response should respond immediately as soon as the signal comes, and stop immediately as soon as the signal stops, and never drag its feet.

Signal to noise ratio (S/N)

Also known as the signal-to-noise ratio, the contrast between the useful components of the signal and the noise is usually expressed in decibels. The higher the signal-to-noise ratio of equipment, the less noise it produces.

sine wave

A signal with a single frequency component is named because its waveform is sinusoidal mathematically. Any complex signal, such as music signal, can be regarded as a composite of many sine waves with different frequencies and sizes.

wavelength

The propagation of sound waves over a period of time. Wavelength is numerically equal to the speed of sound (344m/s) divided by the frequency.

block

The technology of covering the outside of electronic equipment or wires with materials that are easy to conduct electromagnetic waves to prevent external electromagnetic clutter from interfering with useful signals.

induction quenching

There must be a certain relationship between the output impedance of a device and the connected load impedance, so as to avoid the obvious influence on the working state of the device itself after the load is connected. For the interconnection of electronic equipment, for example, the signal source is connected to the amplifier, and the front stage is connected to the rear stage. As long as the input impedance of the latter stage is more than 5- 10 times of the output impedance of the former stage, it can be considered that the impedance matching is good; When the electronic tube machine is connected to the power amplifier of the sound box, the sound box whose nominal impedance is equal to or close to its output end should be selected, while the transistor power amplifier has no such restriction and can be connected to the sound box with any impedance.

Cooking machine

The power-on preheating process before the new equipment is used makes the sound of the equipment enter a stable state.

Attention Deficit Disorder (ADD)

Refers to recording CD records in analog mode and editing and making master tapes in digital mode.

alternating current

Alternating current refers to the commercial power supply whose current direction will change periodically. Britain and the United States use 60Hz, and China uses 50Hz.

Active crossover (active crossover)

Refers to an active electronic network, which can group the frequency components (bass, midrange and treble) of audio signals before amplification and add them to their respective speaker systems. Although most active frequency division networks are built in speakers such as subwoofers to improve the performance of subwoofers, they can also be used alone in multi-channel systems.

ATRAC

Refers to adaptive transform acoustic coding. It is a low bit rate data compression coding technology adopted by Sony Corporation of Japan in its MD magneto-optical disc recorder.

Audio enthusiast

Refers to people who have a special preference for sound technology.

bandwidth

Refers to the frequency range. For recording, bandwidth refers to the frequency response range of bands or soloists that can be accommodated by the sound system or recording equipment. For home audio playback equipment, bandwidth refers to the frequency range that the system can "hear" during playback, usually in the range of 20Hz or 30Hz to 15kHz or 20kHz.

Bipolar loudspeaker (bipolar loudspeaker)

Refers to the speaker equipment in which the sound generating unit points to the front and back of the speaker respectively and feeds signals in phase. Because the push signals are in phase, there will be no anti-phase cancellation of sound signals and no sharp attenuation of transverse sound radiation. Bipolar speakers usually need to be placed away from the front wall, so that the sound waves pointing to the back can be properly reflected.

cable jumper

Refers to the signal line or horn line. Generally, the purity of copper content in wires is used to indicate the quality of wires. For example, 6N indicates that the copper content of the wire has reached 99.97%. Horn wires with good performance are mostly composed of multi-core wires, and some are composed of single or several thick copper wires. Directional speaker lines are marked with arrows to indicate the connection direction of power amplifier to speaker, and some signal lines are also marked with arrows to indicate the connection direction of signal source to power amplifier.

Digital audio broadcasting

Refers to digital audio broadcasting. Both FM (frequency modulation) and AM (amplitude modulation) broadcasts are digital stereo. British BBC Radio is trying to broadcast in some areas, and in recent years, China has also started to try to broadcast in Guangdong, Beijing and other places. DAB needs a special receiver (radio) to listen.

DAC (digital to analog converter, also known as decoder)

Refers to the digital-to-analog (D/A) converter that converts on/off pulse signals into analog sound signals. DAC has been installed in CD player, but external DAC can improve the sound quality of CD player or other digital players.

Digital audio tape recorder

Short for digital tape. Refers to the digital recording equipment mainly used for professional recording, which uses a rotating head similar to a video recorder (VCR).

