Smartphones with apt x. AptX HD – truly high-quality sound wirelessly
Are you unhappy with the sound from your Bluetooth headphones? Perhaps the whole point is that your Android uses a “bad” SBC audio codec instead of the advanced LDAC, aptX, aptX HD, AAC?
More and more manufacturers are abandoning the 3.5 mm audio jack in favor of transmitting sound via Bluetooth, but such innovations are not always so useful! It's all about the codecs... and Android doesn't use the best one by default!
A little about Bluetooth audio codecs
SBC (Subband Coding) - this codec is lossy, on this moment used in most cases of transmitting audio over wireless headphones. Most main problem SBC is that the codec distorts the sound very much, more than MP3, so it is clearly not suitable for listening to high-quality audio material.
A.A.C.(Advanced Audio Coding) is also a lossy audio codec, but the sound quality is much higher than SBC.
aptX And aptX HD- an audio codec developed by Qualcomm, so it can be found almost only on devices where it is installed Snapdragon processor. The aptX and aptX HD codec, unlike SBC and AAC, has virtually no loss, audio is compensated and transmitted via Bluetooth.
LDAC- a recently developed audio codec by Sony, which should displace the established SBC codec. This audio codec performs low-loss compression. C Android versions 8.0 Oreo has become part of the system, so LDAC will soon become the standard for transmitting audio over wireless headphones and speakers.
If the headphones only support the SBC codec, then you won’t be able to enable the Bluetooth codec LDAC, aptX, aptX HD!
How to enable the required Bluetooth audio codec on Android?
First, you need to make sure that your headphones or speakers support a more advanced audio codec. You'll have to do a lot of digging on the Internet to figure out what codec they support.
The second condition must be that your Android is version 8.0 or newer.
In order to activate one of the listed codecs, you will need to activate the “Developer Menu”. How to do it? You can read about this in the article "". Or you can watch two videos.
On bare Android:
Once you're in the developer menu, scroll down the menu to "Bluetooth audio codec" and select it.
Select the required codec - LDAC, apt, aptX, AAC, SBC. 
Codec activated! 
You can reboot Android! The sound over wireless headphones should improve!
Do you still have questions? Write them in the comments, tell us what you did or vice versa!
That's all! More useful articles and instructions, read the section. Stay with the site, it will be even more interesting!
Smartphone manufacturers are gradually abandoning a separate headphone jack. So far this is happening sluggishly, but it is obvious that soon there will be no mini-jacks at all. It's no longer in the iPhone 7 and 7 Plus - and if Apple does something, it becomes standard.
You can listen to music without a separate headphone jack in two ways: via USB (Lightning) or via Bluetooth. The first option looks like temporary “crutches”, while not everyone still has wireless headphones. The future belongs to the second method.
“Bluetooth headphones are comfortable, but sound mediocre” is a stereotype.
There are technologies that wirelessly transmit high-quality sound that is pleasant to the average human ear. In this article we will talk about the protocol AptX, widely used now, and its improved version, which is already being slowly introduced.
Why did Bluetooth headphones sound bad?
The stereotype about the poor sound of wireless headphones appeared for a reason. They could be as advanced as they wanted in terms of hardware, but the limitations of Bluetooth turned high-quality sound into “brown”.
Blue tooth is a universal, widespread and economical technology, but its data transmission channel is very narrow. Therefore, you can’t just put Lossless into your headphones – you need to compress it.
The most common compression profile used in all smartphones is A2DP. Its base codec is called SBC. It greatly reduces the amount of data transferred, but the sound also becomes mediocre. For example, to simplify calculations (and therefore increase the speed of information processing), all frequencies above 14 kHz are simply cut off. Because of this, even with the same bitrate, the quality is worse than in MP3. And this format is far from standard.
The AAC codec is not so barbaric - the sound quality is already better than in MP3, but still worse than in CD.
AptX sounds almost like a CD
Here we come to the technology for which we gathered. AptX transmits audio over Bluetooth with a bitrate of 352 kB/s and does not cut off the range - it is 10 Hz - 22 kHz. This is achieved through complex algorithms, so the codec requires a processor that is three times more powerful than SBC. For modern smartphones This has not been a problem for a long time, so AptX works on all Android devices.
However, it is required that both the smartphone and headphones support the technology.
Otherwise, compression will be performed through the base codec.
AptX is indeed comparable to CD quality, but still inferior. 4:1 compression is applied. That is, the range is narrowed four times compared to the original, high and low frequencies. On the official website you will only find the wording “near-CD quality” - “close to CD quality”. Close, but not the same.
Before and after compression
However, look around - the majority listen to music on VKontakte through supplied or cheap headphones, not paying attention to the subtleties. They would live quite well with AptX.
