Ⅰ. What are audio products?
Ⅱ. Classification of audio products
Ⅲ. How to choose audio equipment?
Ⅰ. What are audio products?
Audio products are devices that reproduce, record, or process sound. It includes microphones, radio receivers, AV receivers, CD players, tape recorders, amplifiers, mixers, effects units, headphones, and speakers, among others. Audio equipment is widely used in many different scenarios, such as concerts, bars, conference rooms, and homes where reproduction, recording, and volume enhancement are required. Electronic circuits, considered part of audio electronics, can also be designed to perform certain signal processing operations in order to make specific changes to signals while they are in electrical form. Audio signals can be created synthetically by electronic devices generating electrical signals.
Audio products were traditionally designed using analog circuit technology until digital technology advanced. Furthermore, due to their compatible digital nature, digital signals are capable of being processed by computer software in much the same way as audio electronics. Today, both analog and digital design formats are still in use, and the use of one or the other largely depends on the application.
Ⅱ. Classification of audio products
Without a sound source, it is impossible to restore the sound with speakers. The audio information recorded on the audio source carrier must pass through the corresponding equipment to read the information, and then transmit it to other equipment in the audio system in the form of electrical signals. We collectively refer to devices that play audio carriers as audio devices. It includes hard disk player, network player, game console terminal, TV/smart projection, set-top box, KTV karaoke machine, VOD system, VCR-VHS video recorder, CD player, MD recorder, electronic musical instrument, A/V receiver Internet radio, PC/MAC/laptop, tape player, digital audio recording/playback system, CD/DVD/Blu-ray recorder, portable recording device, multi-channel recorder, digital broadcast transmitter, Internet radio, portable music player, and etc..
(1) Vinyl turntables and vinyl turntables
As a carrier of sound and music, vinyl records occupied almost the entire 20th century. However, China entered the CD era in 1992, a large number of vinyl production lines were eliminated, and the price of vinyl records dropped from about 30 yuan to about 15 yuan. However, due to the preference of collectors, the price of vinyl records has gradually risen since 1994, and it has exceeded 100 yuan in 1996. Currently, the value of collector's editions ranges from several thousand to ten thousand yuan. In 1998, the last vinyl production line in China was closed. At present, vinyl records in the domestic market are imported from overseas or second-hand. Vinyl record players generally cost several hundred yuan in the second-hand market, and usually the buyer needs to spend several hundred yuan to replace the needle, and the total cost is thousands of dollars. The first-hand vinyl record players are all imported, and they cost at least two thousand yuan.
Although the vinyl record is a product of modern society, it is still considered the most sound medium until now. There are still a considerable number of friends trying to buy vinyl discs. These discs have undergone rigorous production, and the content is also extremely strict recording, so the cost is high, the number of remaining discs is small and the price is expensive, and a few are even called heaven discs.
(2) Broadcast radio
We all probably had radios in our homes at one time. Radios were commonly called semiconductors in the past, and they were mainly used to listen to radio wave sound signals from radio stations. The signals received in China mainly include AM (frequency modulation) and FM (amplitude modulation). Although the appearance of the radio seems to be relatively simple, its working principle is relatively complicated. The internal structure is also composed of frequency conversion stage, intermediate frequency amplifier, power amplifier circuit, triode tube, receiving antenna and other components. But for ordinary users, all they need to do is to adjust the frequency band and listen to different information or entertainment programs. In the era when television was not yet popular, radio played a relatively important role in people's lives.
Radios include vacuum tube radios, semiconductor radios, and transistor radios. Although radios are not as common today, they still serve many people. Car radios can be seen everywhere in taxis, and some speakers are also designed with radio functions.
(3) VCD player, DVD player and combined audio system
In the past, it was popular to buy a VCD in the family. Watching DVDs or singing karaoke at home, erecting a few large speakers in the house or hanging a few large speakers on the wall became a trend at that time. It seems that since then, karaoke has really entered private homes as a form of entertainment. No matter how you sing, everyone can shout a few voices at home instead of going to the karaoke hall. And the concept of home theater has slowly been deeply rooted in the hearts of the people since then.
