The history of the development of audio

The main features of digital audio

1, high signal-to-noise ratio

Digital audio recording form is a binary code, playback only need to determine the "0" or "1".

Therefore, the noise of the recording medium has almost no effect on the signal-to-noise ratio of the playback signal.

And the analog audio recording form is a continuous sound signal, in the process of recording and playback will be affected by such as tape noise, to be superimposed on the sound signal and make the sound quality deterioration, despite the analog audio in the noise reduction measures, but can not be eliminated fundamentally.

2, low distortion

In the analog audio recording and playback process, the nonlinearity of the magnetic head will introduce distortion, which must be taken to take measures such as AC bias recording, but the distortion still exists.

In digital audio, the magnetic head only works in two states of magnetic saturation or non-magnetic, indicating 1 or 0, there is no linear requirement for the magnetic head.

3, good repeatability

Digital audio equipment after many copies and playback, the sound quality will not deteriorate.

Traditional analog cassette tape recording, each re-recorded once, the noise recorded on the tape have to increase, resulting in each re-recorded to reduce the signal-to-noise ratio of about 3 dB, the sub-tape is not as good as the master tape, the Sun tape is not as good as the sub-tape, the quality of the sound degradation by turn.

4, shake rate is small

Digital audio playback system due to the role of time-based correction circuit, rotating system, drive system instability does not cause shaking, and therefore do not have to ask for as analog recordings of the precision mechanical system.

5, adaptable

Digital audio is recorded in binary code, a variety of processing can be carried out as a numerical operation, and may not change the hardware, only software operation, easy to control the microcomputer, so adaptable.

6, easy to integrate

As a result of digital, thus facilitating the use of ultra-large-scale integrated circuits, and make the whole machine debugging is convenient, stable performance, high reliability, and convenient for mass production, can reduce costs.

Flat-panel audio is composed of audio input devices, signal amplifiers (amplifiers) and speakers, is a complete set of systems, through the exciter (driver) to stimulate the sound board in the bending wave and sound.

After several years of market expansion in the industry, it has been widely used in: home theater systems, background music systems, multimedia sound systems, public **** broadcasting systems, etc..

Advantages

1. Very good directivity.

Generally with traditional speakers composed of speakers, the directivity is very poor, you must stand in front of the speaker, in order to hear a more perfect sound, especially the treble part; and if you stand in the side of the speaker, may be some background or accompaniment sound can not be heard; if you stand in the back of the speaker, may be that sweet song, has become unwilling to appreciate the sound.

The flat panel speakers do not have the above problems, no matter where you stand, you can appreciate the complete, real sound;

2. less sound attenuation.

Traditional speakers, when you lean too close to find the sound is very large, and a little farther away, you feel the sound is much smaller.

The flat panel speakers do not have the above problem, whether you are in close proximity or a little farther away, the size of the sound heard does not have a big difference;

3. The sound of the higher fidelity.

The general traditional horn, which is shaped as a sound cone, when it vibrates to send out the sound, often the sound is concentrated in the throat, after compression, and then spread out, and the sound that people hear, is compressed and deformed sound.

Flat speakers will not have the above problems, only because people used to listen to too much distortion, so once exposed to the flat sound, when you start to listen to it will feel it is very ordinary, and then tend to be attracted by its natural performance;

4. Ultra-thin profile, does not take up space.

Because of the special structure of the flat speaker, the composition of the speaker can be placed in any position, unlike traditional speakers, due to the placement of different positions, heard the effect is very different; Classification

Combination of audio can generally be divided into a mini combination of audio and home theater sets.

The combination of audio is usually referred to as desktop combination audio and floor standing combination audio two categories.

Because of the requirement for a combination of audio to have a relatively high quality of sound, so its two speakers are generally larger.

According to the structure of the host (layers), the audio has a one-piece and layered two categories.

In a one-piece combo stereo, its various parts of the circuit (including the jukebox) are in a shell, this structure is generally used in low-grade combo stereo.

In the layered combination of audio, according to the different grades of the machine is divided into different layers.

The combination of more layers of audio: a layer of record player, a layer of CD player, a layer of tuner, a layer of dual-card recording and playback seat, a layer of tone control, a layer of the main power amplifier.

In the less layered combination of audio, the jukebox, CD player is divided into a layer, and the other is a layer.

