1. Monophonic
Monochannel is a primitive form of sound reproduction, which was widely used in early sound cards. When playing back mono information through two speakers, we can clearly feel that the sound is transmitted to our ears from between the two speakers. This kind of recording method, which lacks a sense of position, is naturally very backward from the current point of view, but when the sound card just started, it was already a very advanced technology.
Stereophonic sound
Monochannel lacks sound localization, and stereo technology has completely changed this situation. In the process of recording, the sound is distributed to two independent channels, thus achieving good sound localization effect. This technology is particularly useful in music appreciation, and the audience can clearly distinguish which direction various musical instruments come from, thus making the music more imaginative and closer to the live experience. Stereo technology has been widely used by a large number of sound cards since Sound Blaster Pro and has become a far-reaching audio standard. Today, stereo is still the technical standard followed by many products.
3.quasi-stereo
The basic concept of quasi-stereo sound card is to use mono when recording, stereo sometimes and mono sometimes when playing back. Sound cards using this technology have been popular in the market for some time, but now they have disappeared.
4. Four-channel surround
People's desires are endless. Although stereo meets people's requirements for the sense of position of left and right channels, with the further development of technology, people gradually find that dual channels can no longer meet our needs. In the first part of the topic, the author mentioned that the broadband of PCI sound card has brought many new technologies, among which the fastest development is three-dimensional sound effect. The main purpose of three-dimensional sound effect is to bring a virtual sound environment to people, and to create a realistic sound field through special HRTF technology, so as to obtain better game auditory effect and sound field positioning (which will be introduced in detail later). To achieve good results, it is far from enough to rely on only two speakers, so stereo technology is stretched in front of three-dimensional sound effects, and the new four-channel surround audio technology solves this problem well.
Four-channel surround defines four pronunciation points: left front, right front, left back and right back, and the audience is surrounded in the middle. At the same time, it is suggested to increase bass speakers and strengthen the playback processing of low-frequency signals (this is also the reason why the 4. 1 channel speaker system is widely popular now). As far as the overall effect is concerned, the four-channel system can bring sounds from many different directions to the audience, and can get auditory feelings immersed in various environments, giving users a brand-new experience. Nowadays, four-channel technology has been widely integrated into the design of all kinds of high-end sound cards, which has become the mainstream trend in the future.
5.5. 1 channel
5. 1 channel has been widely used in various traditional theaters and home theaters. Some well-known sound recording and compression formats, such as Dolby AC-3 (dolby digital) and DTS, are based on the 5. 1 sound system. In fact, the sound system of 5. 1 comes from 4. 1 surround, but the difference is that a central unit is added. This central unit is responsible for transmitting sound signals below 80Hz, which helps to strengthen the human voice when enjoying the film and concentrate the dialogue in the middle of the whole sound field to increase the overall effect. I believe that every friend who has really experienced Dolby AC-3 sound effects will be deeply impressed by 5. 1 channel.
Don't think that 5. 1 is the peak of surround sound, and the more powerful 7. 1 system is ready to try. On the basis of 5. 1, two pronunciation points, center left and center right, are added to achieve a more perfect state. Of course, due to the high cost, it will take some time to popularize it, so I won't introduce it here.
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