Generally speaking, there are two types of sound effect functions on MP3 players:
The first type is for the audio signal during the conversion, transmission, amplification, and playback process, due to the sound source and The distortion caused by equipment factors can be reasonably and effectively corrected and compensated, so that the listening effect is closer to the desired effect of the music work itself (that is, the "original taste" we finally understood above). Dolby noise reduction and BBE are the best representatives of this type of sound effects. We can call it restorative sound.
The second type is to perform spatial surround, sound field broadening, dynamic enhancement and other processing on the basis of the original music to make the listening effect more colorful. SRS is a typical representative of this type of sound effect. We can call it decorative sound effects.
From a technical perspective, the properties of these two types of sound effects are completely different. The work done by restorative sound effects is a kind of work that improves the quality of music, restores music details, improves music clarity, and plays an important role in reproducing the "original taste" of music. It is very necessary work. Modifying sound effects are based on existing music, and have the effect of decorating and modifying the music, making the music more pleasing to people's ears and more suitable for their own listening sense.
The sound effect technology used in MP3 players mainly includes B&O Ice Power, which is known as the "King of Sound Effects". Samsung DNSe sound effect technology, SRS (WOW) 2.0 3D surround sound technology, LifeVibes sound effect launched by PHILIPS, iriver Xtreme3D sound effect technology, etc. Let's discuss the technical principles, sound effect processing characteristics and specific performance of these sound effects. BBE High Definition Sound System is patented by BBEsound, Inc. in the United States. The technology originated in 1985. After several generations of development, BBE technology has developed from the patented technology originally applied to power amplifiers to From AV audio-visual, Walkman, radio, CD and now digital audio technology and other fields.
As we all know, people listen to original music in music venues. However, when the sound of the music venue is recorded and played back, the speakers will produce a frequency-related phase shift. This is due to the loudspeaker sound. The coil has an inductor and the electromagnetic induction generated by its moving parts will produce a large inductive reactance as the frequency signal increases. As a result, the high-frequency waves are delayed, and the high-order harmonic components carried in the emitted sound are delayed. Although its acoustic spectrum and The electrical signal spectrum is exactly the same, but this sound sounds like it lacks high-frequency components, is unclear, becomes vague and muddy, and the sound seems to be muffled. In order to restore its clarity and resolution, tone control is usually used A circuit or equalizer is used to enhance the high frequency part, which will sound better but always feels unnatural because this sound does not actually exist and is unreal in nature.
Original sound
Unamplified
The first part of the transient signal shown BBE shutdown - the sound copied by the audio system
Note the initial transient Lost peak distortion of state signal BBE on - sound copied by BBE processing
Distortion corrected
Phase delay corrected.
BBE technology does not simply enhance high-frequency waves, but advances the delayed high-frequency waves and places them before the fundamental wave. It also uses some enhancement techniques to restore some weakened high-frequency waves. BBE divides the audio signal into three parts: low frequency below 150Hz, medium frequency between 150 and 1200Hz, and high frequency above 1200Hz. BBE technology delays the mid-frequency and low-frequency parts by 2.5 milliseconds and 0.5 milliseconds respectively, leaving the high-frequency part unchanged. As a result, the high-frequency part is relatively advanced in time, so that the overall effect of the phase transition is very flat and linear. BBE uses medium and high frequency signals as its adaptive amplitude compensation reference. By closely monitoring the medium and high frequency signals, the absolute value circuit and its auxiliary circuit, it continuously outputs a signal that reflects the high-order harmonic output. Based on VCA control, it can intelligently automatically adjust the amplitude of high-order harmonics to the optimal state.
At the same time, BBE can also be used to restore the phase and amplitude of high-order harmonics. The BBE processor is equipped with a low-frequency amplification circuit, which can amplify low-frequency waves in the range of 50-150HZ in a very linear manner, and can be linearized as the frequency decreases. By increasing the delay, 20Hz sound waves will get a 2.5ms delay relative to higher frequency sound waves. This feature makes the bass very tight and clear, and sounds very natural.
It should be noted that the commonly referred to as BBE technology is just a general term. In fact, BBE technology has different branches for different applications, and BBE is the most basic one. Depending on the application, Also includes: BBE - the most basic algorithm, all other branches are based on BBE BBEMach3Bass - bass boost algorithm, which has a wide range of applications BBEViVA - BBE's 3D effect, suitable for stereo TVs, portable single-sound speakers, etc. BBEMP - Compression compensation algorithm, suitable for MP3, MD and other products that use lossy compressed music formats BBEOptima - Simplified BBE related algorithm, BBE algorithm without adjustment items BBEK3/K1 - Compression/limiting/automatic gain control, suitable for professionals Program recording BBET2/T2R/T 2C /T 2M -BBE telephone technology, comprehensive use of BBEMP and BBEK3 technology to achieve high-quality telephone call effects.
