About "how to do big with little money" to build a high-quality, low-cost desktop HiFi system. I'll admit that we're talking about a topic that may have been familiar to veteran players for a long time, and outsiders may seem confused, but I'm confident that everyone will get something out of it.
Choosing a pair of high-performance and appetizing headphones, paired with a set of high-quality decoder amps, is a complete HiFi system for most people. If we are willing to spend money to improve the quality of power supply and come up with carefully prepared high-definition audio sources, then we are not far from tapping all the potential of the equipment in our hands. However, as the saying goes, "those who travel a hundred miles are half ninety", the interference of the sound source on the digital end is still not negligible. According to the barrel principle, this is actually the last shortcoming that needs to be filled.
As a standard answer, although these digital signals can be efficiently processed and purified, their prices are usually thousands of yuan, and some will even sell for more than 10,000 yuan. When you take it apart, it looks like a small computer/tablet that has been customized by HiFi, with a high-quality power supply. Since the finished data broadcast is similar to the brand computer, it is completely possible to save a set of high-quality "data broadcasting" with DIY thinking, and even achieve richer functions through open operating systems and software. However, the USB interface used for output is also responsible for power supply, with many contacts, a wide variety of protocols, and complex signals, and the interference of data in it is naturally large. Due to its relatively simple function and relatively pure signal, the network port is naturally suitable as a transmission medium for HiFi data. In addition, because various streaming software can bypass the system interface, realize the separation of the bridge core, and write data directly from the network terminal or external hard disk into the player's cache, which is equivalent to bypassing various interference from external intermediate links. This is the ideal state that burners are looking forward to.
As a result, many bridges, as well as all-in-one machines with their own bridges, came into being. However, the characteristics of network signals are different from those of USB signals, and the entire process from signal shaping and conversion to clock alignment needs to be specially designed. The quality of decoding the headphone amplifier is the focus of attention of burners. An all-in-one machine with an integrated good experience bridge and high-level decoding headphone amplifier can save a lot of trouble for those who like it. All of the above coincides with Yulong's idea, so there is ASURA, a local clock synchronous webcast, equipped with a sixth-generation low-jitter digital signal processing module optimized for webcasting and digital broadcasting, and the mainstream AK4191+ AK4499EX decoding chip, plus inherited from the flagship DA1, without shrinking the headphone amplifier circuit. It is equivalent to pouring the foundation of the HiFi system solidly, and the price is not much more expensive than the mainstream decoding headphone amplifier such as DA11. As long as you pay more attention to the NUC (small computer), switch, and power supply, it is enough to assemble a set of cost-effective HiFi preamplifiers with far more effects than the investment, and try to give full play to the upper limit of the headphones in your hands.
ASURA is about the size of an A4 piece of paper, and the top layer is just right for a NUC and router. As for whether the lower layer wants to add isolated/regenerative power supply, it is rich and frugal, and the whole set does not take up space. Compared with those who only have a decoding function, or have a small load capacity, and need to purchase a separate post-amp for digital broadcasting, ASURA can not solve it whether it is pushing large ears or speakers, so building a system around it not only saves money, but also saves valuable space.
When I first got my hands on this machine, I almost couldn't tell the difference between ASURA and DA11, whether it was the layout of the front face of the machine, or the interface layout on the back was exactly the same as DA11. At a glance, it's an ordinary decoder with coaxial, optical fiber, and USB interfaces, until I found the new RJ-45 Gigabit Ethernet port behind the fuselage, and the fairly thick manual in the box. Playing webcasting requires a certain learning threshold, and it is also a process to familiarize yourself with ASURA's menus and bridge functions, and it is also a good idea to familiarize yourself with the instructions before experiencing them. Anyway, I recommend double-clicking the volume knob to enter the secondary menu, and turn on all the options in the secondary menu: AirPlay, DLNA, Roon, and HQPlay. The network is set to "Automatic", connect the router and wait for the machine to automatically recognize the IP address. When you're ready to stop, you can use its streaming feature.
