[Home Theater Network HDAV.com.cn] In the past 23 years, in order to produce the highest level of high-fidelity audio equipment, huge manpower and financial resources have been invested. Therefore, unlike many friends who have a fever with a relaxed attitude, they must explore and master the true meaning behind the sound, and use it to guide their own practice. So is this meaningful to our friends who just want to play with ease?! I thought about it carefully, and it still makes sense, because even if you understand and master something, you can make us less A lot of detours, which helps to reach the realm of good sound earlier! Based on this, I want to write some of my experiences for many years for your reference.
Group delay distortion
So what are the two key factors that have the greatest impact on human hearing? My long-standing experience is: the group delay distortion of music and the distortion of energy distribution!! Why are these two factors affecting the human ear? The most sensational!? This is mainly related to the two unique characteristics of our human ear! Then the human ear has the two major listening characteristics? In simple words, there are two hidden schools in the human ear: fast It will cover up the slow, strong will cover up the weak! If you are interested, you can go to the relevant literature, here is not much to say. The advantages and disadvantages of audio production and restoration are closely related to these two points - including record production, audio source, amplifier, speaker, wire to space processing, etc. The distortion of energy distribution is familiar to everyone. It is the unbalance of the common name of the burning friends. Say that a certain system is not resistant to hearing, noisy is actually too strong treble to cover the bass. "Thinking very interesting: the diaphragm of the treble is only a little bit large and the diaphragm of the bass is relatively large, but the treble The energy is still unambiguous when the bass is covered. The sound is mixed, stuffy, and unclean is often too strong low frequency to cover high frequency energy. Therefore, people often say that the energy distribution of a good sound is pyramid-shaped, low and high, and this is correct! But Jun knows whether the pyramid shape is high, low, low, large or small, and countless species. The pyramidal energy distribution makes the human ear feel comfortable. The human ear's hearing characteristics are naturally evolved by humans for millions of years. The last one is well understood, then the former one and the human ear are “quickly masked slowlyâ€. How to understand the group delay distortion of the music corresponding to the feature, which explains the trouble!
Regarding group delay distortion, I think it might be better to explain this: we use every frequency between 20--20000hz as a warrior. These 19980 fighters are all on the same starting line and rush to the same end. Go, the ideal state is of course everyone will start together and hit the line together, then the referee "ear" of your station is online and the natural music is not closed! But this ideal situation is never possible, and the situation must be This is the case: there is a front hit line with a back hit line. Everyone has a slow and slow crossing through the end point. When this happens, we call it the group delay distortion of music! Of course, this is also a lot. This is called the time distortion and phase distortion. The group delay distortion hits our human ear's "quick masking slow" feature. That's really bad! Why? Because we can only hear the fast and faster part of the music frequency. On the topic of group delay distortion, there are too many words to say, in general, group delay distortion is the most fierce and most difficult to deal with in high fidelity replay!! Let's slowly say! Group delay distortion At present, there is no instrument that can accurately measure, but Gao Wen seems to be psoriasis saying that their test is in units of one billionth of a second, but the language is unknown. But for Gao Wen’s boss, I agree with it: the only goal of replay is to reproduce the real voice, not the artistic creation. Producing a better sound is not a very high technology, but producing a sound that reproduces real sound requires ultra-high technology.
From the above point of view, the distortion of the energy distribution and the distortion of the group delay correspond to the two characteristics of the human ear, and thus have the greatest impact on the hearing of the human ear! But the reality is more complicated, both of which In addition to affecting the sense of hearing along with many other distortions, they are also united with each other. You have me, and the mixture of you and me has increased the disadvantage of listening to the human ear. In fact, people in life experience the example of group delay distortion is the old long-distance call. When playing a very long distance, such as International Long Distance, you will find some delay in the sound time. This is because the audio signal is on the metal conductor. When transmitting, different frequencies have different conduction velocities, so the above phenomenon occurs when entering the human ear. Then these two points of distortion are so important, and there is no suitable instrument to test, then we rely on what to determine? Haha don't worry, the smart foreigners have long had a response. Let's first take a look at the answer given by a certain wire manufacturer. He said this: When the group delay is large, the following four items cannot be guaranteed when the audio is replayed: "1": the width of the sound field, " 2" The depth of the sound field, the accurate audio of "3", and the rich overtone of "4". Oh, I feel that he still misses the weight and density of a very important piece of music: When there are many bands that are masked by our ears, the energy of these lost frequencies is lost together!
