Viewing the development of AV technology from the change of audio-visual entertainment

We are in an era full of change and rapid development. There are too many things to accept and master, and we have no time to think about it: What will happen tomorrow?

Acousto-optic technology of modern science and technology has "reproduced" the world visually and aurally. More and more realistic images and sounds have greatly enriched our senses. Facing the enjoyment brought about by the constantly updated high-tech, under the impact of a large amount of information, people who are already in danger of "aesthetic fatigue", look back and look at the "sensory hunger" only a few decades ago "Thirst" may be intriguing.

Pioneer of audiovisual entertainment

In the history of art development, to say that there is a "video entertainment" art form that has a greater impact on people's lives, it must be a shadow play. As the name implies, shadow puppets are made of leather. For the sake of firmness and transparency, cowhide and donkey skin are better. When coloring, five pure colors of transparent pigments such as red, yellow, green, green and black are mainly used. Because of these special materials, shadow figures and props are illuminated by the back light, and the shadow projected on the screen is magnificent and crystal clear, with a unique beauty. This is a "shadow"; its "tone" is a "civil and martial arts group" with several functions. The gongs and drums sounded, and they sang and sang. Of course, the sound is very "fidelity", because it is a real person who really sings, and does not pass any electro-acoustic amplification equipment.

For the audience, what they see is just a screen that changes with the plot. What they hear is the sound effect that is synchronized with the picture, which can fully exert the effects of various special effects and can also fully arouse the imagination of the audience. This is the charm of shadow puppetry, which is quite like our projection TV today!

Shadow art is a wonderful flower in Chinese folk culture. As the earliest form of curtain culture and entertainment in the world, it skillfully combines folk carving and painting skills, while also absorbing the essence of traditional opera, performance and literature and art.

Our hardworking and wise ancestors were really blessed. As early as the Western Han Dynasty, they had begun to enjoy such a high level of audio-visual entertainment. By the Song Dynasty, the development of shadow play was already very prosperous. According to relevant records: In the capital city of the Northern Song Dynasty at that time, that is, Kaifeng, Henan, there were performances of small shadow opera groups in many streets.

The reason for the shadow play used in shadow play, and the performing arts methods, also played an important leading role in the invention of modern movies and the development of modern movie art.

(The movie "Alive" stills)

Another form of audio-visual entertainment that is still in use today is the slide projector.

In 1654, German Jewish Kirchner first described the invention of the slide projector. The shell of the original slide projector was knocked into a square box with iron skin, and there was an exhaust tube similar to a chimney on the top, which was used to discharge the heat and black smoke generated by the burning of the candle; there was a cylinder directly in front of it. The convex lens forms a simple lens, and the focal length can be adjusted; the light source is installed in the box, and the original light source is candlelight. When in use, put the slide projector in a black room, insert the slide into the groove behind the convex lens, light the candle, the candle light is condensed through the mirror to illuminate the transparent picture, and then through the lens, the real image is formed on the wall curtain.

The earliest slides were made of glass and painted by hand. In the middle of the 19th century, after the celluloid film was invented, slides began to be produced using photographic transfer.

The industrial production of the slide projector began in 1845, and the light source was changed from the original candle to the oil lamp and the steam lamp, and finally the electric light source was used. In order to improve the quality and brightness of the picture, a concave reflector is also installed behind the light source, and a plano-convex lens for light collection is installed between the light source and the picture. The high-power light source causes the temperature of the chassis to rise. For heat dissipation, an exhaust heat dissipation structure is added to the slide projector. In order to facilitate and standardize the operation, the film transfer is also changed to automatic.

The slide projector that we use widely today is based on the development and improvement of the slide projector in the 19th century.

The slide projector can also auto focus and can be remotely controlled. When you travel, you take a lot of film, which can be developed into a slide. There is a film called "reversal film" that is specially used for slide show purposes.

The slide projector is not only an entertainment method, but also widely used in teaching, scientific research, conferences and stage performances.