The so-called streaming is actually the download URL of the data stream from the cloud directly through software, or pushed to the decoded headphone amplifier from the local storage device. The advantage of streaming is first and foremost that it is convenient enough. Because whether it is AppleMusic, Sony Select, Tidal, Qobuz, or domestic NetEase Cloud, QQ Music, Kugou and other major streaming media platforms, all support the wireless push function, and it is much easier to find songs online than to download and collect them one by one.
Among these software, AppleMusic has the richest music library and the most comfortable experience. It is all-encompassing, including copyrighted music from almost every country and all genres. Its localization is also stronger than other foreign music apps. The monthly membership fee is only 10 yuan, which will not take individual copyrights to you and does not limit the definition, which is simply too cost-effective. All you need is an iphone or ipad, connect to a set of local area networks with ASURA, and click the push button in the app to enjoy high-definition music freely. It's easy and convenient to use, just like playing with mobile phones and tablets, but the sound ceiling has been raised a lot.
However, the AirPlay2 push protocol supports up to 16bit 44.1KHz audio format, which is worse than other streaming protocols in terms of clarity and dynamic range. In contrast, music platforms such as Tidal and Qobuz are compatible with the lossless DLNA streaming protocol, and can also be integrated into Roon for unified management, with the help of Roon management software, the private bridge core separation transmission protocol can achieve high-quality streaming transmission. There are enough domestic users of Roon software to facilitate someone to take it. The interface settings are also done once and can be used for life. Members can also purchase on a monthly basis through Taobao. However, what they have in common is that localization is not very good, and when looking for Chinese songs, you need to convert them to English song title search, or search by singer. After adding to the collection, you can save the trouble caused by the language barrier.
If you want to say that the music platform with the best localization has to be our NetEase Cloud and QQ Music. The familiar operation interface, all kinds of song lists recommended by netizens, and the popular variety shows, film and television, and game songs are simply all-inclusive. Private radio stations are also more down-to-earth than those abroad. However, NetEase Cloud Push Streaming is not very compatible with individual webcasts, but the QQ Music experience that applies Qplay's own push protocol is much better. But the membership price of QQ Music is not so good compared to AppleMusic, and you need to add money if you want to pursue the most high-definition format. The quality of the audio source for the 40 yuan monthly subscription has indeed improved, but it is up to you whether it is worth the price.
The reason why it takes so much space to introduce the personal experience of major streaming media apps is that the sound coming out of the network port is generally much better than that of the USB port. Even though USB and the network do not contain clock signals when sending data, the network protocol packages the data first, and then uploads and sends it out in a package. If there is packet loss, it will be reissued until the receiving end has all the data. This is not the case with the U port, where the data will be disturbed or the information will be lost due to timing delay, and it will not be retrieved when it is transmitted to the receiver. In addition, the U-port comes with a maximum output power supply of 5V1A, which causes the electromagnetic field generated in the cable to often have an impact on the signal in the data cable. What's more, the data from the USB port must first be called by the system, and it will only be transmitted to the outside after turning around on the memory, CPU, and motherboard, and the inside of the computer chassis has extremely strong electromagnetic radiation. In the process of processing the source file, the computer system also resamples the source (SRC), further losing the amount of information inherent in it. On the other hand, on the webcast side, the data stream can be pushed directly from the download URL or the local cloud disk to the network port of the network player through the system operation interface. As a result, the interference at the software and hardware levels of the system is greatly reduced. In addition to wireless streaming, with the help of reinforced overshielded network cables and low-power switches, low-loss data transmission can also be realized. Thinking about it this way, it is not surprising that the sound of the network port is superior to that of the USB port. Therefore, in the past two years, various network decoders have gradually emerged, not to mention that network streaming is convenient and easy to use, and the sound ceiling of the local network port is also higher.
