Version Bluetooth AVRCP 1.6. How to choose a Bluetooth device for listening to music

In my current review, I want to tell, about the technology of transmitting sound via Bluetooth wireless protocol. About what you need to know when choosing a wireless stereo headphones. And describe in detail the hero of our today's review - Bluetooth headphones Macaw T1000.

Part I. Choose a headset. We deal with Bluetooth technology

Bluetooth Profiles HSP, HFP and A2DP

1. HSP (Headset Profile). This profile is designed to work with mobile headsets and is sharpened to the basic voice: audio is allowed only in mono format and with a bit rate not higher than 64 Kb / c. Compared to this sound, even pushed MP3 seems to be divine pleasure for the ears.
2. HFP (HANDSFREE PROFILE). A slightly more advanced version of the HSP profile. Its appointment is monophonic headsets, so stereo is still not supported, but the sound quality is slightly higher. To listen to music, this profile is still not suitable.
3. A2DP (ADVANCED AUDIO DISTRIBUTION PROFILE). The most advanced profile at the moment. It is he who is responsible for connecting mobile devices with wireless columns and headphones. A2DP profile allows sound source to find a common language with wireless acoustics, And most importantly, it controls the compression of the audio to send the channel to the "blue-paper". It is impossible to avoid this procedure due to the low Bluetooth bandwidth, but the level of compression used to compress the algorithms and, ultimately, losses as sound can be markedly vary. Here, as they say, the nuances arise.
But the sound quality depends not only on the audio profile, but also the audio codec, with which the transmitted audio signal is shown.

SBC codec

The easiest audio codec. Sound processing according to SBC methods has a lot in common with a good all familiar MP3 compression, but priorities are built somewhat differently: the main task is not so much to minimize sound losses how much to simplify the calculations. Everything must be quick, simple and easy to do even for the most harvested mobile processor. As a result, the SBC costs the sound without unnecessary ceremonies - for example, frequencies above 14 kHz during conversion is simply cut off, with the result that the frequency range is noticeably narrows. It is not surprising that even with an equal bit rate with MP3 (and SBC allows a bitrate to 320 kb / c) audio in SBC encoding sounds noticeably worse.
As a result, when using a default encoder, Bluetooth worsens the sound of not only uncompressed audio, but also normal MP3 files - after all, in the process of wireless transport, they are first decoded, and then compress again, this time where is gross.

AAC codec (Advanced Audio Coding)

At the expense of more complex AAC algorithms really retains more musical information than mp3, and even more so SBC. It is not surprising that its inclusion in the set of codecs supported by the A2DP profile, significantly improves the sound of Bluetooth speakers and headphones. The main thing is to make sure that the AAC codec is supported by both "synevs" devices: and by what serves as a transmitter of the audio signal, and what works at its reception. If, from a pair of such devices, AAC encoding is able to understand only one - the A2DP profile automatically rolls back to the base codec. With quite obvious consequences for sound.

APTX codec. The most advanced audio codec is the best option for music love.

Even more advanced sound compression provides APTX codec, which actively promotes the CSR Bluetooth-audio market. The creators promote it as a means for wireless music transmission "in CD-quality".
In fact, this is not entirely so, although the algorithms underlying APTX, according to the principle of their work, really resemble lossless encoders that seal the audio stream without losing sound information. Among the advantages of APTX is the ability to Bluetooth-broadcast MP3 and AAC without additional processing, which means that without a worsening sound.
The APTX codec provides audio transmission with a bit rate to 352 Kb / s, does not cut up the upper register and spreads the frequency range to quite solid 10 Hz - 22 kHz, but the high complexity of the algorithms used requires from mobile processors of tripled computing power compared to the base SBC. That is why the support of APTX meets among the "blue-refine" devices quite rarely, most often in the premium segment of smartphones.
Determine the support of the APTX codec from the device

Now we know that to obtain high-quality sound, both devices, and source (transmitter) and the headset (receiver) must support A2DP profile and APTX codec.
If everything is simple with the headset, this information You can find on the product page in the store, on the manufacturer's website, or a box, then information about the support of the APTX codec smartphone or player provides not every manufacturer. In fact, check it easy enough. To do this, go to the site and try to find your device among those supported.
My Asus Zenfone ™ 2 Smartphone (Ze551ml) has support for APTX audio codec.