Compared with the shadow play, the slide projector seems to be "silent", but usually the voiceover of "narration" is still indispensable, and even later developed a model that uses recording technology to synchronize the picture with the sound.

The performance of the shadow play depends on the level of the artist, so the slide projector, although it is a machine, is still not good for "serving". Sometimes it is a very important report meeting, but there are often problems with automatic film production. Or back and forth, the screen should appear, the operator sweats and the audience suffocates. And from time to time, there are one or two pictures of heads down "take the big top", which has an unexpected effect on the active atmosphere of the venue.

In the famous large-scale opera and dance epic "Dongfanghong", the Great Wall, the Yangtze River, the Yellow River and other grand backgrounds are all played by slides. These effects are not rare at the moment. Forty years ago, they let the staff exhaust. thought. Because the stage in the Great Hall of the People is high and wide, and the background curtain is particularly large, a slide projector is so weak that it can't even see the shadow. The staff put a dozen slide projectors in front of the stage, and then divided the area on the curtain. Each slide projector took an area and spliced ​​it into a whole background.

What's more creative is that the background of the stage has red flags fluttering and the yellow river sparkling from the sky! Can the slide show a moving image like a movie? It turns out that a similar bamboo is placed in front of the lights The curtains are constantly moving, and the light is transmitted through the gaps of the bamboo curtains, forming the effect of the red flag waving and the waves rippling. The clever crew members put the application of the slide projector to the extreme.

A, V and home theater

When it comes to home theater, people often know that it has two meanings, namely "view" and "listen", the English abbreviation is AV, this "A" is "Audio", audio means, "V" is "Video", The meaning of the video.

Speaking of this, in the history of modern civilization, these two things were originally separate, but they were all related to a great inventor, Edison, who had more than a thousand invention patents in his glorious life, of which the greatest impact on human life In addition to electric lights, there are also gramophones (1888) and movie machines (Edison ’s 1895 "movie movie projector" patent, at the same time as the recognized inventor of the movie machine in the history of cinema, the French Lumiere brothers).

Movie machines can be considered as a continuation of the slide projector, because their basic structure is the same, with the same optical path. The difference is that the picture is constantly changing, in order to use the "visual persistence" principle to form a moving image in the viewer's brain.

The earliest movie was a silent movie. Later, with the narration of the projectionist, even if there was a voice. Later, he invented the method of synchronizing the recording of sound information on the film, and the sound was really integrated into the movie.

From the perspective of audio technology, since the birth of the drum phonograph, people have heard the sound recorded on the media for the first time. They are very shocked and have aroused great interest. Sound recording and playback technology and the subsequent radio broadcasting technology have produced countless audio enthusiasts in the past hundred years. They have made radios, amplifiers, various speakers and various interesting circuits by themselves. They have played a great role in the progress of audio technology. Promote the role.

The invention of the TV set enabled radio broadcasts to simply play sound signals, add images, and transmit live reports of news reports and sports games from far away. Video incorporates Audio, making broadcast media even more powerful and attractive.

Some audio enthusiasts were later dissatisfied with having only "Audio" and wanted to attack "Video", trying to assemble TVs with oscilloscopes, but not many succeeded. I still remember that in the early 1970s, a worker in my father ’s unit, who was particularly capable, installed a “TV” like this. When I heard the news and visited, I saw that after a long day of sweating, he was the only one left. Mumbled to himself: There was a shadow last night .... However, his machine still made great achievements. It is said that once a TV station broadcasts "Girls Selling Flowers", dozens of people, men, women and children crowded the door of his dormitory and was moved by the artistic effect of TV soundtracks. .

At that time, if you heard who was showing the film in your own home, no need to ask, it was definitely not a capitalist, let alone a "leading cadre", he must be a master of the projection team, and the moon near the water tower first. Such good things can only be dreams for others. It's very comfortable to be able to move a small bench to watch open-air movies on the weekend evening, and no one in front is seriously covered.