Since BBE Sound has always had very strict quality control on BBE technology, to put it simply, although the licensing fee for BBE technology is very low, it is not that simple to obtain BBE authorization. After the cooperative company applies to BBESound, BBESound will first send people to investigate the cooperative company. Only after the company's strength is recognized will it be authorized by BBE. During the product design process using BBE technology, BBESound will Participate in the design of the sound effects, and only after the final sound quality is approved can the product be marked with the BBESound trademark. It is this rigorous operation method that makes the BBE trademark become an identification mark symbolizing high quality in the audio industry.
In the late 1980s, Aiwa released the world's first walkman equipped with BBE sound effects, model HS-PL50/RL50. Later in the 1990s, it released a series of tape walkmen equipped with BBE sound effects. , was extremely popular at the time and became the favorite of many Walkman enthusiasts, thus creating the heyday of Aiwa. The BBE logo has also become the exclusive technology of AIWA Walkman. In 1996, Aiwa released the last Walkman equipped with BBE sound effects - HS-JX959/859. After that, the BBE system disappeared in the world of Walkman and became "unsound".
After entering the MP3 era, the BBE sound effect system, which has disappeared from the Walkman, has once again become the most eye-catching sound processing system on the Walkman under the development of IAUDIO, a Korean MP3 manufacturer. On MP3, Walkman fans once again hear the sound from the BBE sound processing system.
Currently in the field of MP3, only South Korea's IAUDIO and China's Truly have been authorized by BBESound. Currently, iAUDIO has many MP3s equipped with BBE sound effects system, while Truly's MP3 with BBE sound effects currently only has FT602. payment. Most readers are familiar with the various models of IAUDIO, so I won’t introduce them here. Interested readers can refer to (Objective and in-depth exploration of the sound quality and sound effects of three MP3 models of iAUDIO). The following introduces the BBE sound performance of Truly FT602.
The BBE sound system of FT602 is designed by BBESound company and optimized based on TELECHIPS 766 chip. In addition, the audio formats supported by this machine include mp3, WMA, WAV and OGG, especially Support for the latter two formats should theoretically provide quite excellent sound quality performance.
In the actual sound audition, we found that after BBE's restoration and modification, the sound came out really impressive, especially when the bit rate is not too high, BBE will simulate the audio signal lost due to compression and reproduction to make the final sound presented to the listener better.
When the sound sounds, you will immediately feel a sense of enlightenment. The sound field is wide and the sound bottom is mellow and full. In terms of low frequency, not only the sense of volume is sufficient, but also the layers can be felt to be clearer and the details are highlighted. Not to mention the high frequency, the roughness and hoarseness of low bit rate music are swept away, making it appear loud and smooth, and the mid-frequency vocals are also more mellow. and warmth. Due to the compensation and correction effects of BBE, the sound produced by FT602 is more gorgeous in overall effect. From the listening point of view, BBE's improvement in high frequencies and the entire sound field is the most obvious. However, this change in the sound field is obviously different from the surround effect of SRS that forcibly pulls the sound to both sides. It is more realistic and has a sense of presence. More natural.
The BBE sound effect of FT602 can only be turned on or off, but cannot be set and adjusted like some iAudio models. It seems that Truly needs to further develop and utilize the BBE sound effect. SRS (Sound Retrieval System) is the most representative 3D stereo technology developed by SRS Research Institute. The core of this technology is the ability to use 2 speakers to achieve a surround sound effect.
SRS is a non-hardware three-dimensional sound field. Based on auditory psychology, it simulates a three-dimensional sound field to make the listener feel like they are in a three-dimensional sound field. In fact, this "three-dimensional sound field" does not exist. It It is just a kind of virtuality, just like the three-dimensional movies and stereoscopic photos we have seen, which also use technical means to transform two-dimensional plane objects into three-dimensional spatial objects. SRS psychologically and subjectively restores the sound wave state (direct sound, reflected sound, reverberation sound) caused by the original sound source at both ears, and reproduces the orientation and spatial distribution of the original sound source, making people feel as if they are on the scene. Feel. Due to its simple sound source requirements and wide adaptability, all Dolby software and even mono software can be applied.
With the further development of technology, SRS Lab has recently upgraded the SRS sound effect to version 2.0. The new SRS WOW sound effect brings the simulation of the three-dimensional sound field to its fullest, bringing more brilliant sound effects to MP3 Effect.
SRS WOW, which consists of four parts: SRS, FOCUS, TruBass and Boost. SRS can recover spatial information that is obscured by traditional recording and playback equipment. There is no so-called sweet spot. Therefore, music and sound seem to fill the room, making the listener completely surrounded by full three-dimensional sound.
The new FOCUS generates a sense of height in the sound image by improving imaging. When combined with SRS 3D, FOCUS enhances the sound image, producing a very high and wide soundstage beyond the sweet spot. In addition, FOCUS can improve high-frequency transparency and immerse the listener.
