How to enable Xiaomi aac codec

Bluetooth CODECs: SBC, AAC, aptX, LDAC: Parsing

The headphone jack has completely disappeared from smartphones. There are more and more wireless headphones, which means it’s time to talk about Bluetooth codecs. over, the topic is full of controversial issues.

Is it true that the SBC codec is that bad? What is the popularity of AAC? LDAC is marketing bullshit? And what is the new king of codecs preparing for us from Bluetooth itself?

And also today we will tell you how other pieces of iron inside the headphones affect the sound quality? And listen a little on the example of new headphones

Codecs and compression

People often compare codecs by only one parameter. the maximum bitrate. In theory, the higher the bitrate, the more data is transmitted and the better the quality.

For example, look at the picture, LDAC has a maximum bitrate of 990 kbps, because this is much better than 250 kbps for AAC?

But this is not always the case, because sound quality and connection stability are influenced by many more factors than just bitrate. So today we’ll dig deep

Let’s take a look at the line first. What do we have?

AAC, SBC are the most popular and massive. There is also LDAC with a high bitrate. And also aptX and, more recently, the new LHDC, which is being promoted by HUAWEI. And he’s got some fancy chips.

In general, it is important to say that not only the codec is responsible for the sound. The engineering solutions themselves and the components in the headphones are also very important. By the way? new HUAWEI headphones we will test FreeBuds 4i today. For example, here it is responsible for the sound: a 10 mm dynamic radiator, this is a lot. Yes, and with a polymer diaphragm.

SBC. low-complexity sub-band codec

Let’s start with the SBC codec. This is the standard codec for all Bluetooth audio devices. It is supported by all headphones and players except for Apple devices, because Apple only works with the AAC codec. What else will we talk about.

SBC has a lot of advantages. First, it is a codec that is very easy to calculate. In order to compress audio, all it does is split the audio into several frequency bands: low, medium high frequencies, and then it starts to quantize, that is, round the values, thereby saving bits of information.

He does it from the lower frequencies to the upper ones. And if the entire bitrate was used for the lower and middle frequencies, the upper frequencies will be “cut off” (there will be silence instead). If in a simple way he leaves the bass, and cuts the top. And the less bitrate we allocated to the codec, the more frequencies will be cut off.

Bluetooth device connected but no sound issue fixed 100% | AAC codec compatibility issue fixed

For example, on this spectrogram, compressed and uncompressed fragments alternate. In the sections encoded in SBC, you can see how the codec cuts quiet sounds above 17.5 kHz and does not allocate bits of information for a band above 20 kHz at all.

SBC can operate in a very wide range of bit rates from 10 to 1500 kbps, and the quality naturally depends on this. At 328 kbps the sound is excellent, almost indistinguishable from the original, but already at 240 kbps the sound is mediocre.

At the same time, you will not find SBC at a maximum bitrate of 1500 kbps anywhere, because all headphone manufacturers cut the bitrate to 328 kbps. Why is that? It’s likely that you’ll have connection problems.

over, the SBC codec does not have fixed profiles, there are only recommended ones. Therefore, headphone manufacturers can set any bitrate limits they want. Hence the bad reputation of the codec.

But if you want, you can configure the codec in such a way that it will have low delays and high sound quality. The flexibility of the SBC codec is both its advantage and disadvantage at the same time.

Our headphones also have it. Let’s listen! In fact, one of the important things about codecs is their processing algorithms. And if the headphones also have noise reduction, as in ours, then a high load falls on the processor. For this, there is a special chip from BES Technic, but let’s move on to this.

FreeBuds 4i also support the second popular AAC codec. Let’s deal with it.

AAC. Advanced Audio Coding

The second most popular codec is AAC. This is not surprising, because this is the default codec for iOS and MacOS devices.

AAC, unlike SBC, is a codec that is difficult to calculate. And all because it uses a serious psychoacoustic model to compress the audio signal. Um… Serious what?

Yes, there is such a science of psychoacoustics. It studies how a person perceives sounds from the point of view of physiology and psychology.

A simple example. If you simultaneously clap your hands and pierce a balloon with a needle, then you probably won’t hear a clap. Because a louder sound, and even at a similar frequency, will simply mask a quieter sound. This property of human perception was very helpful to the creators of audio codecs. After all, everything that a person does not hear anyway can be safely deleted.

The first successful audio codec that used the psychoacoustic model was MP3. And in the AAC codec, this model was pumped even more, so AAC at a bit rate of 256 kbps sounds as good for a person as MP3 320 kbps. And if you take into account, the bitrate, in principle, cannot be low. It varies from 256 kbps to 320 kbps, it turns out that AAC, in principle, cannot sound bad and under any conditions it will do SBC. So after all?

Unfortunately no. Since AAC is a difficult codec to calculate, it needs a very good decoder to make it sound good. For example, their own, which is called Apple AAC. By the way, all companies pay license fees for using the codec. Well, actually, we pay.

Requires licensing and royalties: 15,000 lump sum (or 1,000 for companies with fewer than 15 employees) 98 for the first 500,000 devices.

In Android devices, at best, the second-best encoder is used. Fraunhofer FDK AAC, but in fact you don’t understand what. Because the quality of AAC varies greatly. Take a look at the test from SoundGuys.

The purple line is a test file. And you can see that the iPhone (blue line) cut off much less information than Android devices.

On the other hand, look at how Android smartphones with SBCs of everyone else are doing with the AAC codec, including the iPhone.

So on Android you never know how good AAC will sound.

over, there is another problem. Since the codec is heavy, the delays also increase.

As a rule, AAC has slightly higher delays than other codecs. Although in fairness, the delay is more dependent not on codecs, but on the device on which decoding takes place.

�� Лучший Bluetooth кодек без маркетинговой чуши! APTX, LDAC, AAC и SBC.

One of the features of FreeBuds 4i is low latency. It is implemented at the expense of its own aglorhythms. But it works better as expected only with Huawei smartphones. By the way, there is an instant connection here.

And even if you are already listening to an AAC file on an iOS=device, you still need to decode it from AAC first, and then encode it again into ACC in order to transfer it over the air. At the same time, the quality will drop a little. This is necessary so that other system sounds, such as notifications, can also be mixed during music playback.

FREEBUDS4i

So what is the best codec to use for Android? SBC or AAC?

The answer is simple, it depends on the device and headphones.

Take, for example, the new TWS headphones from HUAWEI. FreeBuds 4i. They support both SBC and AAC. But HUAWEI clearly wants you to use AAC. And all because the SBC here is cut to 220 kbps, and at this bitrate the SBC produces a very mediocre sound, in the good traditions of the first Bluetooth headsets.

But AAC, on the contrary, sounds and works perfectly. But this is achieved at the expense of hard hardware power. a separate chip with an integrated encoder and DAC BES2500Z from BES Technic. There are even his photos, check it out.

This thing pumps AAC to the maximum here: it processes audio, encodes, decodes, reduces delays, reduces power consumption, and so on. For example, the technology for synchronizing audio and video when watching YouTube works here and there is no delay at all.

Also, these headphones last longer than all HUAWEI headphones. 10 hours of continuous playback without a case and 22 hours with recharging from a case. But that’s true with noise canceling turned off. With it turned on for a couple of hours less, which is still very good. Especially considering that there is fast charging: 10 minutes of charging is enough for 4 hours of music.

