Those Hi-Fi cold knowledge you don't know!

                                     Those Hi-Fi cold knowledge you don't know!

When it comes to Hi-Fi, you may think of audio enthusiasts, CDs, vinyl records, Hi-Fi speakers, Hi-Fi headphones, etc. The prices of all playback devices or records related to hifi are also high. But when you are asked one day what is Hi-Fi, you may be confused!

In fact, Hi-Fi is the abbreviation of High-Fidelity. Translated into Chinese, it means "high-fidelity". In the audio industry, high-fidelity refers to the process of restoring the height of the sound to the audience! In this process, our main concern is the restoration of sound! So how can we restore the sound perfectly?

First we need to determine the playback source! Such as lossless audio files, vinyl records, cds, dvds, tapes, etc. We can roughly divide the playback source into two categories, one is the recorded analog signal (that is, the vibration of the sound is directly recorded, the real physical vibration process is recorded, and it is recorded linearly), such as vinyl records , magnetic tape, steel wire of a steel wire recorder; the other type is recorded digital signals (converting linear analog signals into digital signals by sampling in unit time, which is non-linear recording), such as wav audio files, mp3 audio files , cd and so on. The playback source for recording analog audio signals is like the negatives used when developing photos in the past, and the playback source for recording digital audio signals is like photos saved on mobile phones now. There is no good or bad between the two. If there are two playback sources with the same sound quality and different recording methods, analog is basically more expensive than digital, such as vinyl records and CDs, and vinyl records are basically more expensive than CDs.

Once the playback source is determined, our "hifi restoration" work will be easier to carry out!

Around us, most audiophiles will still choose lossless audio files as the playback source, and very few local tyrants will choose vinyl records or tapes as the playback source. If you choose lossless audio as the playback source, then during the entire restoration process, the audio signal needs to undergo a digital-to-analog conversion (digital sampling is converted into an analog electrical signal). High, the greater the bit depth, it may contain more sound details, which intuitively reflects the larger the size of the audio file in front of you, so we try to choose a larger file to play when playing, and the quality may be lower Better, the common lossless audio formats are wav, flac, ape, we had better choose lossless audio files in wav format to play during playback, because flac and ape are re-encoded and compressed on the basis of wav to save storage The advantage of this is that the file is smaller, and it is also a lossless audio format, but flac and ape consume more computing resources during playback, and some audio information may be lost during the decoding process in order to maintain smooth playback.

Find a wav lossless audio file, and then you need to decode the audio file. In the process of audio decoding, we need to use a decoder, which is the legendary sound card! Now most of the sound cards on the market can not only convert digital audio signals into analog signals, but also convert analog signals of microphones or other musical instruments into digital signals, so sound cards are also called audio interfaces, responsible for audio AD/DA conversion, A It is Analog (referring to analog signal) and D is Digital (referring to digital signal). If we only use it to restore audio files, we will only use the DA function of the sound card. Some audiophiles also call it DAC (Digital to Analog Converter). You are choosing DAC At the time, the higher the various parameter indicators, the stronger the reduction ability of the DAC, and of course the more expensive the price. I will not list the specific parameters one by one. The products produced by various manufacturers are basically explained on the official website. You can read the manual when purchasing.

After the audio file passes through the DAC, it needs to use AMP (Power Amplifier, referred to as: Power Amplifier) for one-step amplification to a volume that we can hear clearly. This step is an amplification of a pure analog signal, which is the most annoying in the amplification process of analog models. The most important thing is the low noise of the analog amplifier (also called low noise, which is generated by the circuit of the analog device during the amplification process. This noise can be made very small but cannot be completely avoided at present). From the point of view of the amplification principle of the circuit, the best amplification quality is Class A power amplifier, followed by Class D. However, with the continuous innovation of technology, Class D power amplifiers are advancing by leaps and bounds, almost comparable to Class A power amplifiers, but perfectionists It is recommended to choose Class A power amplifier first. Although Class A power amplifier has a small magnification, high heat generation, and low conversion efficiency, it sounds good! The status of this sense of hearing in the hearts of the majority of audiophiles is almost unshakable. (The class D power amplifier I bought, maybe I am not a qualified audiophile, or maybe I am poor)

The signal amplified by the AMP (power amplifier) can be directly sent to the Speaker (speaker). The matching between the speaker and the power amplifier also needs to consider many factors, such as the amplified frequency response range of the power amplifier and the restored frequency response range of the speaker. If the normal amplification of the power amplifier The frequency band is 20Hz-20kHz, but you are equipped with a speaker with a restored frequency response range of 50Hz-16kHz, then the restored sound will be missing 20Hz-50Hz and 16kHz-20kHz. But if you match the same power amplifier with a speaker with a restoration frequency response range of 20kHz-35kHz, your speaker will not be able to reproduce sounds higher than 20kHz. In addition to the frequency response range, a series of parameters such as sensitivity, impedance, power, etc. need to be matched as much as possible to jointly build a high-quality hifi system.

So those who have no experience or don’t want to bother, you can directly consider using active speakers to solve this pain point. The manufacturer directly matches all the parameters for you, and integrates the power amplifier and the speaker to sell it to you. All you need to do is Enjoy music and enjoy life.

As for those fans who use vinyl records and tapes as playback sources, they only need to consider vinyl record players (referred to as: turntables) and tape players during the entire hifi restoration process, and then output the analog signals directly to the power amplifier. It is amplified and finally converted into a sound signal that our human ears can receive through the speaker. The sound restored in this way can be regarded as linear amplification in the true sense, because from the playback source to the speaker, the audio signal is always in a pure analog state, which interprets the meaning of high fidelity to the greatest extent!