The history of tape recorders

The earlier tape recorder was called the phonograph, which was born in 1877. It was invented by Edison, the world famous inventor. Edison made use of the phenomenon that the diaphragm in the telephone transmitter vibrates with the sound, and made an experiment with a short needle, from which he was greatly inspired. Speech speed can make the short needle vibrate accordingly. Then, in turn, this vibration will certainly make the original sound. So he began to study the problem of sound reproduction. 1877 On August 5, Edison asked his assistant Chris to make a strange machine consisting of a big cylinder, a crank, a receiver and a diaphragm according to the pattern. Edison pointed to this strange machine and said to his assistant, "This is a talking machine." He took out a piece of tin foil and rolled it on a metal cylinder engraved with spiral grooves. One end of the needle gently rubs the tin foil, and the other end is connected to the receiver. Edison shook his crank and sang, "Mary has a little lamb, like a snowball …" to the receiver. After singing, put the needle back in place and gently shake the handle again. Then, the machine slowly turned round and round, singing "Mary has a little lamb …", just like Edison just sang. When the assistants nearby met a talking machine, they were too surprised to speak.

The news of the birth of "talking machine" caused a sensation all over the world.

/kloc-from 0/877 to 65438+February, Edison performed the phonograph in public, and was immediately praised by the public as "scientific Napoleon", which was one of the three most exciting inventions of 19 century. The upcoming Paris World Expo will immediately put it on display as a new exhibit. Even so, US President Hayes walked around the phonograph for more than two hours.

10 years later, Edison improved the large cylinder and small crank on the phonograph into a device similar to a clock mechanism, and the phonograph was widely popularized by driving a thin wax plate with a motor.

Although Edison invented the phonograph and realized recording. But at that time, the tape recorder mainly used mechanical principles to reproduce the sound. The sound volume recorded by it is very low, so you need to shout at the speaker when recording. In order to improve this recording method, Danish scientist Paulson began to try to use the principle of telephone transmission to store sound magnetically. Paulson experimented with steel wire. Under the action of magnetic force, the steel wire will become a magnet. After the magnetic force disappears, the steel wire in the magnetic field will remain magnetic. This residual magnetism is called remanence. Paulson wound a long steel wire around the reel. The steel wire is connected to another reel through an electromagnet, and the recording microphone is connected to the coil of the electromagnet. In this way, the electrified electromagnet turns the electromagnetic signal in the telephone receiver into a magnetic field, and the steel wire in the magnetic field is magnetized to produce remanence that varies with the sound, and the sound is recorded on the steel wire. Because this kind of magnetic recording uses high-quality steel wire and steel belt, and it is cumbersome and inconvenient, which affects the popularization of this recording method.

Marvin Kamras, an American radio enthusiast, played a key role in popularizing tape recorders. When he was studying the problem of recording signal damage, he came up with the idea that the surface magnetism of steel wire would never change. If the sound can be recorded evenly on the surface of the steel wire, won't you get a uniform sound signal? At that time, the principle of the tape recorder was to use the metal pointer as the recording needle to contact the surface of the steel wire, so that the steel wire at the contact point between the two was only magnetized, resulting in the phenomenon of unbalanced recording. Kamras wants to use a magnetic head to improve it, that is, a complete magnetic ring is used as the magnetic head, the steel wire passes through the magnetic ring and keeps the distance between them, and then the air gap around the steel wire is used for recording. Compared with the former, the improvement of Kamras is that the air gap is used to replace the metal pointer in the recording process, which avoids the damage to the magnetic signal.

The real popularization and practical application of tape recorders came after the invention of magnetic tapes. 1935, the German scientist Lao Ma also invented magnetic tape instead of steel wire. This kind of adhesive tape is based on paper tape and plastic bag. The bottom of the tape is coated with a layer of iron powder called ferroferric oxide and bonded together with a chemical colloid. This kind of adhesive tape is not only light in weight, but also tough and easy to cut. Subsequently, Frayema coated iron powder on paper bags instead of steel wires and steel belts, and succeeded in 1936. Paper tape is cheap and easy to carry, which is recognized and accepted by people. Inventor Kamras is not far behind. At the end of World War II, Kamras discovered a magnetic particle, which is iron oxide powder. He mixed the powder with varnish or still water, and then coated it on paper tape and paper tray. When the paint is wet, put it into a magnetic field, and all the particles will be arranged in a certain direction under the action of the magnetic field. This is the embryonic form of modern magnetic tape. It is said that Valdemar Poulsen, a young Danish engineer, made a "tape recorder" with piano wire by using the principle of magnetic variation, and obtained a patent in 1898, which is the predecessor of 1930 steel wire recorder. Paulson exhibited his tape recorder at the Paris World Expo in 1900. Although the famous singer's recording cartridges were sold earlier, scientists are still interested in tape recorders. Emperor Franz Joseph left a dialogue, which became the earliest existing magnetic recording data. Emile berliner, the inventor of the disc phonograph, set up a factory to produce machines in the United States in the same year. Paulson also wants to follow suit, but the funds are insufficient. Finally, the factory fell into the hands of businessman Charles Rudd. Rude, who has a business mind, recorded the conversation of the President of the United States with a tape recorder, and helped the new york police to solve the triad murder case, making the tape recorder famous. The German Navy purchased several tape recorders for use by ships passing through Denmark. During World War I, they used them to record Morse code, which led Germany to sink an American troop carrier. After the war, Rudd was accused of treason, but he was still involved in the lawsuit until his death in the 1990s. This is a "spy rumor" in the history of the recorder.