What else pleases the quality of the microphones: you hear the interlocutor well, the interlocutor hears you well.

Headphones are controlled by touch: double-click Play / Pause or accept / end a call. Long touch, switch between noise reduction and transparency modes.

But most importantly, how do they sound? It’s interesting here. The sound is atypical for TWS headphones, in which the bass is usually raised, like on Sony. Here, on the contrary, the bass does not protrude. Because of what the vocals are perfectly audible and in general the entire middle and top are very detailed. In general, the sound is very voluminous and it is a cut above any Apple headphones, and even more so any inexpensive TWS. Add here a convenient compact case and in general, the headphones are fire.

Excellent sound, battery life, there is a noise reduction mode, sound transmission, a compact case and a nice design of the headphones themselves. And also another intriguing technology, but we will talk about it at the end of the video. In the meantime, we continue about codecs

By the way, an important point when you listen to music via Bluetooth delays are inevitable. Because before you encode something in the Bluetooth codec, you must first decode the file that you are currently listening to.

It’s clear about SBC and AAC. both codecs can sound great if they are paired with the right equipment, or vice versa they sound bad with the wrong one. But is there a codec that will always sound good? Yes, there is such a codec and it is aptX.

aptX is an easy-to-compute codec without any psychoacoustics. It uses Adaptive Differential Pulse Code Modulation (ADPCM).

We will not go into details of what it is. But if in a simple way, it also uses quantization. rounding the signal values.

The aptX codec is owned by Qualcomm, but contrary to popular belief, Qualcomm did not invent it. And he appeared back in 1988, 14 years before the advent of Bluetooth.

In general, the technology is old, and the codec itself cannot be called the most intelligent, high-quality and efficient. Then why is aptX considered a good codec? There are several reasons for this.

First, aptX has several flavors that do their job well.

Plain aptX is great for the undemanding listener. At a similar bitrate, it will sound something like SBC. But aptX supports a bitrate higher than SBC, which means that with a good signal, it will sound better.

aptX HD with improved encoding profile and even higher bitrate.

It will already suit the more picky listener. According to SoundGuys tests, this codec is capable of outputting close to CD quality, which means that the codec is suitable for lovers of lossless music.

There is aptX Low Latency, with reduced latency for gamers, and aptX Adaptive with dynamically changing bitrate for a more stable connection.

But most importantly, aptX uses hard-coded profiles that neither the smartphone or player manufacturer, nor the headphone manufacturer can change. So, you will always know in advance what sound quality you will receive without surprises.

But to get all these cool flavors, aptX will have to pay a lot. After all, each flavor of aptX must be separately licensed from Qualcomm. Plus, you will need to buy more chips to support the coolest features.

TrueWireless Stereo type, which allows you to send two independent signals to both headphones.

But HUAWEI headphones can do this due to their technologies, so they often cost less and hold the battery better. The Power of Vertical Integration.

Well, without all the additional goodies aptX codec is not bad, but again, in all respects, not outstanding. However, you can listen to the difference in the sound of SBC, aptX and aptx HD right in your browser. Thanks to this wonderful person from Habr.

Pay special attention to the equalizer, how the SBC brazenly cuts off all frequencies after 20 kHz. The picture is clickable and leads to the player from the article.

And here we are slowly approaching outstanding codecs for connoisseurs of the highest quality sound. Of course, we are talking about LDAC.

This is the so-called Hi-Res codec from Sony and its main distinguishing feature is support for high bit rates up to 990 kbps and sampling rates up to 96 kHz

The codec is very common, since the LDAC encoder (libldac) is included in the standard distribution of Android, starting from the 8th version of the OS. And of course it is supported by Sony headphones.

The codec is capable of lossless CD quality, unlike aptX HD, which is still close to CD quality, but not quite. All this is confirmed by SoundGuys tests.

  • Marketing. It is promoted as a codec for Hi-Res audio, hence the support for 96 kHz sampling rate. But of course, no wireless codec can even come close to real Hi-Res.
  • Connection quality. It’s very weak. If you listen at the maximum quality of 990 kbps, then you should move away from the phone, cover it with your hand or just put it in your back. small stutters are almost guaranteed to start, which immediately spoils the buzz from listening to high-quality sound.

Plus there is a third drawback. At a low bitrate, which is as much as 330 kbps for this codec, LDAC loses in quality to both SBC and AAC and aptX, and the situation is aggravated by the fact that many smartphones turn on this quality by default.

What quality your smartphone exhibits can be viewed in the developer settings.

HWA LHDC. Low Latency High-Definition Audio Codec

But do not rush to get upset if the main audiophile codec disappointed you. After all, there is an even more audiophile codec that is devoid of the disadvantages of LDAC.

The name of this codec is LHDC or HWA, it is called differently.

So here is LHDC, which literally means high-definition codec with low latency. It was developed by the Hi-Res Wireless Audio Alliance and Savitech. And HUAWEI promotes the codec to the masses. It first appeared in the HUAWEI Mate 10 smartphone. And now it is supported in all new HUAWEI smartphones and in a bunch of Xiaomi smartphones:

  • Huawei P30
  • Huawei P20 Pro
  • Huawei P20
  • Huawei P20 Lite
  • Huawei Mate 10 pro
  • Huawei Mate 10
  • Huawei Mate RS
  • Xiaomi Mi 9 Pro 5G
  • Xiaomi Mi Note 10 Pro
  • Xiaomi Mi Note 10
  • Xiaomi Mi 8 Transparent Edition
  • Xiaomi Mi 8 Pro
  • Pocophone F1
  • Xiaomi Mi 8 SE
  • Xiaomi Mi 8 Lite
  • Xiaomi Mi Max 3
  • Xiaomi Mi Mix 3
  • Redmi K20
  • Xiaomi Mi 9T
  • Redmi K20 Pro
  • Xiaomi Mi 9T Pro
  • Xiaomi Mi 9 SE
  • Xiaomi CC9
  • Xiaomi Mi 9 Lite
  • Redmi K30
  • Redmi K30 5G

But in the future, its support may appear in general in all smartphones, because it is supported by Android 10 and is part of AOSP.

So, LHDC can be said to be a pumped version of LDAC. Because it takes all the advantages of LDAC, namely, high bitrate, up to 900 kbps and sampling rate up to 96 kHz.

But at the same time, it adds two versions of the low-latency codec, with the following names:

LHDC Low Delay = LDHC-LL or LARC

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And solves the main problem of LDAC. poor connection reliability.

In general, LHDC is still the number one contender for the title of the ideal codec for audiophiles. But in order to be sure of this, additional detailed testing is needed. While there is little information on the network about the codec.

Hence the reasonable question, I have headphones from HUAWEI here and I’m talking about the codec from HUAWEI. Is it in these headphones??

Um… no. This is the base model, in which special attention was paid to optimization.

But the most interesting and intriguing nuance is that these headphones support the new version of Bluetooth 5.2, which added support for the new codec that replaced the SBC. The codec is called LC3 and it should revolutionize the world of wireless audio just like the MP3 format did.

To give you an idea, at half the bitrate of SBC, the new codec sounds almost indistinguishable from uncompressed audio.

