What is Dolby® Headphone?

Dolby Headphone is not a headset, but a signal processing system, which is usually installed in a sound playback system, such as a sound device, or an aircraft sound system. With Dolby Headphone technology, stereo headphones are able to produce realistic sound effects that mimic a five-speaker playback system. We know that the non-standard surround sound system is based on two-channel stereo, without adding channels and speakers, and processing the sound field signal through a circuit to broadcast it, so that the listener feels that the sound comes from multiple directions and generates a simulated stereo field Dolby headphones are a type of non-standard surround sound technology.

Dolby headphones

Dolby Headphone is not a headset, but a signal processing system, which is usually installed in a sound playback system, such as a sound device, or an aircraft sound system. With Dolby Headphone technology, stereo headphones are able to produce realistic sound effects that mimic a five-speaker playback system. We know that the non-standard surround sound system is based on two-channel stereo, without adding channels and speakers, and processing the sound field signal through a circuit to broadcast it, so that the listener feels that the sound comes from multiple directions and generates a simulated stereo field. Dolby headphones are a type of non-standard surround sound technology.

Chinese name

Dolby headphones

Foreign name

Dolby Headphone

Application

Signal processing system

R & D company

Lake

Development time

1997

sound effect

Dolby Headphone.

1. Can accurately simulate the effect produced by a 5.1-channel surround sound speaker system through a pair of ordinary headphones.

2. Can bring vividness to music, movies and games

5.1-channel surround sound can be achieved with any ordinary pair of headphones.

Capable of processing 24bit / 96KHz

You can enjoy surround sound alone without disturbing others.

Improve hearing comfort and reduce "hearing fatigue".

Make stereo content sound like

Dolby headphones can have 3 different playback modes to simulate the acoustic characteristics of the corresponding real room:

DH1: This is a small, well-reverberated room, suitable for both movie and music playback. It is the "reference room" for Dolby headphones and is available on all products with Dolby headphones.

DH2: This is a more "living" (or more reverberant) room, especially suitable for listening to music.

DH3: This is a larger room, more like a concert hall or movie theater.

DH2 and DH3 are optional and may not be provided by some Dolby headset products.

Compared with ordinary headphones, Dolby headphones are less tiring and are especially suitable for nighttime and travel. Dolby Headphone technology can be combined with any type of headset, which means that we can use our existing headsets without having to re-purchase specialized headsets. Of course, just like speakers, the better the headphones, the better the sound quality.

When you enjoy a show through a stereo or home theater system, what you hear in your ears is both the sound directly from each speaker and the multiple sound reflections caused by the surfaces of the objects and furniture in the room. The sound from each speaker has acquired unique sound information before it reaches your ears. The sound information reflects the size and acoustic characteristics of the room, the location of the speakers, and the spatial properties of the original sounds to the brain.

With powerful digital signal processing technology, Dolby Headphone technology assigns two sound marks to stereo programs on each soundtrack and up to five sound marks to surround sound programs, each sound mark corresponding to a carefully arranged Corresponding speakers positioned correctly in the acoustic environment. In other words, Dolby Headphone technology can produce up to five virtual speakers in a virtual room. Subwoofer signals (".1" low-frequency effect channels in 5.1 channels) are evenly mixed into the left and right channels.

This processing technology integrates all this information in two coded channels and transmits them to each of your ears through traditional stereo headphones. In this way, the feeling of listening will be much more natural, and you will feel that the sound comes from the outside.

The working principle of Dolby headphone technology is to create an illusion of hearing: it makes you feel like you are listening to a home theater system with five speakers, but in fact you are using a pair of ordinary stereo headphones.

This illusion is based on some basic acoustic understanding: how do we judge which direction the sound comes from, how far away it is, and whether it is in motion. We can even locate and track multiple sounds simultaneously.

We can do this because sounds from a specific source reach slightly different characteristics when they reach the left and right ears. Our brains can know everything we need about the sound with just those subtle differences. Our vision is the same principle. The brain draws three-dimensional images from the visual differences between the two eyes.

As the understanding of the human auditory system deepened, in the late 1960s and early 1970s some audio research experts began to imagine that one day electronic signal processing technology could fool the brain and make the brain feel that sound came from a specific distance Direction, but in fact it's just because of wearing headphones.

