In the latest flagships and music smartphones AptX support feature often appears. Let's understand what it is and how it works.
What is aptx?
AptX technology allows you to get truly high-quality sound in Bluetooth headphones. Its essence lies in the compression sound track when transmitting data in terms of width bandwidth bluetooth.
Moving smartphone manufacturers away from the headphone jack is becoming an increasingly popular decision and one of the key trends for the coming years. Lack of 3.5mm jack Apple smartphones motivates other manufacturers to move to the system wireless transmission sound.
The stereotype about the insufficient quality of music in wired headphones is associated with a limitation in the transmission of frequencies in A2DP technology, which distorts the sound original file. AptX transfers high bitrate files correctly. Modern way Lossless file compression allows you to transfer high-quality sound using . Given all the advantages, the codec is predicted to be massive and ubiquitous.
Advantages
The principle of the codec is that it allows you to compress an audio file for data transmission with a bit rate of up to 352 Kbps. Modification from Qualcomm - AptX HD - supports bitrate up to 576 Kbps.
To transfer data to headphones or an audio system, an audio stream compression method is used, which requires high performance from the receiving device. The available frequency range ranges from 10 to 22,000 Hz, providing a sound quality almost equal to CD, but not yet up to vinyl.
Features and requirements
An important factor when choosing a device with AptX technology is its autonomy and performance. The codec requires a lot of energy to decode and play the received data, while loading the hardware.
pledge correct operation of all links in the audio chain is codec support on both devices - both smartphones and headphones. In this case, the sound quality will be as high as possible. If one of the gadgets does not support the codec, the sound will be provided standard driver, therefore, it will not be possible to evaluate the technology. Note that most modern flagships already support AptX: Samsung Galaxy S7 and S8, OnePlus 5T, LG G5 and G6, Huawei Nova 2 and others.
We are surrounded by hundreds of amazing and unique phenomena, we encounter them every day, but we don’t even think about how they work. One such phenomenon is sound.
For us, sound is air vibrations perceived by the ear.
Sounds are made up of a mixture of vibrations of varying strength and frequency. Human vocal cords can vibrate, strings in musical instrument, any surrounding objects further vibration spreads in the air and is transmitted to the eardrum in the ear, and our brain perceives these vibrations as sounds.
But how does it work with digital audio?
How does sound go digital?
The sound has an analog nature, it propagates in the air space. Air vibrations are converted into electrical vibrations through a microphone, and then a special transducer captures them and encodes them in a digital language.
It is in the process of encoding that the further quality of the digital copy of the reproduced sound is set. The smaller the sampling step when digitizing sound, the more information about the sound will be converted to digital format.
How digital music is stored
Now the vast majority of music is stored in digital form because it's easier, more convenient and more reliable. Once encoded according to a certain algorithm, the file will not lose its properties and will not lose quality.
Initially encoded sound quality cannot be significantly improved with programs, speakers or headphones.
Digital sound can be copied indefinitely, while its properties are not lost, and the quality remains unchanged.
How digital audio is reproduced
To transfer to headphones or speakers, you need to reverse the conversion process.
A digital-to-analog converter (DAC) in one form or another is present on all smartphones, players and computers. It is needed to translate digital music to analog format.
A sequence of zeros and ones, understandable to computers and smartphones, turns into a set of electrical signals that make the speakers make a sound.
The more powerful the DAC, the better the sound quality is at the output. Majority modern electronics rarely equipped with serious converters. The appearance of a DAC from a famous brand in a smartphone is always a big event.
Real audiophiles prefer specialized, expensive music players, such as the . This device is equipped with simply royal DAC High Quality, as in serious Hi-Fi equipment
Essentially this hi-fi player And powerful amplifier in one device that can play digital music up to 32bit/384kHz encoded. KANN delivers up to 7V on a balanced output, this will not only "rock" high-impedance headphones easily, but also allow you to connect low-impedance speakers.
KANN is also equipped with a four-pin 2.5 mm balanced output. This solution makes it possible to suppress almost all noise and obtain a large amplitude by doubling the transmitted signal.