This is really a big breakthrough. But, despite the fact that LC3 is an integral part of Bluetooth 5.2 and all devices with the new Bluetooth must support the new codec, there is not a single smartphone with Bluetooth 5.2 yet. And these headphones also do not yet support either the new codec or the new Bluetooth 5.2 chips, which in themselves are a separate big conversation. In the future, support may be added, but we do not know for sure.

Therefore, we will talk about LC3 and Bluetooth 5.2 in a separate large material.

We did not talk about all codecs, but only about the most popular ones. For example, we did not mention the Samsung Scalable Codec, which has the main feature of connection stability, and this is essentially a competitor to aptX Adaptive. They did not mention the UAT codec with a crazy bitrate of 1.2 Mbps, which only works through the Hiby Music app.

We talked only about the most popular codecs, otherwise the conversation would be endless. Since there is a lot of information, for your convenience, we have compiled a comparison table to make it easier for you to navigate.

And if you liked the HUAWEI FreeBuds 4i headphones, dive on the link. As usual, gifts and special offers from HUAWEI are waiting for you there.

Once you’re in the developer menu, scroll down to “Bluetooth Audio Codec” and select it. Select the required codec. LDAC, apt, aptX, AAC, SBC.

  • go to “Settings;
  • select the “About phone” tab;
  • we find in the menu the item “MIUI Version”, which we press 7 times in a row.
  • go to “Settings” again;
  • click on “Advanced settings”;
  • we stop at the item “For developers”;

Xvid is a universal codec that is supported on most devices. The quality will be good, without lags. The video size is relatively small (at FPS. 30, 84000 kbps). However, if you have a powerful new graphics card from Nvidia, AMD or Intel built into your PC, the H264 codec is ideal.

This is the standard audio encoding technology used by BLUETOOTH devices. All BLUETOOTH devices support SBC. This acronym stands for Advanced Audio Coding.

Open devices and printers in control panel, find Bluetooth headset, open properties. Services tab, uncheck “wireless phone service”. When pairing with any device, try disabling various special effects and sound enhancers in the headphone app.

In developer options, go to “Network” and click on “Bluetooth audio codec”. Here you will have different audio codecs to choose from. Now you can switch from your existing codec to AAC, aptX or whatever. Experiment with them to get the best sound.

The golden mean. up to 200 Budget wireless. up to 100 Noise-canceling headphones TV headphones That is, any of the Android smartphones with Android 8.0 support LDAC by default:

You can enable or disable AAC (Advanced Audio Coding) or LDAC audio codecs.

  • Select [Setup]. [Bluetooth Settings] from the main menu.
  • Select [Bluetooth Codec. AAC] or [Bluetooth Codec. LDAC].
  • Select [On] or [Off]. On: AAC and/or LDAC audio is available if the BLUETOOTH device supports AAC or LDAC.

Go to the menu Settings Sounds Sound effects Sound amplifier Mi Sound (enable) and in this window select the appropriate headphones in the menu. Sound quality should improve.

  • go to “Settings;
  • select the “About phone” tab;
  • we find in the menu the item “MIUI Version”, which we press 7 times in a row.
  • go to “Settings” again;
  • click on “Advanced settings”;
  • we stop at the item “For developers”;

How to change Bluetooth codec for wireless headphones on Xiaomi (Redmi)

To transmit sound via Bluetooth, Xiaomi (Redmi) phones use a set of codecs, each of which differs from each other in transmission quality and connection stability, but how to change the Bluetooth codec on Xiaomi?

Historically, different codecs have been developed by different companies and at different times based on different technical capabilities of wireless headphones.

Therefore, today it’s hard to immediately figure out which one to choose on Xiaomi so that the headphones sound at the maximum potential they have.

At the beginning of the article, I will briefly show what codecs Xiaomi has and how they differ, and then I will show you how to choose them.

  • SBC is the simplest, which, when properly configured by headphone manufacturers, provides sufficient sound quality;
  • AAC is an advanced codec that provides good quality, provided that the gadget does not support aptX;
  • aptX, aptX HD, aptX LL. a set developed by Qualcomm, based on their own developments. When comparing many headphones in apt X and AAC mode, apt X wins in quality, but only when working on Android smartphones, which include Xiaomi. Headphones with AAC codec paired with iPhone will sound better, this is a feature of the implementation of the AAC codec on Android.
  • LDAC is the most advanced and developed by Sony. If it is supported by headphones, please use it, it will give the best result.
  • LHDC is the latest development, which appeared about a year ago, the developers promise the best sound quality. The problem is that there are no wireless headphones with its support on the market yet, so it’s too early to say anything about quality. Perhaps this is a new leader, but the opposite is also possible. time will tell.

We figured out the codecs, but I will add that each of them supports several data rates, which directly affects the sound quality. The higher the bitrate (data transfer rate), the higher the quality, but the stability of the connection deteriorates.

If you notice that the sound is sometimes interrupted or stutters, it is worth choosing a lower bitrate in the codec settings, this may help to get better stability.

The selection algorithm on Xiaomi is as follows: SBC. AAC. aptX. aptX HD. LDAC. LHDC.

On the left is the simplest codec, on the right is the most effective, you need to choose the one that your headphones support. If they support SBC and AAC, choose AAC. If you know how to work with SBC, AAC and aptX. choose aptX.

Usually, Xiaomi automatically selects the best option supported by the headphones, but sometimes manual intervention is required.

How to switch Bluetooth codec on Xiaomi

First of all, you need to unlock the developer mode, to do this, enter the settings, find the “About phone” menu. Find the line “MIUI version” and click on it 8 times in a row. Return to the general settings, find the line “Advanced settings”. Select the line “For developers”. Scroll through the long list until you reach the Bluetooth settings. For example, I connected headphones that support aptX. Look at the Qualcomm aptX Bluetooth audio codec option. By clicking on it, you will see a wide range of codecs, but if you select one that the headphones do not support, the sound will disappear. So before changing, look at the instructions for the headphones.

Note: Manual setting changes are reset each time the Bluetooth device is disconnected.

SBC works on almost all budget devices without much degradation in quality. The AAC codec is the official codec for iOS where it works most effectively. The peculiarity of AAC lies in its opposite to SBC: it is demanding on power and consumes a large amount of phone charge during operation.

  • We have both smartphones (devices) side by side at a distance of no more than 10 meters.
  • In the “Settings” menu. “Bluetooth” activate the function of the same name.
  • If the Xiaomi smartphone did not find the connected device, click the “Update” button below.
  • Select the required device from the drop-down list.

Open devices and printers in control panel, find Bluetooth headset, open properties. Services tab, uncheck “wireless phone service”. When pairing with any device, try disabling various special effects and sound enhancers in the headphone app.

как изменить аудиокодек на AAC на Xiaomi

In developer options, go to “Network” and click on “Bluetooth audio codec”. Here you will have different audio codecs to choose from. Now you can switch from your existing codec to AAC, aptX or whatever. Experiment with them to get the best sound.

Xvid is a universal codec that is supported on most devices. The quality will be good, without lags. The video size is relatively small (at FPS. 30, 84000 kbps). However, if you have a powerful new graphics card from Nvidia, AMD or Intel built into your PC, the H264 codec is ideal.

aac file on an iPhone with Airpods (these devices work great with the AAC codec), the smartphone still decodes the original AAC file first and then re-encodes it to the AAC codec. However, the sound quality may be slightly reduced.

