What types of audio speaker basic knowledge do you have?
1. The history of sound technology. The development history of audio technology can be divided into four stages: electronic tube, transistor, integrated circuit and FET.
In 1906, American DeForrest invented the vacuum triode, which pioneered the human electroacoustic technology. After Bell Laboratories invented the negative feedback technology in 1927, the development of sound technology entered a new era.
The more representative amplifiers, such as the "Williamson" amplifier, successfully used the negative feedback technology, which greatly reduced the distortion of the amplifier.
By the 1950s, the development of tube amplifiers had reached a climax, and various tube amplifiers were emerging one after another. Because the tone of the tube amplifier is sweet and mellow, it is still preferred by enthusiasts.
The appearance of transistors in the 1960s made the vast number of audio enthusiasts enter a broader audio world. Transistor amplifier has the characteristics of exquisite voice, low distortion, wide frequency response and dynamic range.
In the early 1960s, the United States first introduced integrated circuits, a new member of sound technology. By the early 1970s, integrated circuits were gradually recognized by the sound industry because of their high quality and low price, small size, and multiple functions.
So far, thick film audio integrated circuits and operational amplifier integrated circuits have been widely used in audio circuits.
In the mid-1970s, Japan produced the first field effect power transistor. As the field effect power tube has the pure thick and sweet voice of the electronic tube, and its dynamic range reaches 90dB, THD<0.01% (at 100kHz), it soon became popular in the sound industry. Nowadays, many amplifiers use FETs as the last stage output.
The development of sound technology has gone through the historical period of electron tube, transistor and FET, and has its own characteristics in different historical periods. It is expected that digital audio technology will be the mainstream of audio technology in the future.
Introduce the specific meaning of dB
The unit dB is widely used in electronics. It is a relative unit for measuring and comparing the power, voltage and current of a system. Later, due to the progress of science and technology, it was recognized that human response to sound changes according to the logarithmic law.
So there is a unit: Bel is the name of the inventor of the telephone. Its expression is: Bel=lg (P/Po) P is the measured power Po is the reference power; Bel represents the logarithm with the base of 10.
In fact, it is found that Bel is too big, so we take its tenths as a new unit, that is, decibels (dB) divide Bel by 10, that is, dB expression is: dB=10lg (P/Po), dB=20lg (E/Eo), dB=20lg (I/Io)
2. What is Hi Fi? What kind of audio equipment is Hi Fi?
Hi Fi is the abbreviation of English High Fidelity, which is literally translated as "High Fidelity". It is defined as a playback sound that is highly similar to the original sound. So what kind of computer surround sound speakers audio equipment playback sound is Hi Fi?
So far, it is still difficult to draw a definite conclusion. Professionals in the audio industry use various instruments to detect various indicators to determine the degree of Hi Fi, while audiophiles often use their ears to judge whether the equipment creative speaker meets their expectations.
To judge the high fidelity level of the playback sound, not only the equipment and software with excellent performance, but also a good listening environment are required. Therefore, there are differences between objective testing and subjective evaluation on how to correctly measure the Hi Fi level of speaker sounds audio equipment.