The VCD player reads the VCD disk through the optical head set inside. The video that can be played by VCD machine is generally extended as MPG or DAT, and the standard format is 352*288, 25 frames/s, 1394kbps. Through the adapter to play on the TV, we can watch movies, music MV and other recorded programs or sing karaoke. It was all the rage back then because of its rich functions and good usability. The VCD players at the beginning were relatively large in size, and many ultra-thin products appeared later.
Users' desire for high-quality audio-visual enjoyment has led to the emergence of DVD players. DVD players can play DVD discs and high-definition video, and can also play CD discs with recorded songs. It is more powerful than Lian Po's old VCD player in terms of functionality, and it is gradually popularized in every family.
The term home combination audio is actually relatively broad. Generally speaking, it refers to home theater AV audio, which has shocking and powerful effects, excellent sound quality, and relatively expensive prices. It can be used as a theater speaker when enjoying movies at home, or it can be used to listen to songs and perform entertainment activities.
(4) Portable CD player, single player, Mp3
Portable audio playback devices have already penetrated into our lives. Whether it is a portable CD player that is proud of its sound quality, a Walkman with a tape, or a small but large-capacity Mp3, they are all devices that we are all too familiar with.
Portable CD player can play CD discs with you, it is also called Discman. It was first launched by SONY in 1984, and then became popular quickly. It was very expensive at the beginning, and gradually it was accepted by the public. You can use it to listen to your favorite music albums. The CD format has little damage to sound quality, high compression bit rate, high degree of restoration, and excellent sound quality. It is the first choice for those who pursue sound quality. Of course, we'd better buy genuine album discs. CD players have undergone a process of evolution from heavy to thin. Most of the popular portable CD players are very fashionable in appearance, easy to operate, and rich in functions, but there are also some large CD players for desktop use that people like.
The popularity of the player to play tapes to bring us music enjoyment is quite high. And its earliest Chinese name is Walkman. It is evolved from Sony's Walkman series. The world's first Walkman was the Walkman portable tape player developed by Sony in 1979, marking the birth of the concept of portable music. The portable tape player is commonly known as a single player. Whether it is a genuine tape, a pirated tape, or a mouth tape, it can be used, and some of them can also be used for radio and recording. The beautiful appearance and simple operability are very attractive, and the price is not expensive. For example, the cheapest domestically produced single player is only tens of yuan. After dominating the market for many years, it was gradually replaced by Mp3.
Mp3 refers to a portable player that can play many audio formats such as Mp3. MP3 players can also upload and download computer files in other formats, and some can also support video playback. It uses a special data compression algorithm to process the original audio signal, so that the size of the digital audio file is only one tenth of the original, but the quality of the music does not change much, so that it can be recorded in a smaller format. Store a large amount of audio data in the storage space. If we use CDs, there may be only a dozen songs on a disc, and the same is true for tapes. But a larger-capacity Mp3 player can store hundreds or thousands of songs. However, the degree of reproduction of Mp3 recordings with different bit rates is different. Although many brands have their own Mp3 industry, and there are many products with excellent design and good sound quality, Apple's iPod series can be said to be the most representative of Mp3 fashion culture.
2. Audio
Audio is an integral part of electro-acoustic equipment, including speakers, headphones etc. It is used to convert an audio signal into a sound signal.
(1) Loudspeaker box
A loudspeaker box is a transducer that converts electronic signals into sound, and is a device that converts audio signals into sound. Its function is to convert audio electrical energy into corresponding sound energy and radiate it into space. Multiple speakers can form a sound group. The effect of the sound is not as intuitive as the display screen, so the final performance of the sound is determined by the sense of hearing of the human ear. Therefore, this result may vary from person to person. Common loudspeaker boxes include: bookshelf loudspeaker box, floor-standing loudspeaker box, wall-mounted loudspeaker box, embedded loudspeaker box, mobile Bluetooth loudspeaker box, monitor loudspeaker box, array loudspeaker box, theater loudspeaker box, stage loudspeaker box, teaching loudspeaker box, musical instrument loudspeaker box, conference room loudspeaker box, wireless loudspeaker box, multimedia loudspeaker box, Karaoke loudspeaker box, outdoor loudspeaker box, satellite loudspeaker box, center loudspeaker box, etc.
