Wireless Hi-Fi ushers in a turning point

Wireless Hi-Fi ushers in a turning point.

“Wireless can also be called Hi-Fi?” Similar remarks were not uncommon in the HiFi circle ten years ago.

Even today, the gap between wireless and wired is still very large in the eyes of high-end Hi-Fi players. The sound quality of wireless headphones can’t catch up with wired ones.

Wireless Hi-Fi ushers in a turning point

From the hardware point of view, in addition to the audio unit, transducer and other modules necessary for traditional headphones, wireless headphones also need to insert wireless audio decoders, batteries and other modules into the cavity of the headphones.

These hardware modules will occupy the internal space of the headphones .

Due to the space, engineers had to make compromises in terms of sound quality.

In addition to its own hardware limitations, the signal transmission of wireless headphones has also been criticized.

Before wireless transmission protocols such as LDAC and LHDC matured, wireless transmission could not even meet the transmission requirements of lossless music files.

Even today, the wireless transmission protocol still has some limitations, such as small transmission distance, high delay, susceptibility to interference, etc., and even the latest wireless Bluetooth transmission protocol cannot meet the transmission requirements of DSD and other master-level audio files .

Although from personal experience, the performance of DSD and other master-level audio formats is no different from that of high-bit rate lossless audio in most cases, but in the eyes of Hi-Fi enthusiasts, perfection is the only pursuit. Before the breakthrough of Bluetooth technology。

It is impossible to complete the transfer of master-level lossless music files in a short period of time, so what method should be used to meet the needs of HiFi enthusiasts?

Some manufacturers think it is Wi-Fi.

Into the era of full fidelity?

Recently, a company from Switzerland has launched a wireless headset HED Unity, which is priced at US$2,199 (about RMB 15,128) and quickly attracted the attention of the audio market.

From the design point of view, the simple aluminum alloy appearance is quite eye-catching, but that’s all. In the headphone market, it is not uncommon to find more exotic or better-looking designs than this.

So how did HED Unity attract widespread attention? The core is that HED Unity is currently the first commercial mass-produced headset that can realize lossless, high-resolution audio streaming through a local Wi-Fi network.

According to reports, HED Unity supports audio bit rate transmission up to 24bit/96KHz.

Purely from the perspective of transmission bit rate, the parameters of HED Unity are not high, because the latest generation of LHDC-V protocol can already support up to 24bit/192KHz transmission, which is double the wireless protocol of HED Unity.

However, the manufacturers of HED Unity are clearly prepared. For the wireless transmission technology of HED Unity, their explanation is:

Unity’s proprietary Full-Fidelity™ standard delivers unprecedented, truly lossless audio so you hear your music as it is. Immerse yourself in pure sound and rediscover your favorite tunes in all-in-one, all-inclusive, completely wireless comfort.

Hi-Fi is the abbreviation of High-Fidelity, so Full-Fidelity, we may call it Fu-Fi, translated into Chinese means full fidelity.

From the description of HED Unity, it is somewhat Hi-Fi metaphysics, but from a technical point of view, using a Wi-Fi network to transmit audio signals can indeed obtain more stable and faster experience.

But from the point of view of the bit rate, isn’t the adoption of the latest LHDC protocol surpassing the Wi-Fi transmission protocol of HED Unity?

This involves an encoder problem. The LHDC protocol can transmit high-bit-rate audio signals, mainly due to the progress of codecs.

Before sending audio data, the sending end will first compress and package the data, and then The data packet is “thrown” to the receiving end, and then the receiving end decodes and restores the data packet to obtain the original audio data.

In other words, when the bandwidth rate is constant, the higher the efficiency of the codec, the higher the supported audio bit rate, but it will also bring new problems.

If the compression rate is too high, when the audio data is transmitted, once The transmission is disturbed and some data packets are lost, which will directly cause problems such as unstable audio playback.

Source: Android Authority

Therefore, when switching to a high bit rate protocol such as LHDC, the system will generally give a similar reminder: “High bit rate may cause problems such as unstable transmission”.

Under the limitation of the codec mechanism, this problem is currently unsolvable, and high bit rate transmission will also cause a certain amount of data loss during codec. Although it sounds the same to users, the problem of distortion does exist.

The Wi-Fi audio transmission used by HED Unity can theoretically transmit raw data directly end-to-end with strong transmission power and bandwidth, without codec compression.

Therefore, although the transmission bit rate is lower than the latest protocol of LHDC, from the perspective of data restoration, Full-Fidelity may be even better.

