The first category is to correct and compensate the distortion caused by factors such as sound source and equipment in the process of audio signal conversion, transmission, amplification and playback, so that the listening effect is closer to the expected effect of the music work itself (that is, the "original flavor" we finally understand above). Dolby noise reduction and BBE are the best representatives of this sound effect. We can call it restoring sound effects.
The second is based on the original music, through spatial surround, sound field widening, dynamic enhancement and other processing, so that the listening effect is more colorful. SRS is a typical example of this sound effect. We can call it decorative sound effects.
From a technical point of view, these two sound effects are completely different in nature. The work of restoring sound effects is necessary to improve music quality, restore music details and improve music clarity, and plays an important role in reproducing the "original flavor" of music. Decorative sound effect is the function of decorating and modifying music on the basis of existing music, making music more pleasing to the ear and more in line with one's own listening sense.
The sound technologies applied to MP3 players mainly include B&; The power of ice. Samsung DNSe sound technology SRS(WOW)2.0 3D surround sound technology, LifeVibes sound technology introduced by Philips, iriver Xtreme3D sound technology and so on. Let's discuss the technical principles of these sound effects, the characteristics of sound effect processing and the specific performance. Bbe HD audio system is patented by American BBEsound, Inc., and its technology originated from 1985. After several generations of development, BBE technology has developed from the patented technology originally applied to power amplifier to the fields of AV audio-visual, walkman, broadcasting, CD and now digital audio technology.
As we all know, people listen to authentic music in the music field, but when recording and playing back the sound in the music field, the speaker will produce a frequency-related phase shift, which is due to the inductance of the speaker voice coil and the electromagnetic induction generated by its moving part. With the increase of frequency signal, it will produce great inductive reactance, which will lead to the delay of high-frequency wave and the delay of higher harmonic components carried in the emitted sound, although its sound spectrum is exactly the same as that of electric signal. But this kind of sound makes people feel lack of high-frequency components, unclear, fuzzy and turbid, and the sound seems to be covered. In order to restore its clarity and resolution, tone control circuits or equalizers are usually used to enhance the high-frequency parts, which will sound better but always make people feel unnatural, because this kind of sound actually does not exist and is not true in essence.
original sound
Unamplified
The first part of the transient signal BBE is turned off-the sound reproduced by the audio system.
Pay attention to the loss of initial transient signal, peak distortion, BBE- the sound reproduced by BBE processing.
Corrected the distortion.
The phase delay is corrected.
BBE technology is not simply to enhance the high-frequency wave, but to advance the delayed high-frequency wave and put it in front of the fundamental wave. It also uses some enhancement techniques to recover some weakened high-frequency waves. BBE divides the audio signal into three parts: low frequency below 150Hz, intermediate frequency below 150- 1200Hz and high frequency above 1200Hz. BBE technology delays the intermediate frequency and low frequency parts by 2.5 milliseconds and 0.5 milliseconds respectively, and the high frequency part remains unchanged. As a result, the high frequency part is relatively advanced in time, which makes the phase transition very flat and linear in overall effect. BBE uses intermediate and high frequency signals as its adaptive amplitude compensation reference. The absolute value circuit and its auxiliary circuit continuously output a signal reflecting the output of higher harmonics by closely monitoring the middle and high frequency signals for VCA control, so the amplitude of higher harmonics can be intelligently and automatically adjusted to the best state. At the same time, the phase and amplitude of higher harmonics can be recovered by BBE. BBE processor is equipped with low-frequency amplification circuit, which can amplify low-frequency waves in the range of 50- 150 Hz in a very linear way, and can linearly increase the delay with the decrease of frequency. The sound wave of 20Hz will be delayed by 2.5ms compared with the sound wave of higher frequency, which makes the bass very compact and clear and sounds very natural.
It should be noted that the BBE technology is just a general term. In fact, BBE technology has different branches in the face of different applications, and BBE is the most basic one. According to different applications, it also includes: BBE-the most basic algorithm, and other branches are BBE Mach 3 bass lifting algorithm based on BBE. The 3D effect of BBEViVA -BBE is widely used, which is suitable for BBE EMP-compression compensation algorithms such as stereo TV and portable single tone response, and BBEOptima-simplified BBE correlation algorithms for products using lossy compressed music formats such as MP3 and MD. BBE algorithm BBE k3/k 1- compression/limitation/automatic gain control, which removes the adjustment item, is suitable for professional program recording BBET2/T2R/T 2C /T 2M -BBE telephone technology, and comprehensively uses bbem and BBEK3 technology to achieve high-quality telephone call effect.