What happens next
Further, everything is simple: electricity from the converter passes through the amplifier and is fed to the speaker contacts. Next, the current enters the coil, which pushes the membrane. The change in the directions of the applied current depends on the frequency of the sound vibrations of the music (or other reproduced sounds).
FACT: during playback musical composition the alternation of the direction of the current can occur more than twenty-five thousand times per second.The volume of the sound is directly proportional to the strength of the current supplied to the coil. The higher the voltage, the higher the current in the coil. From this listening to music on high volume drains the battery of the mobile device faster.
What's inside the speaker
We all know that two magnets at a certain distance from each other begin to interact with each other: attract or repel. The same phenomenon is used in any audio speaker.
Inside the speaker is a permanent magnet, made in the shape of a circle. In the hole in the middle and place a coil of copper wire, which is connected to the membrane (light and rigid cone). On conductor with alternating current operates in a magnetic field variable force, which moves the coil and the diffuser attached to it.
The movement of the membrane creates compression and rarefaction of the air, which contributes to the appearance of sound.
FACT: the principle of operation of the speaker works in reverse side. If you create vibrations in the headphone coil, then the field of a permanent magnet will create a current changing direction inside it. If you connect a headphone to the computer's audio input, you get a microphone.In computers, smartphones, headsets and headphones, one is most often used to save space. broadband speaker, which is responsible for reproducing the entire audio range.
There is no fundamental difference between a speaker in a column or a headphone. The differences between them are in size and soundproofing.
How about bluetooth headphones?
Another link appears in the chain between the digital-to-analog audio converter and the speaker. Although the presence of bluetooth does not affect the principle of operation of the speaker, very often when transferring music without wires, the quality becomes worse.
To get around this annoying limitation, you can use the compact one from Astell&Kern. It allows you to turn wired headphones wireless.
Any audiophile will confirm that wired headphones or speakers sound clearer and more detailed, the music played through them is richer. This is due to the fact that the audio is re-compressed for transmission via bluetooth.
In every second of time it turns out to fit only limited quantity information about the sound, as a result of which some details are lost.
FACT: Packet loss and minimal decoding time degrade audio in most Bluetooth headsets.Previously, a codec was used to improve the quality of the sound transmitted via Bluetooth. aptx. His further development became the format aptx HD. It supports audio transmission high definition and today is the only way receive good sound when using bes wired headphones. Of course, for this, both the player and headphones must support aptx HD.
Who helped us figure it out
Not all modern flagships support this cool codec. Only a few manufacturers rely on sound in single models.
In the player market, aptX HD technology is more common; Astell & Kern has become a pioneer in this direction. aptX HD is already supported on the AK380, AK320, AK300 and AK70 models. It is distinguished by the presence of a newfangled option and a fresh
Wherever we read anything about Bluetooth, in addition to this name itself, all sorts of incomprehensible numbers and letters constantly come across. Now “in vogue” is the designation aptX HD, which has recently replaced the shorter aptX.
It is clear that the prefix HD stands for " high definition “But how High is it, and what does this very aptX mean? And just how is aptX different from the new aptX HD?
In general, let's understand.
what is aptX?
aptX is digital technology(it is also the so-called Bluetooth codec), which allows you to transmit audio signal in 16-bit/44.1 kHz quality at 4:1 compression level and 352 kbps bit rate .
This is in short. Actually, you can easily find all this in any description of the aptX codec. And it will also, for sure, be written that thanks to aptX, your smartphone, laptop, AV receiver can transmit sound via a Bluetooth channel “with a quality close to CD”. Which already sounds much more inspiring than boring spec numbers.
In general, aptX technology is able to provide CD-like sound quality for music and, as a rule, does.
Another thing is to distinguish between "close" and "true" CD-quality. And these two “qualities” differ just in the level of compression (compression), which in aptX, like in any other Bluetooth codec, is used to reduce inevitable delays. arising from the encoding and transmission of stereo sound. Simply put, aptX always compresses the signal before sending it, and the receiving device (headphones, external speaker, etc.) decompresses this signal during playback. It takes time, otherwise - nothing.