Most enthusiasts continue to travel in the audio field, from 3DDXX to 2SKXX to assemble the amplifier themselves, from "Fei Le" and "Taixing" to "Xiyashi" and "Odyssey" designed speakers, with the audio "fever" The boom surged into the mainland from the southeast coast and heated up dramatically. "Welder Schools" are getting harder and harder, because the appearance of high-quality sound sources such as FM, LP and CD provides a huge space for sound upgrades. The "purchasing school" silver among enthusiasts has also thrown objects. This is the Hong Kong businessmen who have attacked the market in a big way. Their promotional advertisements are as beautiful as the foreign brands they have come to. In any case, the audio boom has caused people to hear sounds that have never been heard before from tube radios or small "semiconductors", and enjoy unprecedented enjoyment. Once upon a time, audio enthusiasts were called the "fans".

The development of "Video" takes another road, a road of professional production. Due to the focus of national investment, the production and import of TV sets began to heat up rapidly in the late 1970s. “DIY” TV sets are not as cost-effective to buy in all aspects, and they require a lot of equipment for debugging, so they will be available in a very short time. Completely dispelled the idea of ​​the "welder school" homemade TV.

Because the TV sound adopts the FM system, the transmission quality is guaranteed. Early televisions also paid more attention to the playback effect of the TV sound, and even brought a small two-way built-in speaker. It is puzzling that as the screen of the TV is getting bigger and bigger, the sound quality is getting worse. Some people even suggest that the TV does not have a "chicken rib" of speakers; others say that this is a "congenital deficiency" of the TV. If you do n’t believe me, look at the English word of television—television, where vision means “visual” and “scene”, and its Chinese name is the same, not related to sound.

Therefore, the "A" and "V" that had been close to each other became alienated again.

What really reunites "Audio" and "Video" is the "Home Theater".

The concept of home theater began in the United States in the mid-to-late 80s. The reason is that the LD player was launched, providing high-quality Audio and Video signal sources. The LD system was quickly supported by major film companies in the United States, and was suppressed by the conversion of movie films. A large number of LD program CDs are listed. At the end of 1987, Dolby Laboratories in the United States launched a home-use Dolby directional logic surround system, in which the separation effect of each channel is close to that of a professional movie theater, which caused a lot of sensation in the industry for a while.

When the Lucas Film Production Company of the United States extended its famous THX film surround sound system to home theaters, it made strict and detailed regulations on audio equipment and technical requirements, and even had "harsh" on the acoustic environment of the audiovisual room. "Regulation. In this way, the audio indicators of home theaters have reached a very high level, which is beyond the reach of ordinary Hi-Fi products, and includes an important factor that is easily overlooked, such as the listening environment. Therefore, in the eyes of Americans, home theater belongs to the same level of luxury as yachts or villas.

VCD is a simplified version of LD that was later produced in China. VCD is directly connected to the TV through the AV terminal or RF (radio frequency signal) cable. In many cases, even only mono signals can be played back. At this time, they cannot be called "home theaters" because of that. It's not even as good as the combination of a video tape recorder (CTR) and a TV. But together with higher-level power amplifiers, speakers, and TVs, they form the prototype of a "home theater"-although they have not passed (and certainly cannot be passed) THX "certification", but in any case, they can be in their own home I watched a movie vividly and vividly. Although the image was not clear enough, the sound was still passable. When watching "big movies", the sound of guns inside was not the same bang?

And until now, when it comes to home theater, people usually immediately think of multi-channel amplifiers and several speakers including subwoofers, plus a DVD. Audio once became very beautiful. As for the "Video" TV set, it looked a little "gray", because it is very readily available, almost every family has it, even if it is an old TV with a spherical screen, just connect the video cable. Can be used, not worth mentioning. As for the environment, few people talk about it. In many cases, after a lot of problems, I turned back and thought: When the decoration was originally carried out, how did it not consider some of the most basic problems such as sound absorption and embedded wires What?