The above conclusion sounds frustrating, but the fact is that! Another example: symphonicline "German Voice" boss publicly published a declaration more than a decade ago, emphasizing that he pays attention to three aspects of the correct energy allocation, 2 The correct phase, 3 touchable physical sense. Then he wrote: As a hi-end sound maker like me, I have to review the above three elements from time to time. Symphonicline has been established for 16 years and has been more than 30 years since the end of the year. The ideal goal is close to 100% "Blowing the Mavericks", which is a thank you. So far, there is no suitable test instrument in the world to measure their relationship with each other. All research must rely on the ear and nervous system... My ears and body feel are the most expensive music sounds in the world. Measuring instruments, I put this work into the work, from the manufacture of components, the selection of parts and materials to the manufacturing process. Then there were the famous concert halls built by the Europeans in the 19th century. At that time, the engineers had any test instruments, and the buildings with such excellent acoustic effects depended on their experience and ears. In the 20th century and the 21st century, the emergence of a large number of test instruments in the past century, I did not hear that the acoustic effects of the theater can be traced to the several concert halls.
Seeing this you might say: Mom's name is so simple! Just have two ears. Then these famous factories have raised prices, and all of my grandmothers have started diy and told them to drink the northwest wind! Yes, making the name is not mysterious, of course, the premise is that you have rich practical experience and several pairs of strict training. The exact ear, and an indispensable condition, is a space that is strictly acoustically processed in place. For those who don't have a good space and want to diy, for example, a friend who wants to be a speaker, it is recommended to move the equipment of the famous factory to the empty warehouse, and put it in the middle. At the same time, there is a pair of the same-caliber name speaker for reference. According to the requirements I wrote above, I can strictly and repeatedly debug, and I can make a high-quality Chinese name box! In the past, the Danish Crown was all the speakers that were debugged in a large warehouse, "no acoustic distortion of small space."
Amplifier
Let's talk about the power amplifier. Speaking of power amplifier production, it is really our strong strength. "It is also the place we think can promote the country!! Assuming that the sound industry also has the Nobel Prize, then we will be the most powerful contestants." Therefore, it is really an inexhaustible topic to talk about. There are countless efforts in the past twenty-three years. Considering the non-diy website here, it will only combine the above two factors that affect the human hearing. Let's talk briefly.
Here is a brief description of the "water pond" composed of electrolytic capacitors in the power amplifier. The "water pond" plays a crucial role in the power supply of the power amplifier because the entire power supply supplies current to the load "circuit" most of the time. The work is completely done by the discharge of the "water pond"! Therefore, most of the time, the charge and discharge rate of the "water pond" fully represents the charge and discharge rate of the entire power supply. The higher the charge and discharge rate of the power supply, the stronger the ability to follow the change of the music signal, and the more power the various transistors and integrated circuits in the circuit that are converting or amplifying the sharply changing music signal will be. Timely and more "sufficient". In this way, the less the part of the music signal that is lost when it is switched and amplified, the more complete the details of the music and the higher the fidelity of the signal! According to this theory, we will analyze each The performance of the "tank" consisting of electrolytic capacitors used in the top-level amplifiers, due to the presence of electrolytes or semiconductors such as "tantalum capacitors, os capacitors" with low conductivity inside the electrolytic capacitors, and thus high dielectric loss The internal resistance is high, so the rate of such "tank" rushing and discharging is not high, which is destined that the currents of various types of transistors and integrated circuits that are working in the amplifying circuit from the "sink" will not be too " Timely and too much!! This is actually the biggest weakness of these top-level amplifiers. The "sump" with poor performance has actually become the biggest obstacle to the further improvement of the performance of the existing top amplifiers! Here we will talk about "water" The specific situation in which the rate of the pond is not high will inevitably cause damage to the music replay: we speculate that in two aspects, "1" will cause the extremely short signal to be lost. "2" because the power supply rate of the beginning part of the signal "commonly known as the head" can not keep up, causing the letterhead to be lost or severely attenuated, and the current supply is insufficient, according to the principle of conservation of energy, the damage caused by Ken The trick is that the music signal is quite attenuated and distorted! At this time, the first thing to be attenuated or distorted is the large amount of harmonics and details with small energy amplitude. Then the energy of various fundamental frequencies in the signal will also be affected. Attenuation and distortion!