(2) Headphones
Earphones are a pair of conversion units that receive electrical signals from a media player or receiver and convert them into audible sound waves using speakers close to the ears. Headphones are connected to the media player using a plug. The advantage of this is that it can listen to the sound alone without affecting others, and it can also isolate the sound of the surrounding environment.
According to the sound driving method using the transducer, earphones can be divided into electrostatic earphones, moving coil earphones, moving iron earphones, coil iron hybrid earphones, and isomagnetic earphones. According to the shape and function, it can be divided into open earphones, semi-open earphones, closed earphones, headphones, earmuff earphones, on-ear earphones, in-ear earphones, wireless earphones, active noise reduction earphones, recording Studio monitor earphones, stage monitor earphones, sports portable earphones, home entertainment earphones, radio and television production earphones, medical audiometry earphones, air traffic control earphones, hearing aid earphones, DJ earphones.
(3) Speaker
A speaker is a transducer device that converts electrical signals into acoustic signals. The performance of the speaker has a great influence on the sound quality. The loudspeaker is the weakest part in the audio equipment, but it is the most important part for the sound effect. There are many types of speakers, and their prices vary widely. Audio electrical energy, through electromagnetic, piezoelectric or electrostatic effects, causes its cone or diaphragm to vibrate and resonate with the surrounding air to produce sound.
3. Microphone
Microphones are transducers that convert sound into electrical signals. It generates voltage through the action of sound waves on electroacoustic components, and then converts it into electrical energy, which is used in various sound amplification equipment. Common types of microphones include conference microphones, interview microphones, recording studio microphones, singing microphones, musical instrument microphones, karaoke microphones, dynamic microphones, condenser microphones, stereo microphones, directional microphones, 3D sound pickups, omnidirectional pickups,radio microphones and so on.
A power amplifier refers to a device that can use less energy to control greater energy. The function of the power amplifier is mainly to amplify the weaker signal input by the audio source equipment, and generate a large enough current to drive the speaker to reproduce the sound. The types of power amplifiers include pre-stage power amplifier, post-stage power amplifier, integrated power amplifier, mono power amplifier, multi-channel power amplifier, tube power amplifier, transistor power amplifier, integrated circuit power amplifier, digital power amplifier, switching power supply power amplifier, power amplifier with microphone amplifier, headphone power amplifier , Karaoke power amplifier, voice power amplifier, general professional power amplifier, mini power amplifier, car power amplifier, surround sound power amplifier.
5. Mixer
A mixer is an electronic device used in the professional audio field to mix, route, and adjust volume, timbre, and dynamic range of audio signals. Depending on the model, the mixer can be used for analog and digital signals. Finally, the adjusted signals (level or digital sampling) are combined together to become the synthesized output signal. Common mixers include analog mixers, digital mixers, conference mixers, active mixers, DJ mixers, automatic mixers, recording mixers, sound reinforcement mixers, and analog audio synthesis mixers, signal splitter mixers, theater mixers, mini mixers, multi-channel mixers, touch screen mixers, portable mixers, live production mixers, wireless broadcast mixer, cable broadcast mixer, built-in sound card mixer.
There are many types and functions of audio processor devices. Generally speaking, it is a series of audio equipment that corrects, processes audio signals. A digital audio processor is a digital audio signal processing device. It first converts the multi-channel input analog signal into a digital signal, and then performs a series of tunable algorithm processing on the digital signal to meet the application requirements of improving sound quality, matrix mixing, noise cancellation, echo cancellation, and feedback cancellation. Analog conversion outputs multi-channel analog signals. It includes compressor, frequency shifter, noise reducer, exciter, expander, crossover, effect processor, crossover processor, dynamic processor, media matrix processor, digital audio processor, DPS accelerator , format converters, cross-fading converters, AD/DA converters, sample rate converters, keyboard/drum controllers, audio conferencing processors.
Ⅲ. How to choose audio equipment?
With the rapid development of nonlinear technology, there are more and more operating systems and applications for audio and video, and various audio devices abound. Regardless of the price of the device, someone will buy and use it. Expensive equipment is good, but it may not be the most suitable choice. Therefore, we must first understand the characteristics of our own voice, and then choose the corresponding equipment according to the characteristics of the sound.