But practice has shown that creating a realistic sense of distance and location in the brain is far more difficult than these early researchers had expected.

Studies on human hearing have shown that our heads and shoulders "stick" sounds from specific directions with specific marks. For example, the sound from the left reaches the right ear slightly later than the left ear, and the sound intensity is slightly lower. At the same time, the sound blocking effect of the head will also produce a filtering effect.

Researchers have discovered that this subtle difference in time, intensity, and frequency response is scientifically called "head-related transfer function (HRTF)," and the brain can discern sound sources and sound movement based on this information alone. With the use of microphones and advanced instruments, researchers can measure various types of HRTF data very accurately, and they began to imagine how signal processing systems can electronically reproduce HRTF information.

After measuring the HRTF data of a large number of subjects, it was found that these data vary greatly due to the distance between each person's ears, and the auricle and head shape of each person. Therefore, when using signal processing software to copy specific HRTF information on a computer, it seems that only a listener with the specific HRTF data can feel that the sound is coming from the right direction. The directions felt by other listeners are different, and they vary greatly.

This discovery shattered the hopes of researchers who had originally envisaged a practical 3D listening system based on headphones. This system has the same good effect for everyone, and can be integrated into a variety of consumer products. But by the early 1990s, Lake Technology Ltd. in Australia had made a series of discoveries in signal processing and psychoacoustics, which seemed to make these researchers' dreams come true.

In 1996, Lake decided to work hard to promote its unique and now patented signal processing system. Digital multi-channel surround sound technology was a powerful enabler. This technology was originally developed for movie theaters and was later introduced into home theaters by Laserdisc and the emerging DVD format.

In 1997, Lake Personal Surround was born, which is the basis of what is now called Dolby Headphone technology. Lake began contacting Dolby Laboratories, hoping that there was a potential channel to provide their technology to Dolby's certified vendors. Dolby Laboratories is impressed with Lake s achievements, agrees to help Lake further refine this technology, and recommends this technology to the production of numerous consumer electronics and PCs under the umbrella of the Dolby Certification Program Business.

The result is Dolby Headphone technology, which is a low-cost signal processing system that can realistically simulate a surround sound system with five speakers through any pair of ordinary headphones.

Dolby headphone technology has several advantages over earlier attempts at headphone surround sound technology.

First, Dolby headphone technology can clearly and clearly simulate sound from speakers located outside the listener's head. The traditional earphone listening method makes the listener feel that the sound image is generated from the head. This is because there is no sound information to simulate the sound made by the speakers in the room. But Dolby headphone technology can simulate complex acoustic characteristics in the listening room, including the reflection of sound on various surfaces, effectively tricking listeners into making them feel that sound is coming from multiple speakers around them . In addition, the technology can simulate a wide variety of rooms with different acoustic characteristics.

Second, Dolby Headphone technology is universally applicable to all listeners. Because of the major breakthroughs in signal processing technology, the system does not require conventional HRTF settings to handle differences between individuals, making the implementation and operation of the technology simple.

The third advantage is its relative simplicity, which allows Dolby headphone technology to be integrated into a variety of consumer products while still being superior in quality. It can be implemented by various digital signal processing (DSP) chips. As long as headphones can be used, Dolby headphone technology can be implemented, so the application potential of this technology is huge.

The fourth advantage of Dolby headphone technology is that although it has the advantages of a highly detailed finite-impulse response (FIR), it has almost no delay. This ensures that the audio and video programs (stereo or multichannel) can be synchronized in sound and image.

The last advantage is that no special headphones are needed. Whether it's the cheap headphones provided by the airline or the high-end

Dolby headphone technology can be embedded in digital signal processing (DSP) chips, or it can be used in software for home theater systems, digital TVs, personal computers, and portable devices. Portable devices typically only use headphones. The cost of a special application-specific integrated circuit (ASIC) design is lower than that of a typical DSP solution, but the performance is not inferior. This way you can enjoy high-quality cinema-style surround sound anytime, anywhere, without disturbing your family and neighbors.

Dolby headphone technology can also encode program content for use in certain environments where only a playback option is available. The first environment to take advantage of this technical feature was entertainment in flight: several international airlines now offer customers a Dolby headset surround experience while watching movies without adding any equipment to the aircraft. This is achieved through special flying movies, which feature audio tracks encoded with Dolby Headphone technology.