TruBass is a patented SRS technology that uses patented technology of human voice psychology to enhance bass performance. This results in a deep and rich listening experience that is an octave lower than the low-frequency limits of small, medium and large speakers and headphones. Compared with SRS1.0, the effect of SRS2.0 has been significantly improved, especially in sound positioning and bass performance.
Boost can set frequency band enhancement, adjust the enhanced frequency range according to the characteristics of the paired headphones, and coordinate with FOCUS to achieve a more perfect sound field expansion effect. Simply put, the essence of SRS technology is the creation of a three-dimensional sound field. , use software and small sound field equipment (earplugs, headphones) to simulate a three-dimensional sound field to obtain a larger space atmosphere effect. TruBass will increase the strength and volume of low frequencies.
The MP3 players that currently officially support SRS2.0 sound effects include IRIVER’s T20, N11 and other models. Meizu’s X6, X2, E5, ME, MI, E2 and other models can also obtain SR2 by upgrading the firmware. .0 Sound System.
SRS WOW sound effects have always been favored by Korean MP3 brands, especially most MP3s from brands such as Samsung and MPIO are equipped with SRS WOW sound effects. In the past, Philips chips were used In the era of , IRIVER, as the leading brand of Korean MP3 players, has always used the Xtreme 3D sound effect technology developed by IRIVER and Philips. After IRIVER fully switched to Samsung's decoding chip, the built-in sound effects also changed from the previous Xtreme 3D sound effect to SRS WOW. Sound effects, and takes the lead in applying the latest version SRS 2.0 of SRS WOW sound effects. Let’s take a look at the breakthroughs in sound performance of IRIVER T20 equipped with SRS 2.0 sound effects.
T1O's SRS sound effects are divided into SRS WOW, FOCUS, TruBass, and Boost parts, and the sound effects of each part can be superimposed. After turning on the SRS WOW option, you can obviously feel that the sound field gradually widens, creating a 3D surround stereo sound effect. For some music, the sound field can be significantly improved. The adjustment range of SRS WOW is adjustable from 1 to 10. If you change this Excessive adjustment of the options will cause the sound to diverge and cause sound distortion. The defects of the SRS 1.0 version still exist in the 2.0 version.
The adjustment range of the FOCUS option has three levels: LOW, MID, and HIGH. When it is turned to the HIGH level, the sound is obviously clearer and the high-frequency transparency is also greatly improved. TruBass can significantly improve the bass effect, making the bass part more powerful and the vocal density also increased. However, if it is increased too much, it will also cause sound distortion and reduced resolution. The adjustment range of the Boost option is from 40-400. When the value changes from low to high, it feels like the human voice changes from the back of the head to the middle, and the sound field is improved. Generally speaking, after turning on the SRS sound effect, the sound field of the sound becomes wider, the three-dimensional stereoscopic feeling increases, and the low-frequency density increases. However, it also brings problems of distortion and blurred positioning. It can be seen that the sound effect, if applied properly, can be very effective. A good way to improve the listening experience of music will make it more pleasing to people's ears, but if it is not adjusted properly, it will also have a certain impact on the listening experience. LifeVibes technology is a professional-grade sound effect technology with extremely low memory usage developed by Philips. It is specially developed for digital music products. LifeVibes sound effects are top-notch professional sound effects developed by PHILIPS with 50 years of acoustic experience, specially developed for the field of portable digital music. Its characteristic is that it can not only improve the sound effect, but more importantly, solve the problem of sound quality degradation caused by high-frequency loss of compressed music. It can restore and improve the sound quality loss of various compressed music through optimization algorithms based on variable decoding technology. And it can improve the sound quality while relieving the hearing fatigue caused by using headphones. It is a professional-grade sound effect with extremely low memory usage specially developed for music digital products. It includes three sound effects: C.Sound (Concert Sound), P.Studio (Pure Studio), and P.Bass (Pure Bass), and supports sound effects/EQ overlay.
C.Sound (surround three-dimensional sound effect);
Using headphones can also enjoy perfect music playback like a large concert
Pass Speakers located closer can also experience a very spatial music playback effect
Surround three-dimensional sound technology can combine bass boost and treble enhancement
Effectively relieve listening fatigue
Includes dynamic low-frequency boost;
Includes pure bass
LifeVibes Pure Studio (high-frequency expansion restoration sound effect)
Repairs channel crosstalk that affects sound quality and Distortion part
Repair the compressed high-frequency part in all music file formats (MP3, ACC, WMA) to improve the sound quality
Improve the brightness and stereo effect of the music
LifeVibes Pure Bass
Real and outstanding sub-bass enhancement propulsion effect that does not rely on volume and psychoacoustic principles
Suitable for use on various headphones and speakers
Ultra-smooth low-frequency boost.