It is worth mentioning that when the slide projector came to this day, the real "terminator" has appeared, that is, the projector + computer. The emergence and rapid popularity of notebook computers, coupled with strong Internet support, have made people give up the traditional slide projector without hesitation.

Also because of the popularity of computer technology, new content has been added to the audio-visual entertainment method. If computer multimedia is popular with young people and meets the general audio-visual requirements, the Home Theater Computer (HTPC), which has appeared in the past two years, provides A more high-end option, its vitality and "threat" to existing AV signal source equipment may appear in the next few years.

This is an important example of the technological revolution changing people's lifestyles.

Video explosion

In the home theater equipment, the role of the TV is very simple and clear, it is a "display".

The cathode ray tube (CRT) has a long history. It has been used as a color display on televisions for more than 50 years. Until the 1990s, it has always dominated the world.

In today's home theaters, its video equipment is no longer limited to "right-angle screens" and "flat screens" that use CRTs. The flat panel display device (FPD) has been conceived for a long period of 40 to 50 years. In recent years, there have been major technological breakthroughs. This breakthrough has been quickly applied to products. The rapid replacement of various flat panel displays is simply jaw-dropping. . Emerging display technologies based on LCD (liquid crystal display), PDP (plasma display), DLP (digital optical processor), LCoS (liquid crystal on silicon), show the development direction of TV technology, among which LCD, PDP and DLP has also become the mainstream configuration of home theater. Projection TVs based on LCD and DLP technology are even more diverse, with both front and rear projections, both single and three. Major domestic and foreign manufacturers are competing to launch new models.

Like a movie machine, an orthographic TV can be regarded as a slide projector for picture activities. An orthographic TV used for conferences, teaching, and publicity is also called a "projector." The rear projection TV is the same as the shadow play. It can be understood as an "automatic shadow player", but it is not necessary for the shadow play artist to toss behind it, and you can also use the remote control to call the play team at will. But if the play is good or not, it depends on the audio configured for it.

The emergence of new displays has brought us a whole new enjoyment, especially orthographic projection. This kind of "projection" looks really like a cinema.

It can be said that at present we are in a new era of "big explosion" in the variety of Video products, and the home appliance market has provided us with too many choices at once. This point, even many "industry people" will feel overwhelmed. The knowledge is updated too quickly, some of which have been used for decades, and well-known nouns (such as "progressive scan", "magnetization", etc.) will soon be abandoned!

In addition to the excellent performance of these novel products, their use and configuration are also very different from those of color TVs in the past. Whether they can see good images or not, it does not cost thousands of dollars. It can be solved by "carrying the big TV home".

Faced with such a dazzling array of products and various tempting technical indicators, it is even more necessary to have a more reasonable configuration plan from the beginning, taking into account the room size, shape, lighting and lighting conditions, as well as the consumer's personal Preferences, main content to watch, consumption level and other factors, many professional new concepts and new knowledge involved, if these factors are not fully taken into account, it will not be easy to achieve the desired effect, resulting in de facto "degraded use", And "resource waste".

Audio will make a comeback

Audio and Video are both essential for audiovisual entertainment.

The great progress of Video will inevitably raise higher requirements for Audio. As far as the current audio products are concerned, after analysis, the author believes that there are two major problems that hinder its development and even the market shrinkage.

The first is the issue of technical indicators.

So far, the audio technology has not even solved such a basic problem as frequency response. When it comes to this, many friends will disagree and think that this is not a problem at all. It has been solved long ago. Look at the product promotion of the merchant, from 20Hz to 20kHz Is n’t it all included? Besides, it ’s just that there are fewer “twenty hertz”. Compared with the nearly 20,000 “hertz”, what impact can it have!

It should be pointed out that as the home theater technology, the "soul" of its audio is reflected in the subwoofer part, which is from 20Hz to 40Hz. Although digitally covering only the range of 20 Hz, they are listening. Psychologically covers a whole "octave", which is what we often say an "octave", it is these 20 "Hertz", but it has become the biggest difficulty since the birth of the speaker.