Designed from the beginning, Dolby Headphone Technology embraces all possible audio formats. traditional

1. What is Dolby Headphone Technology?

Dolby headphone technology allows you to enjoy the sound produced by a surround sound system composed of 5 speakers through any pair of ordinary headphones. It can accurately reproduce the surround sound listening experience produced by a properly positioned and adjusted 5.1-channel speaker system, ideal for portable personal surround sound enjoyment.

Dolby headphone technology is able to transmit the complete sound signal, from the sound source to the final sound signal attenuation, and every sound reflection in the process. It uses very advanced room modeling technology to make the sound field accurately reproduced, so that what you hear is the surround sound effect expected by the producer.

Dolby headphone technology can also simulate a stereo system consisting of two speakers, which can be used in personal computers, portable DVD players, A / V receivers, digital TVs and wireless headphones.

In addition, Dolby headphones eliminate the common "hearing fatigue" phenomenon of earphone appreciation, and replace it with a wide and natural sound field, so that you won't feel tired even after listening for several hours.

2. Do I need special headphones to enjoy Dolby headphones?

No need. Dolby headphone technology can get good results with any type of headphones, from cheap headphones provided by airlines to high-end electrostatic headphones. Of course, the better the headphones, the better the overall sound.

3. Can Dolby Headphone technology reproduce the ".1" signal in 5.1-channel programs?

can. In the process of restoring 5.1-channel programs, the low-frequency sound effects of the ".1" channel will be mixed into the left and right channels, and then processed by Dolby headphone technology to bring you 5.1 surround sound experience.

4. Does Dolby Headphone Technology require special adjustments to the audio system?

no. Dolby headphone technology can achieve good results without personal debugging or fine-tuning. All you need is a sound system that supports Dolby headphone technology.

5. Does Dolby Headphone Technology work with DVD-Audio?

Yes. Dolby headphone technology is suitable for 24bit / 96Khz MLP LosslessTM encoded DVD-Audio records. The most exciting feature of a DVD-Audio record is that its sound quality is exactly the same as the studio master. This way you can enjoy the best sound programs anytime, anywhere-whether you are watching a show with a portable DVD player, watching digital TV at home, or using any device that supports headphones. This technology can also be used in wireless headset products.

6. What types of products can use Dolby Headphone technology?

Dolby headphone technology can be used in almost any device with headphone output, such as portable DVD players, PCs, digital TVs, wireless products, and any other device that can handle stereo or multichannel audio with headphone output.

7. Why are there two different Dolby Headphone technology logos: one labeled Dolby Digital and the other labeled Dolby Pro Logic II?

Dolby headphone technology is designed to handle 5.1-channel signals. It can also process stereo signals; however, the stereo signals must first be converted to 5.1-channel signals. Headphone products may carry one of these two marks, depending on the manufacturer.

Products bearing the Dolby Pro Logic II / Dolby Headphone logo can expand stereo programs into 5.1-channel surround sound, which is then processed by Dolby Headphone technology. In this way, listeners can experience 5.1-channel surround sound from stereo sources through any pair of ordinary stereo headphones.

Products bearing the Dolby Digital / Dolby Headphone logo can decode 5.1-channel Dolby digital audio tracks and use Dolby Headphone technology to handle multi-channel. Because the audio tracks have been encoded with Dolby Digital 5.1, each channel is independent. Dolby headphone technology allows listeners to get a Dolby Digital 5.1 surround sound experience with any ordinary pair of headphones.

8. Will the combination of Dolby Headphone technology and audio processing technology produce a surround effect?

can. This is the case in multi-channel speaker systems. The combination of Dolby headphone technology and sound processing technology can create surround effects for stereo material.

For example, the five- and seven-channel matrix decoders using Dolby Pro Logic II and Dolby Pro Logic IIx can make many traditional stereo programs produce a wider and more enveloping sound field. Dolby headphone technology (in multi-channel mode) can make the expanded sound field very effective, making it sound rich and natural.

9. What are the files encoded with Dolby Headphone technology in the new DualDisc?

These new discs combine traditional DVD and CD formats with HE AAC files encoded with Dolby Headphone technology. You can download these files to your MP3 player and enjoy the sound quality of Dolby Headphone technology in devices that do not have Dolby Headphone technology.