However, if you want to use HED Unity’s Full-Fidelity technology, you need to use a dedicated APP, connect to the music library or streaming media service through the APP, and then perform Wi-Fi data transmission.

In addition to Full-Fidelity technology, HED Unity also supports noise reduction, head tracking motion detection and three-dimensional surround sound effects, so it should provide support for spatial audio functions.

Is HED Unity worth the price? Can the so-called Full-Fidelity technology really change the wireless Hi-Fi market?

Wi-Fi Audio: The Future of Wireless Hi-Fi?

Perhaps this is the first time you have heard of Wi-Fi audio transmission technology. In fact, this technology is widely used in the professional audio industry. A

udio equipment used in some large facilities is deployed through Wi-Fi audio transmission.

In the consumer field, Sony and other professional audio companies have launched products using Wi-Fi audio transmission technology.

Taking Sony as an example, its HT-A9 series of wireless speakers launched earlier is composed of a wireless signal transmitter and four wireless audio speakers.

Although Sony’s official information shows that they use a special wireless transmission protocol to ensure the low latency and accuracy of the audio signal, but from the follow-up test results, Sony’s special wireless transmission protocol is actually Wi-Fi.

According to the tests of some professionals, the wireless signal transmitter of Sony HT-A9 essentially builds a hidden Wi-Fi hotspot in the space, and the matching wireless audio system detects the corresponding Wi-Fi hotspot. It will be automatically connected to the network.

At this time, the wireless audio speaker and the wireless signal transmitter form an independent Wi-Fi network.

Because the network is hidden by default, it can only be discovered by using a signal detection device.

From the perspective of the use effect alone, Wi-Fi audio transmission technology is indeed more powerful than Bluetooth.

Whether it is connection stability or bandwidth rate, it is more in line with the wireless connection requirements of professional audio equipment. See less of this technology?

Because of high power consumption, the operating power of the Wi-Fi module is much higher than that of Bluetooth.

For mobile devices, the most direct impact of using Wi-Fi audio transmission is that the battery life will be significantly reduced.

Maybe some friends want to complain, but the Wi-Fi of the mobile phone is not too slow.

That is because the battery capacity of the mobile phone itself is larger than that of most mobile devices, with a capacity of four to five thousand, and the screen, processor, baseband and other hardware Modules are big energy consumers, compared to the Wi-Fi module is just a “little brother”.

But it’s different for earphones and other devices. Even for wireless headphones, the battery capacity generally does not exceed 1000 mAh, and most of them are between 500 mAh and 800 mAh.

After turning on the noise reduction and other functions of most wireless headsets, the battery life will be reduced to about 10 hours, and if the spatial audio is included, the battery life will be further reduced.

In the case of using Bluetooth, the battery life of a wireless headset with full firepower can often not exceed 10 hours.

At this time, inserting a high-energy Wi-Fi data transmission module will only further reduce the battery life of the headset .

In addition to the mobile phone and Apple watch, one more headset that supports Wi-Fi audio will be charged every day.

In addition to energy consumption, Wi-Fi audio transmission also has requirements on the network environment .

The Sony HT-A9 mentioned above is to build an exclusive Wi-Fi network by itself, so as to avoid the signal interference generated by other devices interacting with the router from affecting the audio signal. transmission.

In fact, when there are multiple terminals in a Wi-Fi network, their signals tend to interfere with each other and reduce the bandwidth transmission rate.

It is not clear whether HED Unity solves the problem of signal interference. If HED Unity relies on the existing Wi-Fi network to establish a connection, then the sound quality may not be as good as Bluetooth.

If it relies on a dedicated Wi-Fi network to connect, then it basically loses the ability to use it outdoors (or you need to torture your mobile phone battery life to turn on the hotspot).

In my opinion, the best situation of HED Unity is a Hi-Fi headset that can be used indoors at will.

You can’t hear the difference). Worst case scenario? Naturally, it costs thousands of dollars to buy a wireless headset with poor battery life and average sound quality. For users, it is also a gamble in a sense.

Wi-Fi audio transmission is unlikely to become a mainstream technology for a period of time in the future (unless there are leaps and bounds in technological progress), even though it has many advantages, its disadvantages are also very obvious.

Technically speaking, Wi-Fi audio transmission is not difficult to implement, but from the perspective of user experience, this technology does not meet the needs of most users.

For most people, Bluetooth protocols such as LHDC can already meet the needs of Hi-Fi.

Instead of expecting lossless transmission of Wi-Fi audio, it is better to expect breakthroughs in Bluetooth technology, transducers, and audio materials. It is benevolent.