1. Microphone amplifier
Like microphone amplifiers, there are many brands and types of microphone amplifiers. It is generally used in conjunction with better condenser microphones. Its main function is to supply power to the microphone and act as a pre-amplifier for the microphone. Some of them also have the functions of adjusting the balance, voltage limit, limit, signal-to-noise ratio, input and output current of the microphone, and even increase or decrease the tooth sound and a function that excites for a certain frequency band.
The microphone amplifiers produced by various companies have different emphases and preferences, some are more natural, some are more warm, and some are more individual. Some mic preamps are transistor and some are tube. The microphone amplifier should be selected according to your own conditions and preferences. In addition, we'd better use it under the guidance of professional technicians, otherwise improper debugging will affect the sound effect instead. Especially those mic amplifiers with functions of adjusting equalization, pressure limit, limit, signal-to-noise ratio, input and output current, increasing or decreasing tooth sound and stimulating a certain frequency band, once adjusted improperly, it will affect the fullness of the sound and sound quality. Many sound cards now have built-in microphone amplifiers, and various parameters have been adjusted. The built-in microphone amplifiers on some sound cards work well, and avoid many troubles caused by unprofessional debugging techniques.
2. Monitor and speaker headphones
The meaning of monitoring is to remove the beautifying elements in the sound, so as to restore the real sound, so as to find the problems in the sound and make corresponding adjustments in the production. The standard for identifying sounds is a kind of intuition and habit in one's own hearing. There are many professional sound engineers who are always used to working with their usual monitor speakers and headphones no matter which recording studio they are mixing and synthesizing in. Monitor speakers and headphones are more like auditory reference objects and rulers, allowing us to accurately grasp the indicators of sound. Therefore, the purpose of monitor speakers and earphones is to help us establish a sound judgment standard, tell us what the real sound is, so as to find problems in the sound and improve our own sound.
3. Microphone
Microphones are no strangers to everyone. From headsets for video, to dynamic microphones for karaoke, to world-renowned capacitor transistor or tube microphones, there are many types. It is like the lens of a camera, except that one collects sound and the other collects images. We need to choose a microphone according to our own recording equipment, recording environment and our own sound conditions.
Generally, the DJ or host of the radio station uses a dynamic microphone, because it can make a sound very close to it, and it will not spray the microphone. This saves a lot of effort for someone like them who spends a lot of time talking in front of the microphone. And those hosts who are used to speaking in a low or virtual voice will feel more comfortable with dynamic microphones. Most of the microphones used for dubbing are condenser microphones, especially the vocal microphone with the icon of "heart".
Everyone's sound conditions and language habits are different. If possible, we'd better try all kinds of different microphones before making a choice. Some people have a heavy dental voice, some have a heavy nasal voice, and some have a heavy guttural voice. They will have different performances in front of different microphones. There is no hard and fast standard here, and the choice of microphone is all a matter of personal preference.
4. Sound card
A sound card is an audio device based on a computer platform. It is the key to connecting external audio equipment to the computer. Through the sound card, the sound signal collected by the microphone is sent to the operating system of the computer for editing and processing, and then the processed audio file is sent out.
Sound cards are divided into two categories: motherboard integrated sound cards and external sound cards. The motherboard's integrated sound card is the sound card that comes with the motherboard. It is generally set according to the audio standards in life, and the sound quality cannot reach professional standards. There are various levels of external sound cards, and the sampling frequency ranges from 44.1 to 48, 96, and 192. The pros and cons of AD/DA digital-to-analog converters are the key to classifying external sound cards. A stands for analog signal, D stands for digital signal, and AD conversion is to convert the analog signal A recorded by the microphone into a digital signal D that can be recognized by the computer, and then send it to the operating system for editing. Then it converts the digital signal D in the operating system into an analog signal A that can be heard by the human ear through DA conversion. The conversion quality of the converter determines the level of the external sound card. The better the AD/DA digital-to-analog converter, the higher the level of the sound card. However, the digital-to-analog conversion can only enhance the restoration of the sound, and cannot change the essence of the sound. In other words, it is not that the more advanced the sound card, the more beautiful the sound recorded. It is based on the restoration of reality as the standard, and can only restore the sound to the original sound.
5. Audio cable
Audio cable is a professional audio cable that connects audio equipment such as microphones and microphone amplifiers, sound cards and monitor speakers. Unlike ordinary wires, a good audio cable can carry the audio signal intact without loss.