At present, LifeVibes sound effects should mainly be used on MP3s using Philips chips. MP3s that support LifeVibes sound effects include Meizu's E3, E3C and Gemei's T5.
Take Gemei T5 as an example to introduce the actual effect of LifeVibes sound effects. T5's LifeVibes sound effects are divided into two parts. One part is 3D sound effects. This part has subwoofer and concert hall sound effects that can be set. The corresponding ones are Pure Bass and Concert Sound (surround three-dimensional sound effects) sound effects in LifeVibes sound effects. This part The two sound effects can be superimposed. After turning on the 3D sound effect, the sound will be correspondingly distorted and muddy, and the actual listening experience is not good.
The other part is the Pure Studio (high frequency extended sound effect) sound effect. The function of the Pure Studio sound effect is to repair the channel crosstalk and distortion parts that affect the sound quality and in all music file formats (MP3, ACC, WMA) The compressed high-frequency part is used to improve the sound quality, improve the brightness and stereo effect of music. After turning on the Pure Studio sound effect, the sound quality can be significantly improved, the details are richer and more delicate, the sound is brighter, and the human voice has a closer feel. Enhanced, the Pure Studio sound effect is close to the BBE MP sound effect in iAudio's BBE sound effect. Although the Pure Studio sound effect will also bring a little distortion, compared with the improvement obtained, the distortion is completely negligible. Unfortunately, Pure Studio sound effects cannot be layered with other sound effects. As a leading brand in the MP3 field, IRIVER also has special technology in MP3 sound effects. When MP3 sound effects were not yet popular, IRIVER relied on the Xtreme 3D sound effect technology jointly developed by it and Philips. Although it is no longer in use now Philips chips have given up using Xtreme 3D sound effects on its MP3s, but Xtreme 3D sound effects have long been famous with the IRIVER iFP100, 300, 500, 700, 800, 900 and 1000 series MP3s, and are also loved by some IRIVER FANS.
The essence of Xtreme 3D sound effect is the application of virtual surround sound technology on MP3. Its implementation is to use a DSP to decode the signal from the decoding chip, and simulate the sound field through a series of functions and precise calculation processing. The simulated signal is then sent to the headphone amplifier section for amplification and output to the headphones. Xtreme 3D does not have a preset value. Users can set the dB number of different frequency bands by themselves through the 3D EQ setting. The usage method is the same as Xtreme EQ. The DBE setting can be used to adjust the BASS level and enhance the bass effect.
As far as the specific listening experience is concerned, although Xtreme 3D can be turned on to bring 3D surround sound effects, this simulated sound field will make people feel that the mid- and high-frequency parts are weak and the mid-frequency part is distorted. The important impact is that people The sound does not sound very realistic, and it feels a bit like electronic music. The waveforms of the sound are smooth, but after simulation they become sharp waveforms, so you will feel distortion in the sense of hearing. Xtreme 3D can play a very good role in rendering some concerts and live recorded JAZZ music, but for large-scale symphonies, NEW AGE is not suitable. Whether to turn on Xtreme 3D should be based on the user's own feelings and the music they are listening to. to be sure. Samsung has always been a pioneer in MP3 sound effect technology. Samsung was the first to apply sound effect technology to MP3. When it launched the YEPP 55 series, it was equipped with SRS WOW technology. With the development of technology, Samsung has gradually given up on MP3 is equipped with SRS WOW sound effects, but uses self-developed DNSe sound effect technology.
DNSe is the abbreviation of Digital Natural Sound Engine (Digital Natural Sound Engine). It adopts the 5.1 audio DSP sound technology of Samsung home theater system and combines the mp3 of portable combo speakers with DNSe. The dynamic sound effects of the function and the street mode of the "Dynamic Range Control" function, etc. DNSe technology was originally used in the 5.1 audio system of Samsung home theater system, and now it has been extended to MP3 players. With the cooperation of portable combination speakers, it will bring a more realistic sense of the scene, strengthen the accent, and eliminate the popping sound commonly seen in ordinary products.
DNSe sound effect technology was first and most applied to YP-T8. T8 provides a variety of surround effects such as 3D studio, 3D club, 3D stage, etc., as well as common normal, rock and other sound effects. The choice is very wide. In terms of richness and listening experience, the DNSe sound effect brings a more realistic sense of liveness, and the emphasis of the accent part is also very good, without the past phenomenon of almost sonic boom under certain conditions. It can be said that Samsung has achieved excellent results in the transition from SRS to DNSe. At present, DNSe sound effect technology has been increasingly used in Samsung MP3. The emergence of DNSe sound effect technology has also improved the sound quality evaluation of Samsung MP3. I believe that with Samsung’s vigorous promotion, DNSe sound effect technology It will become one of the most watched sound effects technologies.