On an Android phone, go to Settings and select About Phone. We find the “Build Number”, quickly tap on it several times. After the seventh tap, the system will report that you have become a developer.

In developer options, go to “Network” and click on “Bluetooth audio codec”. Here you will have different audio codecs to choose from. Now you can switch from your existing codec to AAC, aptX or whatever. Experiment with them to get the best sound.

SBC works on almost all budget devices without much degradation in quality. The AAC codec is the official codec for iOS where it works most effectively. The peculiarity of AAC lies in its opposite to SBC: it is demanding on power and consumes a large amount of phone charge during operation.

To enable AAC and any other codec, you need to activate the “Developer Menu”. Select the desired codec. LDAC, aptX, aptX HD, AAC, SBC. Main codecs for Bluetooth audio transmission: SBC, AAC, aptX, aptX Low Latency, aptX HD, LDAC.

  • go to “Settings;
  • select the “About phone” tab;
  • we find in the menu the item “MIUI Version”, which we press 7 times in a row.
  • go to “Settings” again;
  • click on “Advanced settings”;
  • we stop at the item “For developers”;

Simply put, aptX is a codec that, when paired with Bluetooth, is able to guarantee wireless transmission of lossless audio. Keep in mind that both paired devices must support aptX. For example, both a smartphone and a headset or speaker.

Find the “Audio codec” column, which displays the name of the codec or filter being used. The second way. Codec information can be obtained using VirtualDub. From the application’s main menu, select File and then Open video file.

Simply put, aptX is a codec that, when paired with Bluetooth, is able to guarantee wireless transmission of lossless audio. Keep in mind that both paired devices must support aptX. For example, both a smartphone and a headset or speaker.

Once you’re in the developer menu, scroll down to “Bluetooth Audio Codec” and select it. Select the required codec. LDAC, apt, aptX, AAC, SBC.

You can enable or disable AAC (Advanced Audio Coding) or LDAC audio codecs.

  • Select [Setup]. [Bluetooth Settings] from the main menu.
  • Select [Bluetooth Codec. AAC] or [Bluetooth Codec. LDAC].
  • Select [On] or [Off]. On: AAC and/or LDAC audio is available if the BLUETOOTH device supports AAC or LDAC.

On an Android phone, go to Settings and select About Phone. We find the “Build Number”, quickly tap on it several times. After the seventh tap, the system will report that you have become a developer. Go to “Developer Options” and look for the item “Bluetooth HCI Tracking Log”, turn it on.

We, in turn, want to sum up our top worthy, in our opinion, models: Good and inexpensive sound card. Asus Xonar U7 MKII; Best External. Creative Sound BlasterX G6; Premium Internal. Creative Sound Blaster ZxR.

Click the Start All Programs button and select Windows Media Player (Start All Programs Windows Media Player). Next, you need to get to the main menu, to do this, press the ALT key, and in the menu that appears, select Help About the program (Help About Windows Media Player).

Information about the video codec used can be found on the right side of the program interface, in the Video section. There you can see that the x264 codec is used for the video. You need to look for information about audio at the bottom there in the Audio section, PCM Audio is specified as the codec.

The quality will be good, without lags. The video size is relatively small (at FPS. 30, 84000 kbps). However, if you have a powerful new graphics card from Nvidia, AMD or Intel built into your PC, the H264 codec is ideal. For record weight, choose more standard codecs: Motion JPEG or MPEG-1.

The aptX codec determines how data will be transferred from the device to the headphones. The better the codec, the better the quality of the transmitted sound and the lower the delay, while the AptX codec is considered the best in these parameters and allows you to transmit sound with a quality comparable to playing CDs. This quality is achieved due to the ability of the codec to compress the signal and transmit more data up to 352 Kbps.

AptX HD. this is an improved version of the classic aptX, with better sound transmission. Both codecs are based on ADPCM (Adaptive Differential Pulse Code Modulation) technology, however the HD version has a higher bit rate. 576 kbps For comparison, the most common AAC and SBC codecs have bit rates of 250 and 328 kbps. respectively, the bitrate of these codecs is two times lower than that of AptX.

AptX Low Latency. is a Bluetooth codec that boasts the lowest audio latency available today. We are talking about 30-40 ms. this indicator means that the delay is practically absent and will definitely not be noticeable to the human ear. This codec is perfect for watching videos, as well as for fans of dynamic games.

AptX Adaptive. one of the latest developments, which incorporates the best from previous versions. This codec received sound quality close to AptX HD, and the delay time is almost comparable to AptX Low Latency. AptX Adaptive is considered the most promising of the line and may soon replace other versions of the codec.

How to activate AptX and which Xiaomi smartphones support it

AptX codecs were developed by the American company Qualcomm, which is known worldwide for the production of processors for smartphones. snapdragon. Initially, it was the processors of this series that had support for AptX technology, but over time it migrated to MediaTek processors.

Xiaomi has taken care of users, so the smartphone will automatically turn on the required codec when connected to headphones. However, the developers still left the ability to automatically configure the codec. In the same way, you can check if the smartphone supports codecs. In order to check the support of the aptX codec, you need to:

  • Go to “Settings”, go to “advanced settings” open the item “For developers”, find the item “Audio codec for transmission via Bluetooth” and see the list of supported codecs.

aptX codec on Xiaomi (Redmi): what is it, how to enable

I suppose many of you use wireless Bluetooth headphones paired with a Xiaomi smartphone, but did you know that additional hardware and software solutions called codecs work to transmit sound within this protocol.?

There are quite a lot of codecs for Bluetooth on Xiaomi today:

And I have listed only the most common, there are more exotic solutions.

And here you may have a reasonable question: what do codecs do and why are there so many of them?

Codec. encodes and decodes the audio signal using a special chip designed for this task.

Today we will talk about the aptX family of codecs.

Which aptX codecs support Xiaomi smartphones?

Xiaomi phones support the full set of codecs of the aptX family:

  • aptX. basic version;
  • aptX HD is a codec variant with the highest quality of music and sound transmission;
  • aptX LL. option with the lowest possible audio transmission delay;
  • aptX Adaptive is an adaptive method that, depending on the situation, independently decides whether to increase the quality of the transmitted sound or reduce the delay.

In general, aptX is developed by Qualcomm, which designs and manufactures Snapdragon processors.

The design goal was to create a method for transferring music using Bluetooth with the lowest possible loss in quality.

Unfortunately, Bluetooth is not capable of transmitting an audio stream without additional compression, there is not enough bandwidth. But no one is in a hurry to replace Bluetooth with Wi-Fi due to the extremely economical operation of the first, and, conversely, the gluttony of the second.

In other words, all manufacturers have decided to go for some loss in sound quality, but not a significant reduction in the autonomy of gadgets.

Well, since the audio stream is being encoded and compressed, it is necessary to develop a method that would efficiently compress the digital stream, and at the same time work fast enough to be able to use low-power chips that would not noticeably affect the autonomous operation of Bluetooth headphones and phones.

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Therefore, the choice is limited, if you need the maximum sound quality in wireless headphones. use aptX.

But there is a fly in the ointment here. in order to use aptX, headphone manufacturers have to use chips that are designed by Qualcomm, which means they have to pay for them and pay an additional license.

Not everyone goes for this, so many modern and expensive wireless headphones do not support aptX.

