What kind of digital media player is HIFI level?

                             What kind of digital media player is HIFI level?

1. The core of HIFI player: audio DSP.

   
   

Without a good DSP, good sound is out of the question. What is a good DSP? It's very simple: hard solution, high speed, at least work at a frequency above 300M, and ensure real-time performance.

Why is hard solution better than soft solution? Everyone understands the structure of the CD player. The CD player reads the signal from the CD, and after being amplified, it directly enters the DSP for EFM decoding, de-interleaving and other processing processes. These are all completed by hardware, a purely physical process, and the delay of signal processing is equal, so it has high signal processing. quality. Although the format of the CD player is low, the analog signal is restored from the master tape, and then after format conversion and frequency reduction, it has undergone encoding, engraving the master disc, making a master disc, pressing the disc, reading the signal with the optical head, amplifying the signal, decoding and interleaving , and a series of complex processes, it can still achieve high performance, and it is still difficult to be replaced today, and it can defeat many "HI-END level" "mastering file players", relying on this unique skill: Hardware solutions!

Some "mastering file players" use ARM chips as DSP, and realize audio signal processing through software algorithms, which will occupy CPU resources. The CPU works in time-sharing. While performing signal processing, it also needs to manage and read peripherals. In addition, the CPU performs calculations, and the complexity of calculations will also change due to signals. These uncertain variables will inevitably make audio The lack of coherence in signal processing is the biggest criticism of the soft solution, and it is also the main reason why the player of the soft solution solution is difficult to HIFI.

Some digital player solutions have the ability to decode WAV, and even FLAC, which seems good, but another important capability is not available, please see below:

2. The soul of the HIFI player: the clock system.

The clock is the blood of digital circuits, and in digital audio, it is the soul of sound quality!

Why is DVD no matter how it is done? It is difficult to compare with CD, and the clock is a major factor. The clock of DVD is a 27M crystal oscillator, which is designed for video, and the clock needed for audio is divided from it. Because 27M is not an integer multiple of the audio clock 44.1K or 48K, frequency division will produce errors. It is this error that keeps DVDs at the consumer level forever.

Like DVD, many digital playback devices on the market are designed according to the consumer level, without considering the niche needs of HIFI, and their audio clocks are all frequency-divided from a clock source. Such a playback solution, even if a sky-high DAC is used at the back end, cannot make up for the signal deviation caused by the front-end clock error.

The best clock system architecture is: an independent audio clock directly enters the DSP, and the audio clock is directly used as the system clock MCLK without any frequency division processing. Considering that there are two types of frequencies in digital audio files: 44.1K series and 48K series, there must be two frequency audio clocks for selection. If there is only one clock, the player is incomplete.

The current market situation is: only a few brands can develop CPUs using external independent dual clocks, and the general digital playback solutions do not have the ability to use external dual clocks. Those "HIFI players" and "HIFI Blu-ray players" are only used A consumer-level player solution, just add a HIFI-level DAC, its meaning is equal to DVD+HIFI decoder.

The CD machine can defeat the "master tape player", but also rely on another unique skill: an independent dedicated audio clock directly into the DSP! With these two unique skills, CD players can survive in the market for a while.

3. How to identify the HIFI player

It's very simple: look at the architecture, whether it is a hard solution, whether it is an independent DSP, and whether it is high-speed. The last "high speed" is also critical, because the current 24bit/192K signal has a code rate of nearly 10M, which is 7 times larger than the 1.4M of the CD player, and the hardware requirements are much higher than the DSP in the CD era. Second, look at the clock. HIFI-level players must have dual clocks, generally 11.2896M+12.288M, or 22.5792M+24.576M. If this condition is not met, this player, even if it is connected with a high-end DAC, can only be classified as a consumer-grade product. This is very easy to do, just open the cover and look at the configuration of the crystal oscillator at a glance.

Hardware DSP+external dual clock requires modification and development of the CPU. Chip-level development is not a small investment, and HIFI companies generally cannot bear it, so they have to use the opportunistic method of consumer-grade solutions + DAC, which also makes the current HIFI digital player market mixed with fish and dragons.

Digital media players are products with a certain level of technical content. When choosing a player, you should not just rely on the sense of hearing, nor be confused by those high-sounding, artistic titles. There is a qualitative difference between digital products and analog products, relying on a hard-earned technical foundation. Only on this basis can it be meaningful to talk about the sense of hearing.