A few years ago, Apple was the first to release Airpods earbuds with “spatial audio” technology. Today, the new mobile operating system Android 13 also supports this technology from the bottom layer. In the next few years, new Android phones will gradually support this new audio technology.

The long-sleeping audio technology field

We have mentioned more than once that among the technical categories related to audio and video, audio technology is a technology category that started relatively early, and matured earlier than video and display technologies. This also means that the development path of audio technology is becoming more and more flat, especially in recent years, there have been few breakthrough and revolutionary new technologies.

“Spatial audio” technology is a relatively new, breakthrough and imaginative new technology that has emerged in the field of audio technology in recent years. However, what exactly does this technology bring to us HIFI enthusiasts? Don’t worry, let’s start with the original HIFI field.

Headphones and earbuds are taking over the mainstream audio market

If the word HIFI was mentioned 20 years ago, most people would think of large speaker products, not portable earphones or earbuds. The term HIFI has always been endowed with special qualities such as high-end and foreign style. Therefore, not everyone will be interested in exploring the “true face” of the HIFI field. These people are often dissuaded by the high price of HIFI equipment and the complicated assembly process.

With the popularity of mobile smart phones, this phenomenon has been broken before. Nowadays, if you mention the word HIFI again, most young people will first think of portable devices related to headphones.

The popularity of earphone and earbud product lines gave birth to the birth of “spatial audio” technology

Today’s consumer products are all about “profit”. To put it simply, manufacturers do what they do to make money. Smartphones have ignited the headset market, and the popularity of the headset market has led mobile phone manufacturers to further develop the “exclusive” audio technology for headsets. There is no doubt that “spatial audio” technology is a product of such an era.

The birth of a new technology such as “spatial audio” has brought a new vitality to the HIFI world. So, let’s take a closer look at what is behind this new technology?

Is “spatial audio” really a “new” technology?

In terms of the new experience brought by technology, “spatial audio” is undoubtedly a revolutionary new technology. However, if you look at it from a technical point of view, “spatial audio” is not a completely new technology.

The essence of “spatial audio” technology is still “digital audio filter”. We once had an article detailing digital audio filters, detailing the technology of “audio filters” in the vernacular. However, “spatial audio” technology is different from traditional audio filters, which are often “static”, while “spatial audio” can be regarded as a real-time “dynamic” audio filter.

Traditional audio filters process the digital audio stream with a fixed algorithm when the sound starts to play, so that the sound can be displayed with a fixed effect. For example, if you want to change the original pop music to be heard in a large cathedral, traditional audio filters will add an “echo” effect to the audio stream, so that the actual playback effect will sound like it is in a cathedral. Such changes are static and require only a single algorithm to implement.

The “spatial audio” technology is a “dynamic” audio filter. We can simply understand that, of course, when you use earbuds with “spatial audio” technology, the operating system of the mobile phone will constantly change different audio filters according to the shaking and rotation of the user’s head, so as to change the audio playback in real time purpose of the effect.

The overall implementation idea of “spatial audio” technology can be simplified as adding sensor devices such as gyroscopes to the earbuds, allowing the earbuds to transmit the movement trajectory of the user’s head to the mobile phone in real time, and the mobile phone then changes the audio filter in real time according to the movement trajectory of the user’s head The original audio data stream is processed by the algorithm, and finally the processed audio data is transmitted to the earbuds through wireless encoding. The subsequent technical processing flow is the same as that of ordinary earbuds.

Practical uses of “spatial audio”

We can now answer the question that was buried earlier. What exactly does “spatial audio” technology bring to me?

Relieve the pressure caused by wearing earbuds for a long time

HIFI enthusiasts must be very familiar with it. The biggest difference between portable devices such as headphones and earbuds and large speakers is the “oppression”. After the sound of the large speaker passes through the reverberation of the room, the sense of hearing is very loose, and there is basically no sense of oppression when the volume is appropriate. Headphone equipment is different. Since the sound unit is very close to the cochlea, there is no room for buffering in the sense of hearing, and the sound directly enters the human ear. It has a certain “oppressive” sense of hearing when worn for a long time.

In fact, throughout the history of audio technology, there have been various technologies to help reduce the sense of oppression for headphone users. Among them, the actual effect of “spatial audio” technology should be among the best.

Simulate the sound effect of speakers

With “spatial audio” technology, users can have the illusion of listening to “speakers” in a certain space. We can think of this effect as a telepresence technique. But let’s not over-mythologize this technology. There is still a big gap between this sense of presence and the real speaker effect. However, earbud products must have “spatial audio” technology to achieve a breakthrough from 0 to 1, which is much better than nothing.

Prospects for the development of “spatial audio” technology

At present, the author still has some concerns about the development of “spatial audio” technology. The birth of “spatial audio” technology relies on the development of smartphone technology, and most of the earbuds that support “spatial audio” technology are accessories for smartphones. Each mobile phone manufacturer uses its own algorithm and technology, and products from different manufacturers are not compatible with each other.

This is undoubtedly an obstacle to the development of “spatial audio” technology. Android 13 has added support for spatial audio from the bottom layer of the operating system. To a certain extent, it has formulated a series of standards for “spatial audio” technology, but it only unifies the technical standards for mobile phones in the Android camp. As for the future, it is still unknown whether the major mobile phone manufacturers will dance with demons.

“Spatial audio” technology is still in its infancy. There are few types of earbuds supported, and the actual use effects of the few supported earbuds are also different. In the past few years, it has basically belonged to the exclusive technology of Apple’s equipment. Users of non-Apple devices have basically never experienced this technology. This time, with the addition of this technology to Android 13, the audience for this technology will be further popularized to a certain extent in the future. However, it is still unknown whether this technology will become a highlight in the history of HIFI technology development. Or, it is just one of the victims of making quick money in the capital market.