How to enable aptX on Xiaomi

A prerequisite for activating aptX on Xiaomi is the officially declared support for this codec by the headphone model.

If this codec is not in the description of the headphones, when Xiaomi is forced to switch to aptX mode, the sound from the headphones will simply disappear.

But sometimes a software failure occurs, or the headphone firmware contains errors, and it is necessary to force the operation to switch to the mode we need.

By the way, you can find out which mode is being used right now as follows: open the “Bluetooth” settings on Xiaomi. You will see the name of the gadget connected right now, next to which the codec used will be indicated in small text. If you need to forcibly change the operation of the headphones yourself, then the first thing you need to do is unlock the “For Developer” mode.

Enter the “About phone” menu. Find the line “MIUI Version” and click on it 8 times in a row, after which you will see an unlock message. Now find the “Advanced Settings” menu. Scroll down the list and you’ll see that a new “For Developers” menu has appeared. Very carefully, without clicking on those items that are not clear to you, scroll through the list to the “Networks” section. Inside it, you will find the line “Audio codec for transmission via Bluetooth”. Next to it is the current codec, but if you click on it, a list of all supported codecs by your Xiaomi model will appear. Choose the one you think should be used. If the sound is gone, it means that the headphones do not know how to use it, go back to the codec in which everything worked fine.

Please note that after disconnecting the headphones and reconnecting them, the codec will be automatically selected again.

Jiks Buds review: TWS headphones with AAC codec support

The Jiks Buds came to my review: in-ear headphones with a modern design in a matte metal case. A model with mics in each earcup and a dynamic driver inside that accurately captures detail and depth. Using Bluetooth 5.0 technology, we get an excellent connection between a smartphone and wireless headphones. By the way, they charge quickly enough in the case. The price for such a set of “buns” is average (in terms of about 44), which leaves a good good impression of the capabilities of the headphones, so let’s delve into the review.

Characteristics and equipment

  • Headphone dimensions: 201725 mm; weight: 4 grams;
  • Case dimensions: 555525 mm; case weight: 58 grams;
  • Audio decoding support: AAC, SBC;
  • Sensors: touch panel;
  • Data transmission: Bluetooth 5.0;
  • Headphone battery: 35 mAh;
  • Case battery: 350 mAh (5 full headphone charges);
  • Autonomy: up to 4 hours, when using the case. up to 20 hours;
  • Charging: USB Type C, Qi wireless standard.

The headphones come in a modest package: 2 Jiks Buds, a case, a charging cable, paper instructions in Ukrainian.

Design and build quality

Charging case for Jiks Buds

Overall, Jiks has a simple and elegant design. As for the charging case, it is made in the form of a rectangle rounded at the corners. Slightly flattened, very compact and light (only 55 g), made of brushed aluminum alloy. I have it in navy blue, but it also comes in black. There is no logo, but inside there is an amusing inscription-slogan “My device. my life”.

There is a long slot in the center of the front for opening the case, which is complemented by a built-in magnet for easy opening and closing with one hand. The headphone recesses are also magnetized, have L / R designations and automatic charging start. Under the notch are 4 blue LEDs that indicate the battery status of the case.

The bottom of the charging case is flat for more stability and is made of plastic to allow for wireless charging (rare in this price range). There is also a USB Type-C charging port located on the side panel, which is convenient.

Let’s move on to the Jiks Buds wireless headphones themselves. They have a compact plug-in design with a brushed metal surface, matching the color of the case. The main part is plastic, so the case turned out to be light (about 4 g), so that the earbuds can be comfortably held in the ear while moving. There are compensation holes on the case that balance the internal and external air pressure and help ventilation.

The letters “L” and “R” are printed on the inside of the headphone case to distinguish between left and right ear. The outer side of the headphones has a microphone hole for good and clear sound reception during a call, LEDs for timing display and a touch control button. There is a noise-cancelling hole next to the magnetic charging contact that interacts with the microphone to accurately distinguish between human voice and extraneous noise.

Touch control panel

To control the Jiks Buds, there is a touch pad on the top of the earphone with high touch sensitivity. Control consists of answer / reject a call, play / pause music, adjust the volume, switch the track, call the voice assistant.

  • Music pause/play. double tap
  • Answer/end call. single tap
  • Call Siri or Google Assistant. triple tap any earbud
  • Skip to the next track. hold down the button on the right earbud for 2 seconds.
  • Return to the previous track. hold down the button of the left earphone for 2 seconds.
  • Reject a call. touch and hold the earpiece for 2 seconds.
  • Volume up. while listening, touch the touch area of ​​the right earbud
  • Turn down the volume. while listening, touch the touch area of ​​the left earbud

How to connect Jiks Buds to your smartphone

Jiks Buds provides strong compatibility with iOS and Android devices. The earbuds use Bluetooth 5.0 technology for faster transmission, lower latency and more stable connection. With sound transmission up to 10 meters, even with thin walls between you and your smartphone, you can get high sound quality.

Pairing the Jiks Buds with a smartphone is pretty straightforward. You need to open the charging case and they will automatically turn on and enter the pairing state. After pairing with each other, one of the earbuds will flash red and blue alternately. Immediately after that, open the Bluetooth interface of the smart phone, the device name is “M20”. Click it and pairing will be completed successfully. Pairing is done manually once, after which it happens automatically if the Bluetooth of the smartphone is turned on. Just take the earbuds out of the case and you can use.

Sound Quality Jiks Buds

The Jiks Buds have dynamic drivers that deliver smooth, natural sound to pop, rock and other rhythmic music. They show good detail and generally good performance throughout the range. I also note an excellent sound stage. Another good news is that this model supports the AAC audio codec, which provides high-definition sound for different musical styles. Pretty good for this price range.

Digital noise reduction technology

One of the strengths of the Jiks Buds is the noise-canceling technology, which is responsible for 2 microphones on each earbud, one at the top and one on the side. On the top is a noise-canceling hole that picks up environmental noise. Uses an internal digital signal processing algorithm to reduce background noise when making calls. The sound during a call here is good, as for me. The voice is not too muffled and there is no hiss, but I would not say that there is no noise at all.

Battery and charging time

The Jiks Buds Charging Case is equipped with a built-in 350mAh lithium polymer battery and provides an additional 20 hours of continuous playback. When you put the earbuds into the charging case, they will automatically enter the charging state. The storage case itself charges for 2 hours, then the earbuds can be charged 4-5 times. Each earbud has a 35mAh battery that can be used for 4 hours. There is a charge indication on the case body: 1 indicator. 25% charge, 2 indicators. 50% charge, 3 indicators. 75% charge, 4 indicators. 100%. The case charges through the Type-C port on the side of the case. It also supports wireless charging.

Jiks Buds are good wireless headphones that combine high sound quality for dynamic drivers with an interesting design. Support for AAC and SBC codecs will satisfy most lovers of listening to music from a smartphone. Headphones in the price range up to 45 and they will give you the sound quality you need from wireless headphones. For the rest, perhaps, more expensive options are needed.

aptX Adaptive and aptX Low Latency

AptX Adaptive is the latest codec under the aptX brand. According to Qualcomm, this codec will replace aptX HB and aptX LL in the future. In terms of sound quality, it stands between aptX and aptX HD. And in terms of delay time, it approaches aptX LL. Such a versatile soldier.