Because BBE audio has always had very strict quality control over BBE technology, in short, although the licensing fee of BBE technology is very low, it is not that simple to get BBE's authorization. After the cooperative company applies to BBESound, BBESound will send people to investigate the cooperative company first, and then get BBE's authorization after the company's strength is recognized. In the process of product design using BBE technology, BBESound will participate in the design of sound effects. Only after the final sound quality is recognized can the product be branded with BBESound. It is also in this rigorous mode of operation that the BBE trademark has become a symbol of the superb quality of the audio industry.
In the late 1980s, Aiwa released the world's first walkman with BBE sound effect, the model of which was HS-PL50/RL50. Later, in the 1990s, Aiwa released a series of tape walkmen with BBE sound effects. At that time, the scenery was infinite and it became the favorite of many walkmen, thus creating the heyday of Aihua. BBE logo has also become the proprietary technology of AIWA Walkman. After 1996 Aihua released the last walkman with BBE sound effect-HS-JX 959/859, BBE system disappeared in the walkman industry and became a "unique sound".
After entering the MP3 era, BBE sound system, which has disappeared from the walkman, has once again become the most noticeable sound processing system in the walkman under the development of IAUDIO, a MP3 manufacturer in South Korea. On IAUDIO's MP3 player, walkman fans once again heard the sound from BBE sound processing system.
At present, in the MP3 field, only IAUDIO of South Korea and Xinli of China have been authorized by BBESound. IAUDIO currently has a variety of MP3s equipped with BBE audio system, while Xinli has only one FT602 MP3 equipped with BBE audio system. Most readers are familiar with various models of IAUDIO, so I won't introduce them here. Interested readers can refer to (objectively and deeply explore the sound quality and sound effects of three MP3 players of iAUDIO) to introduce the BBE sound performance of Sony FT602 below.
The BBESound system of FT602 was designed by BBE Sound Company and optimized based on TELECHIPS 766. In addition, the audio formats supported by this machine include mp3, WMA, WAV and OGG, especially the latter two formats, which should have excellent sound quality in theory. In the actual audition, we found that the sound restored and modified by BBE is really impressive, especially when the bit rate is not too high, BBE will simulate and reproduce the audio signal lost due to compression, so as to finally present a better sound to the listener.
As soon as the sound rings, people will feel suddenly enlightened. Sound stage is open and full of voice. The low frequency is not only full of sense of quantity, but also can feel clearer levels and details. Not to mention the high frequency, sweeping away the roughness and huskiness of low bit rate music, it looks bright and supple, and the sound of the intermediate frequency is more round and warm. Due to the compensation and correction of BBE, the overall sound effect of FT602 is more gorgeous. From the sense of hearing, BBE improves the high frequency and the whole sound field most obviously, but the change of this sound field is obviously different from the effect of SRS forcibly pulling the sound to the sides around the stereo, but it is more real and more natural.
The BBE sound effect of FT602 can only be set on or off, but it cannot be set and adjusted in many ways like some models of iAudio. It seems that Sony needs to further develop and utilize BBE sound effects. SRS (Sound Retrieval System) is the most representative 3D stereo technology developed by SRS Research Institute. The core of this technology is that surround sound can be obtained by using two speakers.
SRS is a non-hardware three-dimensional sound field. From the perspective of auditory psychology, simulating a three-dimensional sound field makes the listener feel like he is in a three-dimensional sound field. In fact, this "three-dimensional sound field" does not exist, just a virtual one, just like the three-dimensional movies and stereo photo we have seen. These are also technical means to transform two-dimensional plane objects into three-dimensional objects. Psychologically and subjectively, SRS restores the sound wave states (direct sound, reflected sound, reverberation sound) caused by the original sound source in both ears, and reproduces the orientation and spatial distribution of the original sound source, making people feel as if they were there. Because of the simple requirements for sound sources and wide adaptability, all Dolby software and even mono software can be applied.
With the further development of technology, SRS Lab recently upgraded the SRS sound effect to version 2.0. The brand-new SRS WOW sound effects bring 3D sound stage simulation to the extreme, and bring more gorgeous sound effects to MP3.
Srsworw consists of SRS, FOCUS, TruBass and Boost. SRS can recover the spatial information covered by traditional recording and playback equipment, and there is no so-called sweet zone. Therefore, music and sound seem to fill the room, so that the listener is completely surrounded by the complete three-dimensional sound.