AptX HD sounds better than CD
For those who still need better sound, we came up with AptX HD codec. Now let's figure it out what it is. The audio stream is also compressed four times, but the bitrate has increased from 352 to 576 kB/s. The official website promises us “quality better than CD.”
True, the technology is still very poorly distributed. Just as in the case of AptX, you need the codec to be on both the smartphone and the headphones. The list of phones supporting AptX HD is sparse:
- Vertu Constellation Octane
- Luna TG-L900S (have you ever heard of this one?)
LG Tone Active+ is one of the few headphones with AptX HD support
It is unlikely that you will buy any of the last two smartphones. To pair with the LG flagships, you will also need to purchase one of the four available headphones from the same LG and Audio-Technica. We recently reviewed one of these headsets -.
What does all of this mean?
The fact that wired headphones will soon fall into oblivion. Of course, not in the next year or two, but in the foreseeable future. This largely depends on how soon the technology comes to computers. After all, people listen to music not only from smartphones.
The main thing is that the necessary technology to eliminate wires already exists. It’s hard to imagine a person who needs even better quality or who considers wired headphones more convenient than wireless ones.
Of course, there will always be audiophiles who will listen to vinyl and use audio systems that cost a lot of money. AptX HD is not for them. This is a mass technology that will certainly become widely used.
©Hello to all lovers of good sound! In this article I would like to talk about high-quality sound using APTX and SBC wireless methods.
Sound via Bluetooth good sound becoming more and more popular, the "APTX" brand began to appear on more products.
But how does Bluetooth work with sound and what does it do?
Let's figure it out.
If you bought any for yourself wireless bluetooth audio products in Lately, headphones or wireless speakers, or even a smartphone, then you may have seen mention of APTX.
APTX promises "CD-quality sound, but over Bluetooth." These comparisons always confuse me; I suspect that there is something hidden somewhere.
But audio over Bluetooth is certainly compressed—after all, some of the data is discarded. You can hear it immediately as soon as you put on your headphones or turn it on.
Audio via Bluetooth does not sound as good compared to other wireless methods or wired.
So can APTX help improve Bluetooth sound? And if so, how?
Before we talk about APTX, we have to start with digital audio and Bluetooth connectivity. Digital audio is a set of samples, so sound wave looks like at a certain point in time. Instead of a stationary wave of sound, it is a series of snapshots.
With enough of these snapshots, or "samples", a playback device (DAC, for example) can convert them back into a smooth sound wave.
Audio on a CD has 44,100 vibrations per second, and each sample has a value somewhere between 0 and 65535 (also called "16-bit"). So, in other words, there are 44,100 snapshots per second, and each snapshot has one of 65536 possible values.
I showed all this in a simplified way, but this is just the beginning.
The 16-bit/44kHz CD speed translates to about 10MB per minute for stereo.
Even though the data these days is still huge, the flow cannot be handled over the Internet, or stored on a portable device. 
So the good ubiquity of a compressed audio format such as MP3 is a plus. Considering that you theoretically cannot hear, the difference using a method called "psychoacoustic modeling" mp3 file sizes will be much less than about 1 MB per minute.
But compressed format sound, for example mp 3 often does not sound as good as the uncompressed format flak, ape, vav. But you can notice the difference even if you listen through the cheapest headphones.
Bluetooth is a way wireless transmission data, but low power to allow two devices to easily transfer data over short distances. Like all wireless methods, it has limited bandwidth. As Bluetooth standard Since it was first introduced, the size of wireless data transmission has increased.
However, it does not have powerful bandwidth such as Wi-Fi.
For transmission bluetooth sound uses "SBC", which stands for encoding. Compressed Audio, such as MP3, which is compressed using Bluetooth.
Moreover, the MP3 format was not designed for perfect audio fidelity. MP3 was designed to be used as a small computing power as small as possible. If you are using Bluetooth headset to give your voice to phone call, SBC will handle it just fine, and will also handle mp3s just fine. But here's the music flac format, wav, ape, a lot of things are lost as a result of pairing with . 
Worse yet, there are several SBC tiers, and as you can guess, the smallest MP3 wins.
So if your new phone has SBC with high speed but your headphones can't, then you get that maximum speed headphones can handle (or vice versa).
And remember that Bluetooth compression is in addition to any compression in music. So if you have MP3 files on your phone, then those MP3 files will be decoded and then re-compressed with a different lossy codec (SBC) to be transferred to the wireless headphones. So transferring music via Bluetooth is not for.
APTX
APTX is also compression; it's just a different type of compression. MP3 uses the above-mentioned psychoacoustic modeling system to extract data, APTX uses "ADPCM time domain".