An important difference between this codec and the rest of the aptX line is that the priority is given to the quality of the connection, and not to a large bitrate. What’s the point of 990 kB/s (hello, LDAC) if the connection is constantly falling off during such a transfer?

  • Bit: 16 and 24 bits
  • Sample rate: 44.1 and 48 kHz
  • Bitrate: 279. 420 kB/s (dynamic, adaptive)
  • Latency: 50-80ms

As the name implies, aptX Adaptive has a variable bitrate (279. 420 kB / s), which automatically adapts to the surrounding conditions and the quality of the files being played. Not very clear? Then a little more.

  • Bitrate. As you can see, it is lower than aptX (352 kB/s) and aptX HD (576 kB/s). However, according to the manufacturer, Adaptive uses more efficient compression algorithms that allow you to get good sound quality at a lower bitrate. This can only be verified by experience. Looking forward to widespread adoption.
  • Variable bitrate. It can be noted that for LDAC, for example, the bitrate is also not constant. But there it can be set (automatically or manually) only in three versions: 330 kB/s, 660 kB/s and 990 kB/s. And aptX Adaptive has no change thresholds, the bitrate can change by 10 kB / s, and by hundreds. within the declared range. That is, fine tuning.
  • Why do you need a variable bitrate at all? To improve the quality of communication depending on the quality of the material and the surrounding conditions. The codec calculates many parameters on the fly and instantly adjusts the bitrate according to them.
  • The quality of the source material. If the initial bitrate of a file is low, then it makes no sense to pack it into a higher one. So, for example, it happens when a simple aptX transfers a file with a bitrate of 256 kB / s, encoding it at 352 kB / s. That is, there is an extra load on the bandwidth of the wireless connection: it was possible to take 256 kB / s, but 352 kB / s is occupied.
  • environmental conditions. This codec also adapts to the congestion of the air. It uses the phone to monitor the air (in the frequency band used by Bluetooth and other wireless protocols) and adjusts the bitrate accordingly. That is, if there is no interference, and the file is of good quality, then the maximum bandwidth is allocated. 420 kB / s. And if everything around is clogged, the bitrate is reduced automatically to ensure high-quality communication.
  • delays. Adaptive has good performance: 50-80 ms. This is worse than aptX Low Latency (30-40 ms), but in 95% of cases this difference will be indistinguishable by ear. And this figure is much lower than the average 150-200 ms for other codecs.

AptX Low Latency is a Bluetooth codec with the lowest audio delay today. It is about 30-40 ms and is practically not noticeable. Accordingly, this codec is relevant for watching videos and / or games using wireless headphones.

Comparison of aptX Adaptive, LDAC, AAC and SBC

AptX Adaptive and Low Latency are the newest and most promising codecs from Qualcomm. Adaptive, apparently, will soon be the main one in the line, replacing older versions. The manufacturer promises backward compatibility. But, of course, the use of specific processors from Qualcomm is necessary for the operation of their codecs: both new and old.

These codecs precede the general top because, as they say, they are the future. However, they are still nowhere near as widespread (and tested) as the older codecs of the aptX family.

Sennheiser IE 80S BT headphones with aptX Low Latency support

AptX Adaptive

  • Reliable connection thanks to adaptive bitrate.
  • Supports 16bit/44. kHz and 24 bit/48 kHz.
  • Good sound quality.
  • High energy efficiency.
  • Small audio delays (50-80ms).
  • Low prevalence.
  • Requires one of the new Qualcomm processors.
  • Sound quality is still lower than LDAC.

AptX Low Latency

  • Lowest audio delays.
  • Good signal transmission parameters and sound quality (like aptX).
  • Fairly reliable connection.

aptX, aptX Low Latency, AAC and SBC bitrate

  • Not the best sound quality.
  • Communication reliability decreases in busy air.
  • Not very common. And will retire after the active implementation of aptX Adaptive.

TOP 5: Bluetooth audio codecs aptX (HD), LDAC, AAC and SBC

There are 5 main Bluetooth audio codecs that transmit sound from source to headphones (or speakers) via Bluetooth: SBC, AAC, aptX, aptX HD and LDAC. As wireless connectivity becomes more and more popular, it’s a good idea to understand what Bluetooth codecs are and how they work.

Best wireless earbuds 2021:

It is worth noting immediately 2 points:

  • Sound over Bluetooth is still noticeably worse than wired in all quality parameters;
  • Wireless sound with high-quality codecs already at this stage is able to satisfy the needs of most users.

We will no longer focus on these axioms. In general, they are clear. And it is unlikely that many people with listening and comparison experience will argue with them.

How to choose, change, find out the Bluetooth codec on an Android phone?

To change the Bluetooth codec to any of those supported on your phone, you need to activate the “Developer Menu”.

The Developer Menu can be activated like this:

After, in the developer menu, you need to find the Audio codec for transmission via Bluetooth and select the desired codec:

Select the desired codec LDAC, aptX, aptX HD, AAC, SBC.

Which is better: listen to music over a wire or via Bluetooth?

Below we will figure out which of the common Bluetooth codecs is better and whether it is worth listening to music wirelessly in general. Let’s start with whether it is worth listening to music over the air?

  • For the so-called “analytical” listening to music (in a quiet home environment), it is better to choose a wired connection.
  • But for noisy places, like transport or city streets, a Bluetooth connection is quite suitable: ambient noise hides and compensates for the flaws in the work of codecs. Bluetooth headphones are also a priority for young people who like to listen to music on the move.

Basic concepts of Bluetooth audio transmission

Bluetooth audio is now transmitted via the A2DP profile. This is a part of the stream specialized for broadcasting an audio signal.

Theoretically, this profile has no restrictions on the occupied data bandwidth. But there is a limitation for the entire format: no more than 1 Mbps. Accordingly, uncompressed audio even in CD format (there is a bit rate of about 1.4 Mbps) cannot be transmitted via Bluetooth.

Why all these restrictions? Energy efficiency. Otherwise, it would not be possible to listen to wireless headphones for 20 hours. And if there was, then the batteries would noticeably bend their heads to the ground.

Wireless headphones are first and foremost about convenience.

The Bluetooth signal is packed at the source and unpacked at the end device (headphones, speakers, etc.). Accordingly, both devices must support the codec over which data is transmitted. Or will the younger version be used.

If your phone supports, for example, LDAC (and it has been added to Android since version 8 at the OS level), and the headphones are only SBC, then you will not feel the delights of high resolution, the transfer will go through SBC.

What is bitrate, I think everyone knows. This is the number of bits used to transfer data per second. The higher it is, the better, obviously. But the more resources are required, in particular, power consumption, disk space, etc.

Compression has long been used to optimize resources, both lossy and lossless. Lossless compression uses algorithms to reduce the bitrate and file size without changing the original. That is, from lossless you can restore an exact copy of the original uncompressed file.

Lossless processing allows you to reduce the bitrate by a maximum of 2 times. Or so. For example, for a lossless compressed CD-quality file (1411 kb/s), we will see values ​​of 770-900 kb/s. Anything below is lossy compression.