When you listen to music, then any delays in the operation of devices do not matter, and you simply do not notice them. Moreover, when transmitting a wireless audio signal, even between your smartphone and headphones, delays can be quite significant. But when you watch a video, any delays appear almost immediately. Actors suddenly stop “getting into words with their lips”, the sound of the stream clearly does not match what is happening on the screen, etc. If you watch Netflix or other services streaming video, then you all know this too.
Therefore, specifically for the transfer of sound to video (and for all other cases where the minimum delay is important) was developed special version codec - aptX LL, where it means Low Latency, i.e. "short delay". aptX LL also delivers that "near-CD" sound quality, but reduces the time it takes to transfer and decompress data to 32 milliseconds. Technically, this is also a lot, but the user’s brain no longer notices such a delay. Therefore, aptX LL is used in gaming headphones and headsets, in which the minimum delay is even more important than sound quality.
New mobile headset Sennheiser MOMENTUM Free with aptX Low Latency codec support
Now we can summarize: with aptX, Bluetooth headphones, headsets, external speakers, and other devices sound better, plus aptX also works more efficiently than most other Bluetooth codecs, because aptX support is provided in almost every device that sends and / or receives audio via Bluetooth - channel.
what is aptX HD?
aptX HD is the same Bluetooth aptX codec, but improved and which allows you to transfer audio signal in 24-bit/48 kHz quality at a compression level of 4:1 and a bit rate of 576 kbps.
Yes, numbers again. But there are still not many of them, and, as you can see, they are a little different. It's not hard to see that aptX HD is capable of transmitting more than quality sound and at a much higher speed (lower latency). And files in 24-bit / 48 kHz format are already real HD-sound, which is so appreciated by the owners of expensive wired headphones, and in which there is very little background noise and even the smallest nuances of sound are clearly audible.
It is worth noting that some “musical” smartphone models (for example, LG V series) can also transmit such sound, but only in wired mode, i.e. through a 3.5 mm headphone mini-jack, and 24-bit/48 kHz quality is actually the limit for them.
However, there is a difference between wired 24bit/48kHz and wireless (i.e. Bluetooth) 24bit/48kHz. And it consists in signal compression. From the usual aptX, the new aptX HD differs more efficient algorithm compression (in the descriptions it is also called "soft"), but not flawless.
In the sense that any compression always adds extra noise and hiss to the signal. And you hear it, although you do not always understand what it is and where it comes from. By the way, rock guitarists often use signal compression intentionally to give the guitar sound an additional "roughness" and "fuzziness".
For the aptX HD codec, a special, “soft” codec was developed specifically to minimize any “roughness” and “fuzziness”, but even aptX HD cannot completely remove the excess noise resulting from signal compression from the audio stream.
Secondly, as we have already noted, if Apt X transfers data at a speed of 352 kbps, then aptX HD audio transfer rate is increased to 576 kbps. And taking into account the fact that the more kilo-, mega-, etc. bit second transmitted, the better, the more high speed the speed just allows aptX HD to manage with a “softer” compression algorithm.
Total : it turns out that compared to just aptX, the new aptX HD in wireless mode can transmit higher quality audio with lower latency and more gentle compression, and thus, as it were, brings us closer to the sound quality that is achievable only with wired transmission audio signal.
aptX HD support
... - it, of course, is still in short supply. Since aptX HD is also a Qualcomm development (like regular aptX with all its variations), this codec is only supported by hardware and/or software solutions Qualcomm. And on this moment time, it is still only the CSR8675 audio processor with Bluetooth 5 and the system active noise cancellation via Bluetooth and Qualcomm TrueWireless Stereo audio transmission technology. But they also provide backward compatibility, that is, support for aptX.
