The so-called Hi-Fi refers to "specially researching the technology of recording and reproducing the original sound signal with the most realistic fidelity, as well as the audio equipment and related technical testing methods and instruments used for this." In addition, the so-called maximum fidelity does not rule out some necessary modifications and beautifications (such as removing noise from live recordings and retaining only some applause and cheers). However, some people have different opinions on the beautification of sound. They believe that high-fidelity is to reproduce the original signal faithfully without distortion, without any distortion or adding anything, that is, to maintain the original flavor.
However, people have achieved a relatively unanimous agreement on the following technical features that high-fidelity should have:
(1) Wide frequency response range: It was once thought that the human ear's listening range was from 50Hz to 15Hz, and that was also the requirement for sound recordings and sound reproduction facilities at that time. Later, as technology progressed, the audible range of the human ear was expanded, that is, from 20 Hz to 20 kHz. However, currently not all audio equipment can achieve such a wide frequency response range, not only is it required to have such a wide frequency response range, but also at any frequency that is not within the frequency response range, playback must not be applied or reduced. Any point of the original sound, of course, is an ideal situation after all.
(2) Large dynamic range: High-fidelity audio equipment must be low-noise. When the system is performing sound reproduction, a large dynamic range will be generated between the maximum loudness and the lowest background noise, that is, the dynamic range. At the same time, high-fidelity sound recordings require recording production without compression (that is, without changing the level of the lightest and strongest loudness music passages) in order to maintain the dynamic range of the original sound.
(3) Low noise: It is a parameter of dynamic range, but it is often listed separately in the technical indicators.
(4) Low distortion: In a broad sense, distortion refers to any kind of change to the original sound signal. There is no distortion-free audio equipment. Even the most perfect audio equipment will still make some changes to the original signal in some aspects. Usually total harmonic distortion (THD) and intermodulation distortion (IM) are used to represent distortion. The distortion index of modern audio equipment has been digitally low to an unbelievable level, such as a few thousandths or lower. However, what is puzzling is that some Hi-Fi speakers with quite good performance have distortion as high as 80%. It seems that there are still some differences between the technical indicators and human hearing experience, and the technical parameters cannot fully explain the problem.
(5) Moderate power: Power is an important indicator when purchasing a power amplifier. Even if the power value is specified according to the most stringent standard, the power of the power amplifier is still indirectly related to the loudness of the complete set of audio during sound reproduction.
Finally, we try to make some more precise definitions of Hi-Fi. Of course, we should first understand that it is incomplete and inappropriate to use certain technical indicators to define Hi-Fi. In addition, it seems that it is unfair and biased to judge the level of Hi-Fi solely by sound effects. So instead of using technical parameters to define Hi-Fi, I try to explain Hi-Fi from the perspective of music.
The so-called Hi-Fi audio device refers to the sound reproduction, after making every effort technically, in addition to preserving the melody, rhythm and charm of the music, it is also necessary to retain as much as possible the exciting and exciting parts of the music. Fascinated, even want to make people dance with music connotation audio equipment.
As a music and audio enthusiast, it is okay to play with audio, but it must be modest, according to your own conditions and within your ability. This is because any audio equipment, whether it is an analog circuit or a digital circuit, whether it is expensive or cheap, is just a tool for sound reproduction, and it serves us to enjoy music. Listening to music is the goal, while audio equipment and CD records and other software and hardware are the means. Don't put the cart before the horse or put the cart before the cart.