  • When the bitrate and/or file size needs to be further reduced, it is compressed by discarding non-essential bits of information. That is, the selected codec, using its algorithms, decides in which frequency range there is no data (or they can be neglected), and discards them. Uncompressed original cannot be restored from received file.
  • Algorithms for codecs are different: some exclude only high-frequency sounds, some are based on psychoacoustics. For most, the difference between a good lossy track and its lossless version is negligible or non-existent.
  • In addition to dropping in lossy compression, there is the addition of overlapping blocks of information. This part of the algorithm aims to equalize the signal and correct quantization errors.
  • The sampling rate indicates how many discrete segments an analog signal is divided into for digital recording. The larger it is, the closer the figure is to the original. Measured in hertz. This concept is inextricably linked with the frequency range.
  • A person hears sounds from 20 Hz to 20 kHz. It has been proven that in order to quantize (digitize) a lossless audio signal, the sampling frequency must be more than 2 times the frequency range of the original audio signal. Accordingly, CD-quality at 44.1 kHz is quite enough. the creators of the format were repelled from this law.
  • The bit depth determines how many bits are needed to quantize each of the segments mentioned above. The bigger, the better. It is logical that the audio format (or codec) is considered the better, the higher its bit depth and sampling rate. 16-bit and 44.1 kHz for CD versus 24-bit and 88.2 (or more) kHz for Hi-Res audio.
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The background noise level determines when the useful signal becomes indistinguishable from the noise of the codec’s compression algorithm, in this case. The lower this level, the wider the dynamic range of the final signal, the quieter sounds we can distinguish.

On the charts, it is best to navigate from the highest peak, it can drown out quieter sounds. Not only the level of the peaks is important, but also how even (dense) they are. Standard levels of background noise are indicated on the graphs by a dotted line for 16-bit quality and the upper limit of the red zone for 24-bit.

All codecs try to save bandwidth. In addition to all other tricks, quantization noise is carried out in the RF range above 20 kHz whenever possible. A person does not hear these sounds, so the algorithm is justified.

The indicator of the level of the received signal acts as an indicator of the quality of communication. It is measured in dBm (decibel-milliwatt). The vertical axis shows the lost seconds when playing the sound.

  • Up to.60 dBm. the level sufficient for real-time data transmission;
  • Artifacts and interruptions can start at.70 dBm;
  • Below.80 dBm. perceptible delays and packet losses;

Connection quality for different codecs

If the loss of seconds (packets) starts at.80 dBm, then with an average distance (from to ear) from the source to the receiver (headphones), the connection will be stable, almost without interference. If earlier (-60.70), then the connection will be unstable: with breaks and stutters.

TOP 5 Bluetooth codecs which codec is better?

All Bluetooth codecs are lossy compression algorithms.

  • The signal is divided into several frequency bands (their number differs for different codecs) and quantized with a constant or different bit depth.
  • When compressing, some of the information is cut off, some is added.
  • Quantization errors and noise are moved beyond the boundaries of human hearing, if possible: to frequencies that are often absent after decompression.

AptX HD

AptX HD is the most optimal Bluetooth codec that allows you to transmit sound in a quality close to CD. By the combination of parameters, this codec gives the optimal ratio of sound quality and communication stability. It significantly loads the Bluetooth transmission band, but at the same time gives a very decent sound.

Qualcomm claims that this codec achieves sound close to Hi Res, but this is not confirmed by tests. But it sounds pretty good.

Bowers and Wilkins PX with aptX HD support

AptX HD almost covers the human audible range: the ceiling at 19 kHz. The result is quite good, because few people over the age of 25 hear anything above 18 kHz. Declared maximum sampling rate of 48 kHz. For encoding here, apparently, 40 kHz would be enough (192 = 38).

The maximum bitrate of aptX HD is 576 kbps. Accordingly, Hi Res sound with a bitrate of 4.5 Mbps is compressed in a ratio of 8:1, and CD quality is 2.5 times. When compressed, the signal is divided into 4 frequency bands and quantized with 24 variable bits.

It is logical to assume that the transmission of CD-quality sound will occur with not very large losses.

AptX HD is far from 24-bit audio in terms of background noise, especially in the high-frequency range. Accordingly, there is distortion and noise that can mask the quiet details of high resolution recordings. After all, they are designed for a greater dynamic range.

But almost over the entire range, the noise level corresponds to the parameters of CD-quality. Apparently, 16-bit recordings through aptX HD are quite comfortable to listen to, losses and distortions are small.

Packet loss for aptx HD starts at.70dBm and rises quite sharply right after that. The reliability of the connection is relatively low. Most likely, when listening to source from a short distance (in your ), there will be no problems with transmission. But minimal interference (head rotation, obstruction, other wireless networks) can very easily cause stuttering and music interruptions.

Considering that this codec occupies more than half of the Bluetooth bandwidth in terms of bitrate, the result is expected. Comfortable listening is, in principle, possible.

Reasons for the poor quality of the AAC codec on Android

There are two main reasons for the difference in AAC quality on Android and iOS:

Xiaomi Mi AirDots Pro and Apple Airpods support AAC codec

Andriod has Energy Aware Scheduling (EAS) algorithms. This system reprioritizes processes according to their energy intensity. That is, the choice for which task more processor power will be allocated (and the processor in smartphones performs a huge number of tasks at the same time) can vary.

If the system is configured to save battery power, like the Huawei P20 Pro, then when performing a complex task for the processor, priority will be given to optimizing power consumption. As shown above, AAC uses psychoacoustic algorithms when encoding, and this is a rather heavy load on the processor. Accordingly, this task will be performed with a lower bitrate and quality in general to optimize energy costs.

Sony WF-SP700N. fully wireless headphones with AAC support

If EAS had given the AAC encoding process a high priority, it would have squandered the battery a lot, although the quality would have improved. But the priority is to save the charge, the quality of EAS in this case is sacrificed.

The second main reason is different encoders, AAC encoding software. iOS uses Apple AAC, which is considered the highest quality available. And in Android, the default is Fraunhofer FDK AAC, it does its job a little worse.

Apple AAC, of ​​course, does not exist under Linux, so you will not be able to install it on an Android smartphone. And on the iPhone, as you know, it’s generally better not to install anything third-party.

Bowers and Wilkins PX with AAC support

In addition, in the Android software environment, many audio formats are supported at the hardware level, unlike iOS. Don’t forget about audio tunneling, which works with Android 4.4. This is the transfer of audio encoding / decoding to a dedicated part of the common chipset. DSP (digital signal processor). digital signal processor.

iPhones use more or less the same processors, while Android smartphones can have very different ones, hence the different operation of audio tunneling and the difference in the resulting AAC encoding, for example.

AAC background noise level

The background noise level shows the boundary, after which the noise from the codec compression algorithms (in the general case, from any reproducing equipment) becomes indistinguishable from the useful signal. music. The lower and more stable this level is over the entire frequency range, the quieter sounds we can hear (if they are on the recording).

It is best to navigate from the highest peak, it can drown out quieter sounds. Therefore, in these graphs, not only the level is important, but how even (dense) they are.

AAC background noise level (source. lossless file)

The graph clearly shows that the level of background noise when using AAC in Huawei P20 Pro and Galaxy Note 8 is significantly higher than in the iPhone 7. In the intervals between peaks (test signals), it can be seen that AAC filters out places where there is no sound information well.

This graph also shows that the algorithms used in AAC take psychoacoustics into account. The test sound is loudest at 1 kHz (this is where our hearing is most sensitive), and the noise around it is also the highest. It turns out that the AAC codec masks quieter sounds at the same frequency under louder ones: the louder the sound, the higher the background noise.