The first smartphone to implement aptX HD support was the G5 from LG, with the release of which the South Korean company actually launched and led the process of promoting a new codec on the market. mobile devices custom class. aptX HD also works with LG V20, the LG G6 and LG V30. Following LG, other brands actively began to introduce aptX HD. In particular, Sony Xperia smartphones XZ1 and XZ1 compact), OnePlus (OnePlus 3, 3T and 5 smartphones), as well as Sharp, Luna, and a number of Chinese manufacturers Android smartphones.
LG G6 and Audio-Technica Wireless with AptX HD Codec Support
On the other hand, that is, from the side of playback devices, you can find aptX HD in Sony headphones, Audio-Technica, LG and other less famous brands. The number of such devices will grow as manufacturers release new models. And they will release them, since aptX HD, as we have already found out, really allows you to improve the sound quality. But how much, in each individual case, the user has to determine independently.
AptX HD Bluetooth: what is it and how to get it? June 8th, 2017
The aptX HD protocol is designed to provide Hi-Res audio transmission over Bluetooth. Here you will find everything you need to know about it and how to use it.
During long way we have learned one wisdom: many people are willing to sacrifice sound quality for the sake of convenience. Let's take, for example, wireless headphones. They can rarely compete with good wired ones, but they are much more convenient with them.
However, some time ago the pendulum swung in the direction of quality growth. The most striking examples of this trend can be considered the revival of vinyl (that's where there is no talk of convenience at all), as well as the growth in popularity of Hi-Res audio. So, is there a way to combine usability and sound quality?
Developers from Qualcomm are sure of it. Earlier this year, they introduced the aptX HD codec, which allows streaming wireless channels music in 24-bit Hi-Res audio format. Thus, devices with Bluetooth enabled(e.g. portable speakers) can theoretically sound much better.
What is good about aptX HD? How to get it and what devices support it? Now we'll find out.
What is aptX Bluetooth?
To understand what aptX HD is, you first need to remember the "classic" aptX. This is an audio coding algorithm created in the 80s and widely used by filmmakers and radio stations. Today, aptX is closely related to Bluetooth, which is found in many computers, smartphones, AV receivers, and other consumer electronic devices.
The main advantage of aptX is its ability to transmit a full-band music signal in near-CD quality (16 bit/44.1 kHz). This is "close", not true CD quality, since aptX uses compression to reduce latency due to encoding and transmission. Classic aptX uses 4:1 compression and a bit rate of 352 kbps.
What is aptX HD?
Now let's go directly to aptX HD. Basically, it's aptX, upgraded and improved to make it possible to stream higher quality music.
Its development was stimulated by the rise in popularity of Hi-Res audio; it supports formats up to 24-bit/48 kHz, the compression ratio remains the same (4:1), and the data rate has increased to 576 kbps.
How much the sound quality will be comparable to Hi-Res signal transmission over a cable remains to be seen; however, Qualcomm proudly waves the "better than CD" flag.
What do you need to evaluate aptX HD?
It takes quite a bit to use aptX HD. First of all you will need the right equipment. It's about about the CSR8675 Bluetooth audio system on a chip.
It not only supports full 24-bit audio, but also provides better quality digital processing signal compared to its predecessors. Qualcomm promises to improve the signal-to-noise ratio through encoding and decoding and reduce distortion, especially in the 10-20 kHz range.
The need for a dedicated chipset means that you will need to get compatible devices to use aptX HD: there are no firmware upgrade options. There are no prospects for any "rescale" of the audio signal.
But you don't have to worry about backward compatibility: Devices with aptX HD will support all headphones and smartphones with "classic" aptX.
What devices support aptX HD?
LG G5 puts sound quality on the map with its modular design including an external DAC
aptX HD codec was announced in January 2016. It will be used in Android smartphones and tablets, as well as in portable media players.
The first smartphone to support aptX HD was the LG G5 released last year. He was followed by his brothers - G6 and V20.
Except them, aptX technology HD is also supported by high-end smartphones - Vertu Constellation Octane and Luna TG-L900S - which can hardly be called widespread.
Among manufacturers of portable music players aptX HD's biggest fan is Astell & Kern. New codec supported by its AK380, AK320, AK300 and AK70 players, as well as the XB10 amplifier/DAC.