The above is only the damage caused by the poor performance of the electrolytic capacitor from the "water pump" power supply, and the performance of the other main function of the "water reservoir" is not satisfactory. "The audio signal needs to be amplified at each level inside the power amplifier. After the power supply - mainly the coupling of the "water pond" can be achieved, and the poor frequency characteristics of the electrolytic capacitor is another damage to the signal, even if it is said that the top electrolytic capacitor will be more than 4khz internal resistance will be fierce. Increase, and the capacity is also rapidly reduced as the frequency of the audio signal increases, which brings about the distortion of the energy distribution of the music signal and the group delay distortion, which brings more disadvantages to the human ear's sense of hearing... so many Years ago, a Hong Kong resident, Mr. Zhuo Yu, said in the "Fever Sound": The most perfect "water pond" in the world is a large "water pond" with many non-inductive metal film capacitors connected in parallel. This is perfect. The big "water pond" has a very fast response, extremely low internal resistance, the highest analytical power, the closest to the fidelity of the scene and the most beautiful sound quality, but unfortunately... no one... It is a pity! It is this clear understanding that we started from the first batch of more than 1,400 small-capacity ec80uf metal film capacitors at a price of 10 in 1998, and have accumulated for 12 years. Hundreds of thousands have laid a solid foundation for this ideal realization! For more than ten years, we have been working hard to make the ideals come true. Here we must pay tribute to the top engineers from abroad. They are indeed very Great!! The basic flow of the audio signal in the amplifier is this: input stage - power - main stage - power - current level - power - load "r". It can be seen that the audio signal is polluted by the power supply three times during the whole amplification process. Then why is the electrolytic capacitor and the battery of the electrolyte also have poor linearity? It is well understood that each of them is charged and discharged internally. The process is actually a chemical reaction, and the chemical reaction takes time! This is because they have low internal resistance to the low-frequency low-performance "good performance", and the high-frequency response to high rate is very difficult. The root cause of "high internal resistance" The film capacitor has no such process, so the internal resistance of the low frequency signal or the high frequency signal is extremely low, and the performance is naturally ideal. Of course, the large-capacity battery is a very pure DC power supply, so we naturally have to develop it in the top-level preamps! It is the world's best power mode with battery capacity and film capacitors.
Wire
Going back to the wire, many friends replaced the head of the silver color g6 signal line with the silver head of the wbt. After listening to it, the sound of the sound was high and unbalanced! In this case, I had to use the secret technique to balance the school. The balance sound was immediately loose, and the sound field was also wider. Of course, the details that were originally masked also appeared in large numbers. Several old people who were present agreed that they had overcome the unchanged one. This friend is ironic and wants to change his head. This is the beginning of my discovery. A few words about the mystery of the wire can be summed up, but I am worried that it is too clear that everyone will feel that the line of tens of thousands of dollars is not worth it. It is not good, so it is not good! So I have to say a few words first. The words: the price is so expensive to sell, although the principle is very simple, but the replay of music is a very complicated matter, all aspects of the factors will affect the final performance, because the high-fidelity replay of music not only has a rational aspect At the same time, there are also sensuous aspects. The development of a good product often takes several years according to the difficulty of the period. For a dozen years, for example, I am also studying the power amplifier. It is also coincidentally playing the wire because it was in 2007. I got the highest level of communication audio transmission line used by the US military 50 years ago. "The structure is exquisite, the transmission is reasonable. I don't think there is a line that can be expected. It is obvious that the best scientists at that time participated in the design because the manufacturer is The top big companies have the strength to invite high-level scientists to participate in this highly profitable but highly competitive project. In fact, just add a head. I have listened to it, but I have modified it thousands of times. After four years, I am still improving. Of course, this is related to my perfectionism. I think the best line will produce the best sound, otherwise Sorry for this expensive line of the diagnosis! The power amplifier is also the same requirement, otherwise it will not give up. It can be seen that the development of the top audio is really a difficult and difficult job!!!