Data compression (data simplification)

Refers to a technology that tries to reduce the amount of data needed to store music. Sony Corporation of Japan adopted ATRAC compression coding technology in its MD magneto-optical disc video recorder, while Philips Corporation of the Netherlands adopted similar PASC (Precise Adaptive Subband Coding) technology in its DCC digital video cassette recorder. Both methods use data compression, trying to remove data that people can't hear.

Digital compact cassette tape

The home digital cassette tape recorder developed by Philips in the Netherlands has a sound quality close to that of a CD player, but it is not very convenient to use. Due to the competition with Sony's MD, it ended in failure and has gradually disappeared in the market.

DDD

Refers to the use of digital processing to record, edit and master CD records.

Decibel (decibel)

When measuring the unit of sound pressure change, you can hear the difference when there is a change of 1dB, and when there is an increase of+10dB, the loudness of the sound will double.

Digital output (digital output)

Refers to the digital signal output that can be stored or processed by the attached DAC, which can be electric signal output or optical (optical) output.

Bipolar loudspeaker

It has the same structure as a bipolar speaker, but the signal feeding directions of the front and rear speakers are opposite, so its acoustic radiation mode is inverted "8". Mainly used as surround speakers. THX recommends dipole type surround speakers.

Distortion (deformation)

Refers to unwanted signal or signal change increased by equipment.

Digital video disc

Refers to the video disc used for home entertainment. DVD discs need to be played with a DVD player. Audio and video will be displayed on the screen of a large color TV set equipped with corresponding hardware, or on the monitor of a desktop computer equipped with DVD-ROM.

DVD-ROM

Refers to a read-only CD-ROM similar to CD-ROM, but better than CD-ROM, specifically for computer use. DVD-ROM can have different storage capacities, such as single-sided 4.7GB and double-sided 17GB.

DVD- audio

DVD audio recording, the current version is 1.0, and the standard is 24bit/ 192kHz. At present, there are other music DVDs produced by DVD-video, but they are not the same as DVD-Audio.

DVD-R

As a member of DVD family, DVD-R can be written once and read many times. DVD-R can be single-layer (3.95GB) or double-layer (7.9GB).

DVD-RW

Sony Corporation of Japan, Philips Corporation of the Netherlands and Hewlett-Packard Corporation of the United States jointly launched an erasable DVD disc with a storage capacity of 3GB, which is similar to DVD-RAM. At present, a DVD-RW with a capacity of 12GB is being developed, which can record TV programs for 5 hours.

DVD-RAM

Erasable DVD discs for computers, with designated storage capacities of 2.6GB (single layer) and 5.2GB (double layer).

Divx

A special DVD rental method introduced by American Circuit City Company, after one-time payment, you can watch it for 48 hours, but you have to pay extra for watching it again.

Electrostatic loudspeaker (electrostatic loudspeaker)

Refers to the kind of speaker that uses the electric field force generated by high voltage to push the thin diaphragm to make sound.

raising machine

Refers to the phenomenon that the tone of a recording tape or record fluctuates due to the rapid change of its rotating speed, which is mostly caused by poor operation.

Frequency (frequency)

Usually, the sound with high frequency is called treble and the sound with low frequency is called bass. The audible audio frequency range is between 16Hz and 20kHz.

Front end (front end)

Refers to the signal source in audio system, such as LP disc player or CD player, and sometimes refers to the front stage of tuner (radio head) that processes the signal received from wireless.

hertz

The unit of frequency, 1 Hz, means that the signal changes periodically every second.

Home theater system

Home theater equipment is a combination of audio-visual equipment with excellent performance, which is used to create a sound and picture feeling similar to that when watching a performance in a theater at home. Although the picture quality of most film and television equipment, especially TV sets, is not completely ideal at present, after a certain amount of financial resources are invested, very good audio effects can be obtained.

MD machine (mini CD)

The magneto-optical disc player introduced by Sony Corporation of Japan can record 74 minutes. It looks like a computer floppy disk with a size of 64 mm The MD magneto-optical disc can be pre-recorded or recorded.

Independent mono power amplifier (monobloc)

Refers to a completely independent mono power amplifier, so a two-channel stereo system must use two such independent power amplifiers. Its advantage is that there is no interference between channels.