By improving the imaging level, New Focus has produced high-quality sound images. When used in combination with SRS 3D, FOCUS will enhance the sound image and produce a very high and wide sound field beyond the best listening point. In addition, FOCUS can improve the high-frequency permeability and immerse listeners in it.
TruBass is a patented SRS technology, which uses patented vocal psychology technology to enhance bass performance. Therefore, it can present an octave lower than the low frequency limit of small, medium and large speakers and headphones, and the listening sense is profound and rich. Compared with SRS 1.0, SRS2.0 has obviously improved the effect, especially in sound localization and bass performance.
Boost can set the frequency band enhancement, adjust the enhancement frequency range according to the characteristics of headphones, and cooperate with FOCUS to achieve a more perfect sound field expansion effect. In short, the essence of SRS technology is to create a three-dimensional sound field. Use software and small sound field equipment (earplugs, headphones) to simulate a three-dimensional sound field, and obtain a greater spatial atmosphere effect. TruBass will increase the strength and sense of low frequency.
At present, there are some MP3 players that officially support SRS2.0 sound effects, such as T20 of IRIVER, N 1 1, X6, X2, E5, me, MI, E2 of Meizu, etc. You can also get the SR2.0 sound system by upgrading the firmware.
SRS WOW sound effects have always been favored by Korean MP3 brands, especially Samsung and MPIO, most of which are equipped with SRS WOW sound effects. In the past, when Philips chips were used, IRIVER, as the leading brand of MP3 in South Korea, always used Xtrem3D sound technology jointly developed by IRIVER and Philips. After IRIVER completely switched to Samsung's decoding chip, the built-in sound effect changed from the previous Xtrem3D sound effect to SRS WOW sound effect, and the latest version of SRS WOW sound effect was first applied. Let's take a look at the breakthrough of IRIVER T20 in SRS 2.0 sound effect.
The SRS sound effects of T 1O can be divided into SRS WOW, FOCUS, TruBass and Boost, and the sound effects of each part can be superimposed. After turning on the SRS WOW item, you can obviously feel that the sound field is gradually widened, creating a 3D surround sound effect. For some music, sound stage can be significantly improved. The adjustment range of SRS WOW can be adjusted from 1 to 10. If this option is adjusted too much, the sound will be divergent and distorted, and the defect of SRS 1.0 still exists in version 2.0.
The adjustment range of focus options has three levels: low, medium and high. When the focus option is turned to high level, it is obvious that the sound is clearer and the high-frequency permeability is greatly improved. TruBass can obviously improve the bass effect, make the bass part stronger and increase the vocal density, but if it is increased too much, it will also bring about the distortion of sound and the decline of analytical power. Boost options can be adjusted in the range of 40-400. When the value changes from low to high, people feel that the sound changes from the back of the head to the middle, and the sound level is improved. Generally speaking, after the SRS sound effect is turned on, the sound range is widened, the stereoscopic effect is enhanced, and the low-frequency density is increased, but at the same time, it also brings the problems of distortion and fuzzy positioning. It can be seen that for sound effects, if properly used, it can improve the listening sense of music and make it more pleasing to the ear, but if improperly adjusted, it will also make the listening sense certain. LifeVibes technology is a professional sound technology developed by Philips, which is specially developed for digital music products with extremely low memory occupation. LifeVibes sound effect is a sword honed by Philips' 50-year acoustic experience, and it is the top professional sound effect specially developed for portable digital music. Its characteristic is that it can not only improve the sound effect, but more importantly, it solves the problem of sound quality degradation caused by high frequency loss of compressed music. Based on variable decoding technology, the loss of sound quality of various compressed music can be recovered and improved through optimization algorithm. And it can improve the sound quality and alleviate the hearing fatigue caused by using headphones. It is a professional sound effect specially developed for music digital products with extremely low memory occupation. It includes three sound effects: C.Sound (concert sound), P.Studio (pure recording studio) and P.Bass (pure bass), and supports sound effect /EQ superposition.
C. sound (surround three-dimensional stereo sound effect);
You can also enjoy the perfect music playback with headphones like a large concert.
You can also feel the music playing effect with a sense of space through the close-up speakers.
Surround 3D stereo technology can combine bass propulsion and treble enhancement.
Effectively relieve hearing fatigue
Include dynamic low frequency propulsion;
Contains pure bass
LifeVibes Pure Studio (high-frequency extended restore sound effect)
Repair crosstalk and distortion that affect sound quality.
Repair the compressed high-frequency parts in all music file formats (MP3, ACC, WMA) to improve the sound quality.
Improve the brightness and stereo effect of music.