All of this, to say that it goes around, but one ear hears the word of the old drawer: the skin effect. It is known that the skinning effect has a great influence on the sound reproduction, but how rarely the process is heard. The higher the frequency, the more you go to the surface of the conductor. Everyone knows that Guan Jian is in such a way that the high frequency of the surface layer and the low frequency of the inward direction and the low frequency of the center position are inconsistent. From the microscopic point of view, the impedance and the inductive reactance are different, and thus the transmission speeds of the high, medium and low frequency parts of a complete signal are inconsistent, thus generating group delay distortion. Speaking of the human ear is really a slanting door, a distance of one meter and the signal is transmitted at a speed of light, even if there is a delay, how short it is! The human ear can clearly feel it. Unbelievable. Therefore, Gao Wen will say that it is measured in units of one billionth of a second. Then, what is the transmission distance of a billionth of a second of charge in a conductor? Calculated: 300,000 km/s, which is 300 million meters/second, multiplied by one billionth of a second, equal to 0.3 meters, not enough. At least 100 times shorter - it can be accurate by measuring one billionth of a second, haha, making a joke. Then why should manufacturers do everything possible to enhance the transmission of the conductor surface? Strengthen the skin effect! Why? When the internal resistance of the conductor surface is effectively reduced, the intermediate frequency and the low-frequency signal will also come to the surface, so that Some of the signals don't all follow the same path! So they have the same impedance and inductive reactance during transmission, so the speed of transmission will be the same!
Then let's talk about the line above. We know that the midline is a well-known brand in the mid-range, and we dare to disclose our own secrets. This is admirable! Let’s see that he emphasizes self-adoption. The conductor is the perfect smooth copper "Silver", which is a relatively simple and sophisticated means, why? Because the conductor is smooth and clean, "There is a technical content", then the conductivity of the conductor surface is increased by 40% - 80%!! This makes the group delay distortion greatly reduced during signal transmission, and it is also very important that the line is also very good, that is, the air tube insulation is used, which makes the interference of the insulated object to the signal transmission greatly reduced. "Insulators have a characteristic that they are constantly doing the work of absorbing signal charge and then releasing charge. The absorption and release of different frequency bands and different amounts of insulation are different." The process is actually a process of generating group delay. : Adding certain frequency bands of the previous signal to a later signal, of course, to avoid! The use of the air tube greatly reduces the contact surface between the insulator and the conductor. So what about the more expensive high-end music, silk, silver, and silver? We see that they have adopted more complicated techniques, and they all use the method of silver-clad copper, "the transmission capacity of silver is greater than copper", and then The silver surface is polished by technical means, and the silver color and the gamma further penetrate the gold in the surface layer silver to further improve the conductivity of the conductor surface. The method of increasing the surface area by the ribbon is undoubtedly adopted. It has a good effect on further reducing the group delay distortion: when comparing the line, the sound field, the level, the image, the details and the emotions are obviously improved, which is the proof!! Therefore, it is expensive! And mit and the fairy It’s another way: they don’t pay attention to the handling of the conductors. They use the passive components such as inductors, resistors and capacitors to control and correct the group delay of the wires. “This is of course a very complicated door. Technology, it turns out that they are doing a good job! The huge sound field, rich energy and density, etc. are also proof that they have better reduced group delay distortion!
space
More than a decade ago, when bnw's nautilus was first launched, some people asked the main designer, Mr. Laurence Dickie, how big the nautilus can be in the room. The designer's answer surprised him: Nautilus is the best The performance is placed outdoors without a wall. Because there is no distortion of the indoor space, the nautilus can make a natural sound! The man then continues to ask: How much space does it have to listen indoors? Mr. Laurence thinks The answer is: the indoor performance of 12 meters wide and 9 meters long will be better! The questioner is very emotional: the low is not a businessman, so the answer is very honest - no matter how good the speaker will be subject to the user's spatial sound characteristics . Let's take a look at the words of the silver-colored boss edwin: no matter how expensive the speaker is, there is a limitation in the design. It is designed according to the ideal space conditions, so it is greatly affected by environmental factors! After the acoustic environment, the performance may be out of level. Like a Ferrari sports car, although the design and performance are excellent, it is easy to get stuck if it is on a rough road. Look at the people in the industry are outspoken, and of course we have more reason to face up to their own audition space.