Perhaps it has been tuned in a targeted manner, and the ASURA's network port and USB input side present two very different sound styles. The first impression I got from the USB side was the pitch-black background, silent and bottomless. If the way the sound background is presented on a general machine is the order of human voice-main melody-variation-overtone-background, the background wall is behind all the elements related to the song, and the reflected echo brings people spatial perception. ASURA fills every part of the music with this sense of space, and there is a clear sense of spatial separation between vocals and instruments, instruments and instruments, melodies and backgrounds. The lines at the edges of the sound knots are also obvious, so obvious that they don't look like they are stacked on top of each other, but are scattered all over the stage. The outer side of the edge of the knot is full of quiet space, and the overtones do not naturally diverge outward, but gradually decay and then retract as if encountering damping. This feeling is especially pronounced in the low frequencies, where the drum surface sounds much tighter. A normal drum beat exhibits a sense of dispersion from point to surface, with energy flowing naturally from the center to the periphery, and the pitch slowly rising as the intensity decreases. ARISA'S DRUM BEAT WAS SHORT AND FAST, THE SOUND SEEMED TO BE ARTIFICIALLY ACCELERATED, AND THE ENERGY WAS RELEASED AND QUICKLY RETRACTED. Or rather, it's a bit like a new drum that hasn't been fully cooked. On the other hand, the dynamics of the bass have been strengthened by the rapid tightening of the timbre, and listening to electronic music and rock is more emotional. There is also a problem with the strings and percussion instruments in the mid-frequency part, but it is not as obvious as in the low frequencies, and it is not audible in at least one ear, so it must be compared repeatedly. The resolution of the high-frequency band is still online, so it is not stimulated by the sense of constricted lines.
Although there is really no impurities in the background, there is no trace of restlessness, and the spatial positioning of the sound image is even more stable, but after the sense of lines is clear, I always feel that there is still a lack of musicality and atmosphere, and there is a faint digital flavor in it. This kind of listening sense may be better than the general decoding headphone amplifier in the face of some scum recordings, or noisy rock music, and even its fellow brother DA11. Because the background is clean, the edges of the knot are clear, and the sense of layering is a plus for this kind of song. But if you listen to some high-quality sound sources, then its sound is a little more vivid and natural, and there are still more traces of artificial carving. So my suggestion is that the USB filter is better not to use, the sound floor of the AUSRA U port is clean enough, and the sound image is solid and stable enough, and the double filter will make the sound lose its original taste.
On the other hand, if you change to the AUSRA network port input, the timbre of the instrumental music and vocals will also become looser. It is as if the drum surface has been "boiled open", and when it rebounds after the hammer falls, it no longer looks like the drum surface is tightened by external force, but there is a rebound action, which is a little less rigid and more soft. It is this softness and stretch that becomes the finishing touch, eliminating the faint digital flavor and adding enough sense of presence and appeal to the music. The lines at the edge of the original knot are still clearly recognizable, and the overtones have begun to extend outward from being close to the syllables, and the overtones will become more and more delicate and complete with the change of the push medium. From AirPlay with SRC, to wireless lossless DLNA, to Roon push in the network cable scenario, every step forward will bring considerable improvement in overtone texture and spatial reverberation details. In any case, when this extra sustain fills the space, the sound background no longer seems empty, the music begins to become flesh and blood, and the ratio between sound and background begins to harmonize.
Even more unusually, ASURA deliberately heightens the density of each syllable as it transitions from vowel to overtone, and the tonal details are highlighted here. Taste it carefully, this small piece of timbre is still quite interesting. It happens to be somewhere between the main note and the sustain, which not only retains the original timbre, but also has some stance that is about to radiate outward, and then gradually shifts the pitch higher, which is an extremely varied process that is easy to capture by the audience. If you give it enough density, it will add a touch of sweetness to the tone. This kind of sweetness is different from the dyeing derived from deliberately raising the overtone tone, which is an artificial change that will only make a certain frequency band, that is, a specific vocal and instrument, better, and if you change to another instrument whose main frequency band is not in this place, it will sound a little wrong. This is not the case with ASURA's tuning, which is originally part of the tone and does not affect each other, so there is no excessive sense of disobedience. It is equivalent to a sweet aftertaste without sugar, and it has a unique flavor.
This unique tuning is not limited to the subject matter and regardless of preference. It can not only inject a playful soul into the pop vocals, but also dye a layer of bright luster to the classical strings, and make those rock singers a little more infectious. Because AK4499EX has a very high decoding ceiling, it will become more detailed and realistic as the quality of the input sound source improves. Coincidentally, the webcast gives it plenty of room to play, and even after using HQPlay as the source to further upscal, the overall density of the music will be raised to another level. At this point, this sweet "taste" will become more and more intense, so that it will become the biggest highlight of ASURA's sound.