LifeVibes pure bass
Independent of the principle of volume and psychoacoustics, a truly excellent subwoofer enhances the propulsion effect.
Suitable for all kinds of headphones and speakers.
Ultra smooth low frequency propulsion.
At present, LifeBees sound effects should be mainly used for MP3 of Philips chips, and MP3 supporting LifeBees sound effects include E3 and E3 of Meizu and T5 of Meg.
Taking Meg T5 as an example, this paper introduces the actual effect of LifeVibes sound effect. T5' s Lifebebes sound effect is divided into two parts, one part is 3D sound effect, and there are bass and concert hall sound effects that can be set, corresponding to the pure bass and concert sound (surround 3D stereo) sound effects in Lifebebes sound effect, which can be superimposed. After turning on the 3D sound effect, the sound will be distorted and turbid, and the actual listening feeling is not good.
The other part is pure Studio (High Frequency Extended Sound Effect) sound effect, which is used to repair the channel crosstalk and distortion that affect the sound quality in all music file formats (MP3, ACC, WMA) and the compressed high frequency part, so as to improve the sound quality and enhance the brightness and stereo effect of music. After the sound effect of pure recording studio is turned on, the sound quality can be obviously improved, the details are richer and more delicate, the sound is brighter and the sense of human voice is enhanced. The sound effect of Pure Studio is close to that of BBE MP in iAudio's BBE sound effect. Although the sound effect of the pure recording studio will also bring a little distortion, compared with the improvement, the distortion can be completely ignored. Unfortunately, pure studio sound effects cannot be superimposed with other sound effects. As a leading brand in MP3 field, IRIVER also has special technology in MP3 sound effect. Before the popularity of MP3 sound effects, IRIVER enjoyed a good time with Xrem3D sound effects technology jointly developed with Philips, although now it has given up matching Xrem3D sound effects on its MP3 because it no longer uses Philips chips. However, Xtrem3D sound effects have long been known and loved by some IRIVER fans with the series MP3 of IRIVER iFP 100, 300, 500, 700, 800, 900 and 1000.
The essence of Xtrem3D sound effect is the application of virtual surround technology in MP3. Its realization is to decode the signal from the decoding chip with a DSP, and simulate the sound field through a series of accurate calculation and processing functions. Then, the analog signal is sent to the amplifier for amplification and output to the earphone. Xtrem3D has no default value. Users can use 3D EQ settings to set the number of dB in different frequency bands, which is the same as Xtreme EQ. The setting of DBE settings can adjust the bass level and enhance the bass effect.
As far as hearing is concerned, although Xtreme 3D can bring 3D surround sound effect, this simulated sound field will make people feel weak in the middle and high frequencies, and the middle frequencies will be partially distorted. The important influence is that human voice doesn't sound very real, and it feels a bit like electronic sound. The sound waveform is relatively smooth, and it becomes a sharp waveform after simulation, so there will be a sense of distortion in hearing. Xtrem3D can play a very good role in rendering some concerts and live recorded jazz music, but for large symphonies, NEW AGE is not suitable. Whether to turn on Xtrem3D depends on the user's own feelings and the music he listens to. Samsung has always been a pioneer in MP3 sound technology. Samsung first applied sound technology to MP3, and when it launched YEPP 55 series, it was equipped with SRS WOW technology. With the development of technology, Samsung gradually gave up matching SRS WOW sound effects to MP3 and adopted its own DNSe sound effects technology.
DNSe is the abbreviation of Digital Natural Sound Engine. It adopts the sound effect technology of 5. 1 audio DSP of Samsung Home Theater System, and integrates mp3 of portable combination sound, dynamic sound with DNSe function and street mode with "dynamic range control" function. DNSe technology was originally applied to the 5. 1 audio system of Samsung home theater system, and now it has been extended to MP3 players. With the cooperation of portable audio, it will bring a more realistic sense of the scene, strengthen the pressure and eliminate the common sonic boom of ordinary products.
DNSe sound technology was first applied to YP-T8, which provided various surround effects such as 3D studio, 3D club and 3D stage, as well as common ordinary and rock sound effects. The choice is very rich. In terms of listening sense, DNSe sound effect brings a more realistic sense of the scene, and the key points are also in place, without the phenomenon of approaching sonic boom in some cases in the past. It can be said that from SRS to DNSe, Samsung has achieved excellent results. At present, DNSe sound technology has been more and more applied to Samsung MP3, and the appearance of DNSe sound technology has also improved the evaluation of Samsung MP3 sound quality. It is believed that with the vigorous promotion of Samsung, DNSe sound technology will become one of the most striking sound technology.