Moving circle (MC) singing head

This pickup will move relative to the fixed magnet to generate a signal, but the output is lower than that of the moving magnet (MM) pickup.

Moving magnetic pickup

Refers to a small magnetic pickup that moves relative to a fixed coil to generate a signal.

Neckam (Neckam)

Refers to TV sound broadcasting programs with sound quality equivalent to CD.

Ohm (ohm)

The unit of measurement of resistance caused by current, and the impedance value of loudspeaker is measured in ohms. Generally speaking, the lower the impedance of the speaker, the more difficult it is to push.

Oversampling

For DAC system, when the sampling frequency increases, the conversion circuit works easier, and the auxiliary circuit filters out those unnecessary signals more easily.

Passive (passive)

Refers to a circuit or device that does not amplify signals and introduces minimal distortion.

phonograph amplifier

Because the signal level output by the head of LP record player is lower than that of CD record player and tape recorder, it is necessary to add a special preamplifier with frequency equalization, that is, head amplifier. In the past, many preamplifiers or combined power amplifiers were specially equipped with such amplifiers. However, due to the gradual withdrawal of LP from the market, there are few such input stages in current amplifiers.

Quantization (quantization)

Refers to digital audio signals, which are used to represent possible values of various amplitude levels.

Sampling rate (sampling rate)

Refers to the speed at which a digital recorder or player samples signals. For example, the sampling rate of CD player, DCC digital recorder and MD magneto-optical disc player is 44. 1kHz, that is, 44 100 samples per second, while the sampling rate of DAT digital recorder is 48kHz or 44. 1kHz, and the sampling rate of DAB digital audio broadcasting is 32kHz. The sampling rate determines the highest frequency that a digital system can record, so the method of high sampling rate is being studied. For example, Pioneer Japan is developing a system to increase the sampling rate to 96kHz. In addition, DVD-Audio also uses a high sampling rate of 96kHz.

shielded

Refers to some measures taken to isolate wires or equipment from interference.

Subwoofer

Refers to a special speaker, which is used to reproduce the deep low-frequency band that ordinary small speakers can't reproduce.

Audio alarm

It is a part of a record player with a singing head on it.

Transient (transient)

Refers to those short and explosive sounds in music (especially percussion), which are usually difficult to reproduce accurately.

Triamping/Triwiring (pushing)

Refers to a connection mode between the power amplifier and the loudspeaker, which is similar to biwiring and biamp, but it requires three pairs of speaker wires and/or three power amplifiers at this time, which is only applicable to the speakers with three-frequency division and the corresponding input terminals.

Shake it (wow)

Refers to the unstable abnormal sound caused by the slow change of the speed of a tape recorder or recording stand.

Analog music master

It means that both recording and post-production are analog (A) mode, and only the producer uses digital (D) mode to make CD records.

A/B audition comparison (A/B comparison)

Refers to the repeated audition comparison of two different music playing methods.

Absolute polarity (absolute polarity)

When a sound system with correct absolute polarity is used to play a recording product with correct absolute polarity, the forward sound pressure generated by the sound box will be consistent with that of the original sound. When the absolute polarity is wrong, there will be a phase difference of180. For some musical instruments, some people can hear the correctness of absolute polarity.

Ac line regulator

Refers to an audio auxiliary equipment, which is specially used to filter the noise in AC power supply and prevent the audio equipment from being damaged by voltage spikes and surges. Some power purifiers can even be used to prevent lightning damage. In fact, the power purifier is a specially designed and manufactured filter.

sound absorbing material

Refers to any material that can absorb sound waves, such as carpets, curtains, furniture covered with thick cloth, etc.

Acoustic diffuser

Refers to any material or device that can transmit sound waves.

Acoustic feedback (acoustic feedback)

The sound emitted by the speaker will cause the vibration of pickup equipment such as LP turntable and microphone, which will be converted into electrical signals and played back by the speaker again. In this feedback process, the vibration will be strengthened more and more because of its own feedback. This kind of acoustic feedback is the howling of the public address equipment in the venue due to excessive volume.

Acoustic plate absorber

Refers to a sound absorption device that absorbs from low frequency to intermediate frequency through the action of partition. When sound waves hit the sound-absorbing board, the sound-absorbing board will vibrate, thus converting sound energy into a small part of heat energy in the board.

acoustics

Refers to the science that specializes in sound. It also refers to the absorption and reflection characteristics of sound in the listening place, such as "the acoustic characteristics of this listening room are good"

AC synchronous motor (AC synchronous motor)

Refers to the type of motor whose speed is determined by the frequency of applied alternating current. Most of them are used for electric turntable with belt drive.