After the Germans tasted the sweetness, they began to study magnetic recording. 1927, Fritz Froehmer successfully coated powdered magnetic substance on paper tape or adhesive tape for recording, hoping to replace the wire tape recorder at that time. At that time, the British BBC used a giant Blattnerphone steel recorder improved from a tape recorder. This tape recorder can cut the steel strip and weld it again for editing, but there is always a lot of noise at the welding point, and when operating, it is afraid that the welding point will break and the steel sheet will fly, so the tape developed by the Germans is safe and ideal. 1932, the famous BASF successfully developed mass-produced tapes. They cooperated with AEG, the largest motor manufacturer in Germany, and hoped to launch the "Magnetophon" magneto-acoustic machine at 1934 Berlin Radio Exhibition. BASF first made 50,000 meters of tapes, which was an amazing achievement before plastic materials were widely used. 1936, the British conductor Sir John Biqin led London Philharmonic Orchestra to visit Germany. At the invitation of BASF, he gave a performance in ludwigshafen Concert Hall on June 1 19, including Mozart's Symphony No.39, which was the first large-scale magnetic recording in the history of music. On the other side of the Atlantic, stokowski, the conductor of 193 1, and the long recording of 33 1/3 demonstrated by RCA in the same year were recorded directly on wax discs. Americans also study magnetic recording. For example, Marvin Camras introduced AC bias technology into a wire recorder, making its bandwidth and noise reach the level of recording music. Another brush company has also developed audio tapes. They asked 3M Company to make a thin tape, which has a smooth surface and a thickness of three thousandths of an inch, is soft and moisture-proof, and can be coated with magnetic iron powder. These specifications have been used for 30 years, but the Soundmirror designed by Brush has not formed a climate.

During World War II, German radio stations began to widely use tape recorders to play recordings of important military generals. Americans often wonder why Hitler was in several places at the same time. It was not until after World War II that the first tape recorder used in the recording studio in the United States was finally born. However, there are some difficulties in promotion. Why didn't Marin invite the radio program hosted by pop star Ping crosby to try it? In the summer of 1947, the tape recorder provided by Ampex came in handy. Ping Crosby is very satisfied with the tape recorder which is easy to assemble, so he plans to switch to the tape recorder from autumn. However, the engineers were afraid, and they carved the contents of the tape on the record and then played it on the record. It lasted for more than half a year, but I didn't expect this to be the standard mode of music record production later. Ampex's tape recorder uses the entire width of the tape, records it once in one direction, and then rewound it after each recording. This method is called full tracking. Soon, a half-track recorder appeared, which only used half the width of the tape at a time. After recording, you can record it again in the opposite direction, and the time is doubled. Hey! By the way, since two tracks can be used, two different signals can be recorded. 1949, Magnecord Company of the United States developed a two-channel stereo recorder, which was nearly ten years earlier than the first commercial stereo record. With the stereo recorder, new york WQXR Radio Station started stereo FM broadcasting at 1952, and Audiosphere also released the first commercial stereo tape at 1954, which officially entered the stereo era and indirectly promoted the development of stereo records. On the basis of tape recording, Ampex successfully developed a color video recorder in 1953, and dominated the market in the next 20 years.

Since then, tape recorders have entered the Warring States period and ordinary American families. Although the effect of disc recorder is good, it is not easy for an old man to wind the tape around many rollers and install it correctly. Later, George Eash, an inventor in Cleveland, put a five-inch tape into a plastic box and added some rollers and guide rods to make it easy to use, even in a bumpy car. The invention of Eash is what we call "cassette tape". Eash's initial difficulty was that the time was too short, only 30 minutes. Later, after continuous improvement, I can record music for an hour. 1963, Earl Muntz further improved the design of Eash, which was widely used in automobiles and ships. In addition, Muntz used a four-channel recording head in the cassette recorder, which was originally intended to extend the playing time, but later unexpectedly became an excellent storage device for four-channel audio. Until the end of 1970s, the cassette player named Fidelipac still had many supporters, forming a special music culture. The future development of cassette tape recorder revolves around the accuracy and material change of magnetic head, the improvement of magnetic tape and noise suppression technology. For example, the glass magnetic head developed by Akai in Japan is famous for its wear resistance and good sound; The precision magnetic head developed by Nakamichi has a bandwidth of 20 Hz-20 Hz when it first reaches ordinary magnetic tape. Chromium dioxide was used instead of iron oxide, and even cobalt and nickel were used as magnetic materials. The noise suppression system has been improved from Dolby B and C to Pro HX, with satisfactory dynamics and bandwidth. Appreciating the most advanced cassette tapes almost feels like LP records, which digital tape recorders lack.

Digital tape recorder, headed by DAT, works like a video recorder, recording signals on the tape with a high-speed rotating head. It can be said that it is the biggest breakthrough in the development of tape recorders in the past 80 years. Unfortunately, DAT is so effective that even with the anti-copy device, all software manufacturers are still afraid that it will cause the proliferation of pirated music, so they strongly resist it. Finally, DAT can only stay in the recording studio to serve a few people.