Let's go to www.aptx.com
How does APTX work?
APTX Technical Details
The aptX® codec has been the secret weapon of the music industry, public broadcasters and 
film studios have been delivering CD-quality sound via Bluetooth® for years because of it.
Bluetooth® is limited to the maximum available throughput, so is not always suitable for delivering high-quality audio.
aptX® technology revolutionizes Stereo Bluetooth® listening by significantly reducing data transfer rates without sacrificing audio quality or latency issues.
So with aptX® you can enjoy pure wireless CD quality.
This is what is written on the website www.aptx.com
Simplified - the ADPCM version uses fewer bits per sample.
CSR, the company that currently holds the APTX patents, is making a big contribution to its technology.
The trick is that both products—the phone and the headphones, for example—need to have APTX to get the maximum . If only one has it and the other just runs SBC, then the connection will work, but not 100%.
By the way, there are many products that have APTX, but not Apple owners.
Samsung, HTC, Motorola and phones have it, as well as numerous Chinese headsets/speakers as well.
Is it worth it?
Well, maybe. During testing/listening, most bluetooth headphones and the speakers sound, frankly, terrible. The transmission medium is not an issue, but they are just poor sounding headphones/speakers. There are also some good sounding headphones with SBC or APTX functionality, but their price leaves much to be desired, such as the backbeat pro.
Some forum posts claim that APTX is a huge step.
Will APTX technology have better sound quality?
Yes, better than SBC with better compression. But the problem is, as you know, if you have equipment with APTX technology, then it again compresses.
However, APTX seems to offer better sound quality than SBC.
conclusions. Wireless technologies aptx communications and sbc offer pretty good and convenient solution, but the sound quality is very controversial, and if you have good audiophile hearing, then wireless connection It definitely won’t suit you (I personally hear the difference).
However, the listening results ordinary people(non-audiophiles) 7/10 - could not distinguish between wired and wireless sound (blind listening).
Are these useful or not? wireless technologies sound transmission - it's up to you. I personally think that neither APTX nor SBC are still ready to transfer data in uncompressed flak, vav, ape, (compressed) formats, but for compressed files mp3 it's good. Easy way out not in this solution. On the one hand, the wireless type of communication is very convenient, there are no wires, a long distance from the source, good quality sound in mp3 format, but on the other hand I did not like the sound quality in uncompressed formats. In the future, I think the quality will change wireless audio to the best.
I hope the article helped someone
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The latest flagships and music smartphones often feature AptX support. Let's figure out 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 is compression audio track when transmitting data within Bluetooth bandwidth conditions.
Smartphone manufacturers' abandonment of the headphone jack is becoming an increasingly popular solution and one of the key trends for the coming years. Lack of 3.5mm jack Apple smartphones motivates other manufacturers to switch to wireless audio transmission systems.
Stereotype about the insufficient quality of music in wired headphones is associated with a limitation in frequency transmission in A2DP technology, which distorts the sound original file. AptX correctly transfers files with high bitrates. Modern way compression of Lossless files allows you to transmit high-quality sound using . Considering all the advantages, the codec is predicted to become widespread and widespread.
Advantages
The principle of operation of the codec is that it allows you to compress an audio file to transmit data with a bitrate of up to 352 Kbps. Modification from Qualcomm - AptX HD - supports bitrates up to 576 Kbps.
To transmit 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 sound quality almost equal to CD, but not yet equal 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 reproduce the received data, thereby loading the hardware.
Collateral correct operation All links in the audio chain is codec support on both devices - both the smartphone and the 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.
I'm tired of headphones with a constantly coming off jack and a broken computer socket. I decided to give up wires and started looking at an FM headset, but based on the reviews I realized that my option was bluetooth.
However, there are also difficulties here.
An FM headset is essentially an FM receiver and transmitter. There is no encoding before transmission and no decoding of sound after reception, which means there is no lag between the sound and the picture on the monitor.
In the case of Bluetooth, between transmitting audio to digital format and by its reception + decoding to the level of sound vibrations passes certain time. And what weaker version Bluetooth, the greater the lag between the sound and the picture.
While studying the topic, I came across information about profiles and codecs supported by bluetooth versions. As it turned out, having the same set of supported profiles, Bluetooth gadgets from different manufacturers may behave differently in terms of audio lag from video. The whole point is in the codecs for encoding and decoding the stream.
Today, the most advanced, high-speed codec is the Aptx codec, implemented in CSR8645 chips.
Based on this chip, bluetooth modules CSR8645 with Aptx support are produced in China.
I ordered one for myself at a price of $5.2 per free shipping in our region at the time of purchase.