AC-3

Dolby digital (DD)5. 1 original name of digital surround sound format.

Active crossover (active crossover)

Refers to an active electronic circuit, which can divide the low frequency, intermediate frequency and high frequency of audio signals before amplification and add them to their respective pronunciation units. Although active frequency division network is mostly used in subwoofer, it can also be used in multi-channel system alone.

Active subwoofer (active subwoofer)

Refers to the kind of speaker that is specially used to reproduce low frequencies and is driven by a built-in power amplifier.

Attention Deficit Disorder (ADD)

Refers to analog recording (A) of CD records, while digital recording (D) is used for editing and production.

Analog/digital converter

A circuit that converts analog signals into digital signals.

Adjacent channel selectivity

Refers to the receiving tuner's ability to select the required station and suppress the interference of neighboring stations.

Alternating channel selectivity

Refers to the receiving tuner's ability to suppress the interference of other stations that are two stations away from the station to be received.

AES/EBU digital interface (AES/EBU interface)

Professional interface for transmitting digital audio signals. AES/EBU signal line is a balanced transmission line with XLR plug. In addition, it is also used in some consumer electronic products. It is named after American AES (Audio Engineering Association) and EBU (European Broadcasting Union).

Sense of aggression

Acoustical term used to refer to a performance that moves forward, such as throwing music in front of an audience.

Air induction (air)

Acoustical term used to indicate the openness of high notes or the spatial separation between instruments in a sound field. At this time, the high frequency response can be extended to 15kHz-20kHz. The antonym is plain and heavy.

Air bearing pickup

Refers to the singing arm of LP electric turntable supported by air cushion.

Air bearing turntable

Refers to the kind of turntable supported by an air cushion.

Atmosphere (atmosphere)

Also known as the sense of encirclement. Refers to the sense of encirclement with a certain scale and space generated by movie sound. Usually built by surround speakers.

Ampere (ampere)

The unit of measurement of current, expressed as a.

Analysis (analysis)

It means that the audio equipment can reproduce every detail in the recording in great detail, but it is used in the wrong way, which is extremely lacking in musical atmosphere.

Simulation (simulation)

The voltage change of analog signal is the simulation of sound wave, that is, the voltage will change continuously with the original sound wave waveform. Contrary to digital signals of audio or video signals represented by binary zeros and 1

Image distortion

A widescreen image of a movie or video is horizontally "reduced" by means of lens or digital processing to adapt to the standard aspect ratio of 4: 3. During playback, the original aspect ratio of the image is restored by "back pressure narrowing". The distorted image format can provide the correct aspect ratio without sacrificing resolution.

Anechoic

Literally means "no response"

anechoic room

Refers to a room without reflection. The wall of the anechoic chamber is paved with sound-absorbing materials with good sound-absorbing performance. So there will be no reflection of sound waves indoors. Anechoic room is specially used to test speakers, speaker units, etc.

Clear pronunciation (clear pronunciation)

Acoustical term that an audio device can clearly distinguish tones.

Anti-state adjustment

It is attached to the singing arm to adjust the force exerted on the singing arm, so as to counteract the natural sliding tendency of the singing arm inside.

aspect ratio

Also known as the aspect ratio, that is, the ratio of the width and height of the picture on the display screen. The aspect ratio of standard TV is 4∶3( 1.33∶ 1), and that of widescreen TV and HDTV is16 ∶ 9 (1.78 ∶1).

ATRAC

Adaptive transform acoustic coding is a low bit rate data compression coding technology adopted by Sony Corporation of Japan in its MD magneto-optical disc player.

Audio lovers (audiophiles)

Commonly known as "enthusiasts" or "enthusiasts", it refers to some people who attach great importance to reproducing the sound quality of music. .

Neuroaudio enthusiast

Refers to those who are always fiddling with audio equipment, can't enjoy music to the fullest, but are obsessed with audio.

seeing and hearing

It is the abbreviation of audio-visual products, which refers to those audio-visual products with audio-visual characteristics.