This is how our hearing works: the brain masks quiet sounds if there are louder ones on these. We perceive orchestral music as a whole canvas, and not as separate signals (although we separate the instruments). The same principle: it is difficult to hear something quiet over the noise of a vacuum cleaner, for example.

CD quality implies a background noise level of.96 dB. Of course, in the case of AAC, this quality is not achieved, although on the iPhone at 1 kHz we see noise of.91 dB, which is generally not bad. But on Android phones, the peaks are adjusted to.50 dB: the level when the background noise is clearly distinguishable.

AAC frequency range

AAC compresses lossy audio: extra frequencies are cut off, the signal is equalized (overlapping blocks of information are added), errors are corrected. Approximately on the same principle all lossy codecs work (codecs for lossy compression).

Losses are mainly expressed in the reduced frequency range: usually the upper limit of the RF. In addition, due to signal equalization, distortion can be added (and most often added), which can be in any region of the range.

Let’s see how AAC (source. lossless audio file) performs in comparison with SBC on some Android smartphones and iPhones:

Full frequency range using AAC and SBC codecs

Serious differences in the implementation of AAC on different smartphones are immediately visible. It is worth considering several points:

  • a person can theoretically hear sounds in the region of 20 Hz. 20 kHz;
  • most of the material in music is below 16-18 kHz;
  • with age, we perceive HF worse (up to 16-17 kHz on average after 30 years)

Consider the edge of the HF range larger:

As you can see, AAC on Huawei P20 Pro cuts off high frequencies very early: around 14 kHz. These frequencies are heard even by very elderly people, if there were no hearing problems. The Samsung Galaxy Note 8 (via AAC) limits the upper threshold to 17kHz. But the iPhone 7 does better: around 19kHz.

This scatter of results is especially interesting in comparison with the operation of the SBC codec on the same Android smartphones. The upper limits of the range for all test subjects are higher, albeit with greater distortion. But the main thing is that they are very similar: that is, the SBC codec works more or less the same on different phones.

What is AAC (Bluetooth Codec) comparison of AAC on iOS and Android

The AAC (Advanced Audio Coding) codec was created back in 1997 as a better than mp3 codec for audio compression. And in some ways it is really better, for example: higher sampling rates are available (up to 96 kHz) and the algorithm itself uses the psychoacoustic features of human hearing.

AAC is now the main audio codec for lossy compression in the Apple ecosystem. He is also the main one on YouTube and even Russian TV broadcasting. But we are interested in its wireless implementation. All iPhones and many Android devices can transfer music via Bluetooth by converting this codec.

Since the Bluetooth transmission parameters are not enough to broadcast lossless music, codecs are used: algorithms that divide the transmitted signal into parts and send it over the air to the headphones. And there, in turn, through the same codec, unpacking and digital-to-analog conversion of the signal into music takes place. I think all portable audio lovers know about these circuits.

How to enable AAC?

To enable AAC and any other codec you need to activate the “Developer Menu”.

The Developer Menu can be activated like this:

After, in the developer menu, you need to find the Audio codec for transmission via Bluetooth and select the desired codec:

Select the desired codec LDAC, aptX, aptX HD, AAC, SBC.

The main codecs for audio transmission over Bluetooth: SBC, AAC, aptX, aptX Low Latency, aptX HD, LDAC. In addition, another codec from Qualcomm was introduced relatively recently: aptX Adaptive, but devices with it are still only expected. Which of the codecs is better is a moot point. If we take only the bitrate, then AAC is far behind. However, its good implementation (on the iPhone) is not much different from aptX.

Comparing how AAC works on two major mobile operating systems is interesting because it’s the only codec other than the ancient SBC that’s used on both. Apple stubbornly refuses to pay Qualcomm for aptX license. Apparently, guided by the principle: if you don’t hear a difference, why pay more?

Top 10 AAC-Enabled Headphones

  • Audio-Technica ATH-M50xBT (311). full-size wireless closed headphones. Legendary Bluetooth M50 Bass Sound.
  • Beyerdynamic Aventho Wireless (560). on-ear wireless headphones. Great design signature Beyerdynamic sound.
  • Xiaomi Mi Collar Bluetooth Headset (59). wireless in-ear hybrid headphones with a neckband. Autonomy up to 8 hours, suitable for both sports and everyday use.
  • Sony WF-SP700N(202) are fully wireless sports vacuum headphones. Has IPX4 protection and active noise cancellation.
  • Sennheiser Momentum True Wireless (356) are fully wireless in-ear headphones. One of the best-sounding models in the segment Sennheiser signature design.
  • Bowers Wilkins PX (420). full-size wireless headphones with active noise cancellation. Stylish appearance and high-quality sound, great for electronic music.
  • Bang Olufsen Beoplay H9i (544). on-ear wireless headphones. Active noise cancellation, great sound and touch controls are complemented by high-quality voice transmission in headset mode.
  • Marshall Monitor Bluetooth (166). Full size wireless headphones. Signature Marshall look and feel, interesting powerful sound for energetic styles.
  • Sennheiser Momentum Over-Ear Wireless (M2 AEBT) (290). Full size wireless headphones. Loved by the beautiful design and powerful bass sound of Momentum in Bluetooth version.
  • Sony WH-1000XM3 (465). full-size wireless headphones with active noise cancellation. One of the best ANC options on the market Lots of high tech features from Sony.

AAC Features

Another interesting point is that even files already encoded in AAC change when transferred over the Bluetooth version of this codec. That is, they recode again. Before that, the test files were in uncompressed format.

Upper end of the frequency range. Source. AAC file

In general, the picture repeats itself. The decline in the iPhone comes much later and is getting closer to the upper limit of hearing, unlike Android phones.

From the graph of the background noise level, it is clearly seen that even on the iPhone, the AAC file is re-encoded when transmitted via Bluetooth AAC: about 15 dB of noise is added. The general trend has not changed: both with lossless and AAC files, when transmitted in the air through the codec of the same name, the iPhone looks better: re-encoding adds less distortion here.

As a result, we can say that AAC is a very interesting codec. Its quality cannot be judged simply by the level of background noise and frequency range, as is the case with other codecs. AAC in its algorithms takes into account psychoacoustics, auditory masking. quality cannot be measured only in numbers.

Airpods 2 support AAC naturally

Outcome

Considering all of the above, it becomes clear that a high-quality implementation of AAC (on the iPhone) gives a very good final result, which is hardly distinguishable by ear from high-quality codecs, for example, aptX. However, if encoding takes place at a lower bitrate, as on the tested Android smartphones, the quality suffers greatly.

The most important thing is the differences in the operation of AAC on different smartphones. The same SBC, for example, shows more stable results from model to model. Accordingly, if your phone is running Android, AAC is not necessarily better than SBC, as is often believed.

Apple Airpods paired with iPhone via AAC sound pretty good

On some models, SBC may perform better than AAC. And not only in numbers, but also by ear. Therefore, if you bought headphones with AAC support, but you don’t like the sound in conjunction with your phone, try switching to SBC, perhaps AAC is implemented worse in your model.

The implementation of AAC on the iPhone is better. the sound is very strong (for lossy compression) close to CD quality. In the Android environment, AAC works worse, most often at a lower bitrate, hence additional distortion and loss of compression. At the same time, the final result can vary greatly on different phones.

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