However, when I received the parcel I was very surprised - I ordered this one 
and got this: 
Those. The package contained the module I needed, but it came with an external two-channel amplifier at a price without it. 
I didn’t start an argument out of modesty), but they could have fired someone. Thank you for the mistake, although not cleverly.
Now let's talk about everything in order.
Technical characteristics of the bluetooth module:
1. bluetooth version: 4.0
2. Supply voltage: DC3.6V-4.2V
3. supported Bluetooth protocols: HFP V1.6/ V1.2 A2DP/ AVRCP V1.4/ HSP V1.2
4. Working current: ≤30mA
5. Standby current:< 50uA
6. Temperature Range: -40~+80 Celsius
7. Transmission distance: >10m
8. Transmitter power: CLASS1/CLASS2/CLASS3, 9dbm (Max)
9. Frequency Range: 2.4GHz ~ 2.480GHz
10. External interface: PIO/ SPI/ I2S/ PCM/ USB
11. audio codecs: AAC/ MP3/ SBC/ APTX
I looked into the datasheet and discovered several more very interesting functions:
1.Possibility of connecting two microphones
2. 5-band customizable equalizer
3. noise reduction of microphone inputs, including wind!!!
4.Voice recognition for hands-free function while answering a call
5. Connect two phones at the same time
6. possibility of programming
7. Attention: charge control of the lithium battery!!!
Thanks to its very modest dimensions (27*13.3 mm only for Bluetooth and 29*30.5 mm with an amplifier), the module can be installed almost anywhere.
Pin assignment: 
I can't say anything about programming. Allegedly, this requires some kind of specific programmer. But this function, like most consumers, is unlikely to be of interest to me.
I also couldn’t figure out the equalizer, but I believe that it exists - the manufacturer of the Cambridge Silicon Radio chip values its reputation. Most likely the equalizer is activated a certain combination buttons, but even with default settings the sound is simply excellent, and its settings can be done on the source (computer, phone, etc.)
The internal battery charge monitoring circuit can provide charging current at the level of 200 mA, for higher currents an external transistor is required with a connection according to the datasheet. When the battery voltage drops to 2.8 volts, the controller turns off the power.
The connection diagram for external components to implement a headset for a telephone is extremely simple: 
With the connection of LEDs, battery and control buttons, everything is very clear. There are some reservations about connecting headphones/speakers (hereinafter referred to as N/A) and microphones - each N/A is connected with two separate wires; ground wires cannot be combined, otherwise the excitation and background will be half-limited. At first glance, it is not very convenient, but there is good channel isolation and no interpenetration of signals from channel to channel. A D/N connection with a resistance of 16-32 Ohms is allowed.
Since electret microphones are now used, power is required for their operation, which is implemented by the output of the Mic Bias module.
In my case (Bluetooth module on the power amplifier board), all the necessary external components are already placed on the power amplifier board - LEDs with current-limiting resistors, external circuits of one microphone (if you need a second one, you will have to solder similar circuits directly to the Bluetooth module).
The package sent to me does not have a POWER button. The module is in sleep mode by default and to activate it, press and hold the PLAY button for a few seconds, after which the module turns on and connects to the signal source (another Bluetooth device).
Thus, only five buttons are needed for control - Play, Vol+, Vol-, Track+, Track-.
One pin of each button is connected to the corresponding pin on the board, and the second pin of each button is connected to the COM pin. In test mode, the wire soldered to the COM point simply connected with Play, Vol+, Vol-, Track+, Track-. The controls work great.
Pairing with a phone and current consumption in standby mode. 
What can I say about the stereo amplifier?
It is built on two single-channel audio amplifiers HT6872. Both channels are completely independent of each other. The speakers, already with a resistance of 4 ohms, are also connected each with their own pair of wires. This is convenient for using a module with an amplifier as a basis for Bluetooth headphones or speakers. In other cases, where the use of the total mass of two channels is required, additional circuit solutions will have to be used. Each channel develops a power of 3 watts.
It is possible to power a module with a power amplifier with a voltage of up to 6.5 Volts - there is a 7536 stabilizer on the amplifier board. The amplifier is powered from the input voltage (up to 6.5 Volts), and the bluetooth module is powered from the received 3.6 V.
There are also Bluetooth modules on sale with a different amplifier. It uses one microcircuit and requires three wires to connect the speakers.
The sound quality is simply excellent, I was very pleased with the low frequencies, the microphone is sensitive. At a distance of one meter from the microphone, the subscriber hears me perfectly. The communication range is about ten meters.
“On-the-knee” design and the results of measuring current consumption at maximum and average volume.
I apologize for the quality of the photo - the camera has died for a long time.
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