Some speakers are made as large as refrigerators. It is not uncommon for the speaker unit to have a diameter of more than 15 inches. The power of a home audio amplifier has also achieved several hundred watts. What is the reason? There is a reason for obtaining a subwoofer! Even so It is still difficult to extend down to 20Hz, which means "the depth of the dive is not enough". In a sense, subwoofer is not only impossible but also very “luxury”.

To this end, a "0.1 channel" was set up in the home theater, dedicated to playing subwoofers, and the corresponding product is an active subwoofer.

In the audio field, the "enable" of the subwoofer is a big improvement, because its proper use, the contrast of the atmosphere, is very strong for the sense of shock. It is impossible to imagine that in a high-end modern cinema, there is no such thing in a large film.

In order to obtain valuable subwoofers, engineers thought of many methods, such as the use of electronic crossovers, sound resonance and ultra-high power, expensive ultra-long stroke speaker units and other extreme measures on the subwoofer, in order to get a little more "Bass dive".

Even if this is done, due to the low design level, or due to cost constraints, it is difficult for the subwoofer to "dive" down in most audio products, so what we actually see is that many subwoofer products cannot even dive By 40Hz, the meaning of the subwoofer is lost, and it can only emit frequencies of subwoofer (40Hz ~ 80Hz) and above, and the distortion is very serious. It is not as good as a "regular design" floor speaker. Using such a cannon to add sound replay, called blinding, can only add chaos.

Unqualified subwoofer products and irresponsible (or even fraudulent) advertising have caused consumers to have a bad impression of the audio in the home theater, especially against the subwoofer.

The second is the listening environment.

This is an old problem that has troubled the audio industry for decades, but in fact it has not been paid enough attention. It has become particularly prominent in home theaters because the sound pressure required by home theaters is relatively high, and the bass dive is also deep. . The high sound pressure caused the overall increase in the intensity of various "extra" sounds including reflection, which fully exposed the existing environmental defects of insufficient sound absorption, and the originally less obvious reverberation and standing waves became very serious. Watching movies or listening to music in this way of listening is not so much "enjoyment" as "suffering".

Many of the friends I contacted, including those with "fever", from their listening environment, this problem is very serious, and often not paid attention to, because there is not a correct understanding. They are often more willing to discuss the upgrade of equipment, but in fact that cannot solve the fundamental problem.

Another limitation of the listening environment for home theaters is the problem of "sound insulation". For fear of harassing neighbors, the sound is usually very low, and even headphones are used.

This situation often leads consumers to reflect on: what is the use of these Laozizi audio?

In this way, Video seems to have the meaning of "throwing away" Audio?

The above analysis is just the author's opinion. In fact, there are many factors that affect the market and consumer behavior, such as the overall change in the purchasing power of consumers, the diversification of consumption and so on. As a manufacturer, it should be dedicated to making its own products, less impetuous and more honest in marketing.

Fortunately, with the advancement of technology, some subwoofer products that can achieve the subwoofer playback index have entered the market. Although the price is relatively expensive, there are indeed many enthusiasts who have described them excitedly "heard the real super bass".

On the other hand, the "new concept of home audio-visual entertainment" is gradually being accepted by people. This concept advocates the consideration of the audio-visual room environment and audio-visual equipment as a whole. That is to say, the "trinity of audio-visual entertainment, Audio, Video and environment" "It is indispensable, we have to take into account in order to achieve better results. Among them, the" relationship "between Audio and the environment is particularly close. When the environment is handled well, Audio will not only eliminate people's misunderstandings, but its status will be greater Promotion.

The big waves are scouring the sand, the market is changing, and the consumer behavior is changing. The only constant is that people's health needs for visual and auditory enjoyment are constantly increasing.

In a foreseeable future, Audio will rise again, but it will be more scientific and more standardized.

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