After in-depth study of the technical materials of ASURA, I feel that the difference between the two sound interfaces comes from the different audio protocols and the differences caused by the processing links. Although the USB port of this machine uses a USB architecture specially designed for audio transmission, it reduces interference by reducing pins, and uses audio protocols to avoid secondary loss during transcoding. However, USB transmission itself has its own loss, and then it is filtered and shaped by the FPGA chip, like going through a sieve. Although the sound is clean, there is a little bit of something filtered out, so the timbre is a little tighter and thinner. And on the side of the network port, Yulong also uses other technologies that are not available in digital broadcasting. In general, unoptimized webcasts should be equipped with clock information at the same time that the CPU unpacks the network data. However, due to the limited clock performance of the CPU, the sound broadcast on the network does not show a huge improvement compared to other media. After unpacking all the data, ASURA sends the data to the local high-precision clock, aligns the clock, and then decodes it. The clock accuracy of the audio source is naturally much higher than that of ordinary webcasts, at least reaching the same level as the USB port. In addition, the interference of the webcast source data is relatively small, and the amount of internal information is more abundant, so it will sound much more substantial than the USB port.
Since the sound source part has been guaranteed by high quality, Yulong ASURA with some headphones with high resolution and good transient response will naturally dig out a high upper limit, so tablet headphones have become a good choice. Among the all-in-one machines I've heard, there aren't many that can completely push the tablet headphones. Most of the mid-frequencies are upper-eyed, the timbre is rich and complete, the spatial positioning is clear and clear, and the sound field also presents an atmospheric and spacious state. But every time I go to the low frequency, especially the moment when the energy bursts out when diving, it always gives people a feeling of powerlessness. And that's where ASURA's strength lies, as even the popular giant diaphragm flat headphones are capable of delivering surging low-frequency dynamics. It's like a drum cuff carrying air and rushing straight to your ears. This is a feeling that can only be heard on dynamic headphones and speakers, thanks to the headphone amp module inherited from Yulong's flagship DA1, so that the tablet headphones also have a similar listening experience. Although it is still a little looser than the dynamic coil, the timbre of the tablet headphones is richer and more stretched, making the texture clearer, and the restored drum sound has a unique flavor compared with the scene. Coupled with a little bit of Yulong's special sweet aftertaste, after listening to it for so many days, I already can't put down the combination of ASURA and tablet.
At that time, DA1 was also a tablet dynamic double repair, and it was also a reserved program to promote the circle headphones here at ASURA. This is especially true for the open-frame model, which is naturally large in sound field and responsive. That's right, Sennheiser's HD800/HD800s have become the benchmark again. But the 800s with the ASURA are relatively pleasing to the ear. Because the sound stage of the HD800 is a bit large, the middle of the stage seems a little empty. Under the webcast system, the overtones of the HD800S are also becoming more and more like tablet headphones. But it still maintains its own agile response. It's not in vain that I tossed a whole set of HiFi webcasting system. However, compared with the cost of digital broadcasting of big brands, I still think that the cost of DIY network cores and switches is low enough and full of fun.
Webcasting is still a relatively old and niche way to play. The threshold to get started is not low, and if you want to play well, you have to study the things inside. Such a high threshold also makes various webcasters focus on improving the user experience, but there are not many people who are serious about making sound, and the price is not so close to the people. Yulong ASURA gave another idea, it has the sound quality on par with its own flagship, and the price is relatively down-to-earth. You only need to play with your heart and find one or two seniors to give you some guidance, and you can achieve a high-quality user experience with the help of ready-made software and hardware peripheral platforms in the outside world. Compared with the same type of webcast, which emphasizes the convenience of "network broadcasting", Yulong ASURA prefers a high-quality network decoding all-in-one machine, which organically combines webcasting, digital broadcasting, and decoding headphone amplifiers, and interprets the new form of webcasting with high-level sound.