When it comes to the processing of sound space, there are many disturbances in reality. There are countless theories and methods in the fashion, which is really overwhelming. Is the theory and method of spatial processing really so complicated and difficult to handle? After more than ten years of exploration and practice, Mr. Wang from my side gave an exciting and convincing answer: space processing is not secret There are completely standards to be found. As long as we firmly grasp this standard, we will surely have satisfactory results! So what is the standard of this unique standard? A: Sound field, positioning!! The space processing should be dealt with in the last ring. The important procedure before should be "1": reasonable choice and matching of equipment. "2" careful deployment of various wires and careful handling of various parts of the power supply. "3" is an effective space treatment! In terms of fever, the first two parts must be taken seriously and spent more, because they are the foundation and the cornerstone of the final high-fidelity replay. The space treatment is the last key means to ensure that the strength of the former is fully displayed and played!! So how does space affect the sense of hearing of our ears? Interested friends can take a mirror and find the speaker first. At the first counter-thank you on the six sides of the room, use a long tape measure to measure the distance from the speaker to the reflection point and then to the emperor's ear, and then compare the distance between the box and the human ear. . Anyway, I used to do it, and the data is still there. I am here to say that "the length, width and height of the space are 6.17, 4.24, 2.65 meters respectively": As for the absorption zone in the space, the diffusion is reflection, which varies from room to room and cannot be generalized.
record
And the enthusiasts all over the world don't want to present a complete, clear and realistic stage in their homes! And to truly reproduce the various instruments and vocals on the spot!! So the record companies all over the world are aiming at this goal. And in every possible way, make such a record that can satisfy the millions of fans and music lovers, otherwise he will not be able to sell it, and lose money! To record the record, it is necessary to add dozens of foreign recording industries. Over the years, there has been a set of very mature industry standards, and foreign excellent sound recording artists generally have such a recording concept when recording symphonies: not only the balanced, accurate and complete recording of the rich sounds of the various symphony orchestras, but also To fully record the atmosphere of the performance scene, that is, the rich reverberation and reverberant music characteristics of the scene, they generally like to record classical music in the concert hall instead of in the anechoic room. In the 1990s, German dg company built a 4D recording studio to record higher quality records. In fact, this studio is not what we usually call the muffler studio, but an excellent acoustic effect and full reverberation. A clear, vocal and reverberant concert hall! Great for large symphony orchestra recordings.
Therefore, some major record companies in the world of stereo recording products, such as dg, eml, Phillips, Deca, etc., they cooperate with the world's first-class symphony orchestra and well-known conductors, we have no reason and need to doubt it. The authenticity and reliability, on the contrary, using classical music, especially large symphonic works to test and adjust our audition space, through continuous efforts through the correct method, we will be able to adjust the balance, loose, natural sound space! Restoring a sound field is the starting point, basis and purpose of all household hifi space processing methods. This is indeed a remarkable creation of Teacher Wang. The concrete practice of countless times in more than ten years is also a good proof of this! My thoughts and methods have indeed captured the fundamentals of small-scale spatial acoustic processing! This has enabled us to effectively deal with the powerful reflected sound interference in a complex and seemingly unsolvable small space, so as to obtain satisfactory sound effects, we performed on the listening room. The purpose of spatial processing is to restore the balance of the reverb, overtone, and rich vocal sounds on the record. Hifi is very easy to be masked and disturbed by the defects of the listening room!! The purpose of our processing space is to remove these defects and interference, and restore the sounds and elements that should be in the record, not added!
Rationally to analyze: When we get a classical music record, do you know how much information about this record? For example, Bay 9, you certainly know that the band is that one, who is the commander, knowing where to go through the record Recording, the name of the relevant recording producer, and if you have more details, you will be given some written information such as the live photos of the recording. However, these written information did not substantially help our high fidelity replay. And the key real sound characteristics of the key at the recording site are unknown! For example, what is the reverberation time when recording? What is the hall sound? What about the reverberation? There are also various instruments in the hands of the performers. What about the original sound quality? Wait a minute...we are not at the recording site, so no one knows! More fresh and fun home theater information, please pay attention to the home theater network http:// (WeChat: Cnhifi), the nation's most influential home theater audio player interactive media site.
Note: This article is transferred from love video. The article is an independent view of the author and does not represent the position of the home theater network.
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