Trends

Miniaturization, digitalization, specialization, film and television is the inevitable development trend of home audio.

Miniaturized audio.

Miniature desktop combo stereo has a long history of development, in more than 10 years ago there have been advanced ultra-small combo stereo.

But because the listening speakers, stereo recorders, and recording decks have not been well resolved, they have remained in a lower class.

In order to create a compact audio world, it is necessary to work not only from the amplifier, control components, left and right speakers, but also from the tuner, CD phono and recording deck together.

Digital audio.

Digital technology is a new technology, so digital audio was developed in solving the distortion problem of analog audio noise.

After the audio used digital technology, the digital signal recorded from the sampling frequency to the quantization characteristics, there is a clear resolution, there is no color jitter, get is a very clear image.

And can be interchanged with the host computer, which is incomparable with analog video recording and playback equipment.

Digital recording can be time, name, address together into the tape, using a miniature keyboard to complete the cataloging work, replace the track number, coupled with the remote control function, so that you can automatically search for the desired track, easy to use.

Integration of video and audio equipment.

Digital audio with the development of electro-acoustic technology, film and television technology, computer technology, they can constitute a multimedia film and audio system in the family.

Such a system, you can hear a variety of inputs to add a variety of needs for signal input and function conversion, through computer processing can make the audience see a variety of images and hear a variety of sounds.

Ultra-thin flat panel speakers, the emergence of flat panel audio so that the family combination (home theater, background music) to the ultra-thin direction of development has become possible since 1998 to 2012 flat panel audio has gone through several stages of development, the introduction of the flat panel audio in 1998 Sanno company to the Hualong Dixing (DS), Towieke (TVC) inheritance and development, to the 2008 Chengdu Tianxiang (HVS) developed China's own flat panel articulation technology. ) developed China's own flat-panel sound technology VT called "the fifth generation of flat-panel sound technology", the development of flat-panel audio technology in China is becoming more and more mature, the use of thin mural ultra-thin audio in the family tends to mature!

Embedded audio, embedded audio appeared in 1998 in Chengdu Fuyun (FREENOTE), after more than a decade of development, embedded audio in the "family central network sound system", "embedded home theater" Chengdu Tianxiang (HVS) combined with flat-panel speakers and embedded audio strengths, developed a new generation of home audio system "home health audio system", for the development of home audio to make a tentative step! Loudness

The acoustic characteristics of professional audio should not only meet the requirements of the national standards for acoustic characteristics indicators, but also to meet the subjective listening requirements, because the acoustic characteristics indicators can not fully reflect the actual sound effect, the sound is ultimately good or bad by the subjective listening to the human audio feeling to decide, in the acoustic design, electro-acoustic and acoustic design should be a good match to meet the following subjective listening requirements: the appropriate loudness.

Loudness is the actual listening to the intensity of the feeling, it is directly related to the maximum sound pressure level of the sound reinforcement system indicators, for the performance, only to achieve sufficient loudness, in order to make the sound effects can be fully expressed.

The output power of the system, the placement of speakers will directly determine the loudness of the listening area state: high definition.

Abundance

When used as a speech, must ensure the clarity of the language, if people can not hear the speaker's language, it will affect the effect of the speech.

Therefore, in the design of the electroacoustic system should be fully considered to improve the clarity of speech: enough fullness.

Performance with good fullness can make the human voice full, thick, lively music sound.

In the electro-acoustic system, only through the use of audio peripheral equipment for effective processing of sound signals and reasonable selection of speakers these measures, the fullness of the sound can meet the requirements.

Application

Sound reinforcement system acoustic characteristics of computer-aided design is the use of modern technology to engage in engineering design is an ideal method of high precision, high efficiency, and more importantly, do not have to wait until the end of the installation and commissioning will be able to know the results of the engineering design.

Acoustic characteristics of the computer design system has a very good credibility and accuracy, in the input hall of the building sound data is accurate enough, its calculated data and the final electro-acoustic measurements compared to the results, the error can be controlled within decibels.

For engineering design and installation debugging, this is already enough, and at the same time it also has a very good design and installation debugging guidance, which has been well verified in the previous engineering design.

The use of acoustic CAD computer system to design and calculate the hall, stadium (field), multi-purpose hall, lecture hall sound reinforcement system acoustic characteristics, it means that, without having to wait until the system is installed, commissioned and measured after the completion of the system, you will be able to know the results of its design and installation and commissioning.

In other words, based on the audio system and design calculations given in this design program, has clearly seen the expected acoustic characteristics of the system sound reinforcement system.

Mini-speaker (mini-speaker) is a miniature audio, many friends also called it "USB audio", USB interface to connect to the computer or USB jack, small, portable, novel style.

The mini stereo can be connected to most audio output devices, such as MP3, MP4, MP5, cell phones, computers, etc. (some devices may require an adapter).

The shape design is simple and fashionable, small and exquisite, with many varieties.

The body of the lithium battery power can be carried around.

High power output is also suitable for outdoor use.

Combination of mini stereo is more suitable for placing at home.

Features

1. Compact size, easy to carry, cool appearance, trendy fashion, personalized color matching, fresh and natural.

Size specifications of the largest not more than a soccer ball, the smallest such as the size of an egg;

2, . Set of amplifiers, batteries, dual speakers in one, the first patented technology telescopic expansion *** sound cavity, to solve the mini-speaker *** sound cavity narrow problem, breaking decades of restrictions on the specifications of the speaker's appearance, compressed to the limit;

3. Do not need a long audio line, do not need external power supply, whether it is the mountains and rivers like fresh rhymes, or *** surging DJ dance music, can be shown to the fullest!

4. Simple and clear design, easy to use.

Using the USB standard interface power supply and audio input, driver-free USB interface plug and play, fully compatible with WINDOW 95 98 ME 2000 and XP operating system.

With 3.5mm stereo audio input interface linking laptop, desktop PC, cell phone, PSP, Walkman, MD, Mp3, Pocket PC, PDA, Mp4, repeater, iPod, cell phone and other devices;

5, mini speakers only need to be connected to the laptop, cell phone and other devices, without the need for a power supply to play beautiful music.

Some speakers are equipped with a high-capacity lithium battery inside, the product can play 5-8 hours of music.

Dual power supply mode is more durable.

6, portable performance for outdoor sports explorers, recreation, cycling outdoor sports, but also for computer amplification, as a small computer speakers.

In short, the mini speaker because of the small size of the long playing time, the external speaker sound, unlike the traditional MP3 need to bring earplugs, hurt the eardrums, has been more and more widely loved! Especially sports small speakers, bicycle audio and so on! Selection guidelines

Since the use of desktop stereo clear location and purpose of use, so we can initially judge the desktop stereo most of the cases are played on the radio, pop music and other vocal content, so for the sound of the speaker working band does not have to ask for too low.

Usually the lowest performance frequency of the audio system can be selected at 40Hz or more, of course, this is only one unit for each speaker.

If you can guarantee two units per speaker (there are also coaxial speakers embedded in the bass and treble speakers), then the sound effect will be much better.

It's as if an instrument is never as expressive as an orchestra.

Layout of a desktop stereo

Although it is a desktop stereo, some desktop stereos have speaker sections that can be split.

So how do you lay out the speakers in a split installation?

Perhaps you will say, a **** just two speakers, but also to speak of what layout? Of course, if your speakers are placed in the corner or your speakers are placed in the center of one side of the room, to achieve the sound effect is very different.

Generally speaking, the two speakers of a small desktop stereo are recommended to be placed closest to the listening position, on an axis of symmetry in the room.

The two speakers should not be too far apart, otherwise it would be difficult to generate a balanced soundstage with the power of the two speakers in a desktop stereo.

Because it is not a professional listening room with sound-absorbing structures, it is best to minimize the number of times the sound is reflected back and forth in the room, to prevent the noise from increasing because of the number of reflections, and to avoid the imbalance of the left and right soundstages caused by the different reflection paths of the two channels.

Of course, every separable desktop stereo comes with speaker cables at the beginning of the purchase.

The speaker cables are of equal length, and should not be shortened during installation for fear of inconvenience, or it will make no difference if the two speakers are placed far apart or near each other.

If your speaker cable is not long enough, or for other reasons need to be purchased separately, then it is recommended that you buy a higher quality hi-fi speaker cable, because the resistance loss of such a speaker cable is small sound quality is higher, in addition, some speaker cable also has the ability to anti-interference.

Of course, when you buy them, you also need to equalize the length of the line.