Part II. Macaw T1000 headset review

DATA SHEET

Brand: Macaw.
Model: T1000
Earpiece Design: Earbud (In-Ear
Bluetooth 4.1.
Bilateral Stereo.
Channel: 2.
TRANSMISSION DISTANCE: 10M
CSR8645 Chip.
APT-X Bluetooth Lossless Protocol
Liquipel Waterproof Anti-Sweat
80ma Battery.
170 Hours (7 Days) Standby Time
5 Hours of Continuous Run Time
10 Meters Bluetooth Effective Range

Detailed description from the store page

PROFICIENT TYPE, HIGH QUALITY SOUND
- Top CSR8645 Bluetooth Chip, Multi-Chamfering Optical Coating Technology, Exclusive Custom 12mm Composite Diaphragm
- INSPIRED by The Track and Field Stadium, using Multiple Chamfer Cutting Process, The Beauty of Endless Repetition, Overlap and Delicate Organic
Smaller and Lighter.
- T1000 Total Weight of 15G, Unilateral Headset 5G, Less Than Half The Size Of A Dollar Coin, Light and Comfortable
Powerful Inner Core
- Built-in Britain CSR8645 Top Chip, Supports APT-X Professional Audio Decoding Technology, Range of 360 Decoding Technology, Range of 360 Degrees, The Effective Distance Is More Than 10m Point-to-Point Linear Range Up to 50 Meters
INDEPENDENT ACOISTIC SYSTEM DESIGN
- Customized Version of the 12mm Composite Diaphragm Dynamic Unit, High Resolution, Triple Frequency Balanced, Delicate Vocals, Powerful Bass
INDULGE RUN, FREE WIRELESS
- High Sensitivity Microphone Noise Reduction, Whether You "Re in the Gym, Drive Or Business Negotiation, Hands Free, Enjoy The Quality of the Call
Digital Noise REDUCTION MORE CLEARLY
- Military Grade Braided Nylon Line, Texture, Flexibility, Comfort and Durability
US Liquipel Nano Waterproof Technology, The Effective Water Level Up to IP4
- Note: This Product Is Only Applicable to General Life Waterproof, Is Not Suitable for Long Time Contact Water Environment Like Swimming, Shower, etc.
Ergonomic, Wearing More Comfortable
- Professional Design Team and Acoustic Team Participate in The Design of Cavity and Tuning, More Comfortable In-Ear Design, Not Falling, Long Wear Wear Wear Wear Wear
- No Matter from the Angle of the Wear, Very Comfortable
With Bluetooth, CAN Use Anytime and Anywhere
Fully Compatible with Various Types of Bluetooth Devices On The Market
iPhone Bluetooth Dedicated Power Display
- Let You Know Headphones Electric Power At Any Time
Two Steps, Easy Connection
- When paired with the phone for about 3 Seconds to Boot, Blue Lights Flashing, At The Same Time Do Not Let Go, Continued To Press For 3 Seconds.
- Headphones Prompt "Pairing" Indicator Lights Shows Blue Lights in the Mobile Phone Interface Can Be Connected
Full Scene, Follow Your Heart

Internal structure

PACKAGING

Box is posted in transparent polyethylene.

Photo boxes from different sides.

Unpacking

Top cover on magnets.

EQUIPMENT

The kit includes: headphones, USB-microUSB cable, two pairs of silicone incubuser, spare lining on the headphone body, user manual in Chinese and English and headphone storage and transportation case. The Macaw RT-10 headphones are equipped with a similar case.

APPEARANCE

Headphones are made of plastic, and consist of two halves. Everything is accurate.
Available colors brown and gray.

I chose a brown, because in my opinion, in this color the headphones look more interesting.

On the body of the left headphone, under the rubber plug there is a microUSB connector and a hole of the light indicator.

If you remove the ambush, and the protective cover from the headphone housing, the compensation hole for removing overpressure is seen. The duct yield is closed with a protective mesh.

The cable is very mild and elastic, pleasant to the touch, in a solid nylon overall, under the color of the top of the case. The total length of the cable is 51.5 cm.

Remote Headphones from plastic. On the front side there are three buttons, the volume control buttons and the power button, it is the same answer / hang.

On the reverse side, the microphone hole. Also, on the back, there are round protrusions, thanks to which, the volume buttons are easy to find on the touch.

EASE OF USE. Noise insulation

Headphones are very light (total weight of only 15 grams) and despite the apparent big size, comfortably fit both in the men and in the female ear.
In the female ear.

In men's.

Noise insulation is good. External noise is almost completely isolated. There is also no "rustle" wind. Thanks to the nylon cable lamp, the headphones are completely devoid of microphone effect.

Headset

When you turn on the headset welcomes, and when it is turned off, it says goodbye to a female voice, in Chinese.

Connection

To pair the Macaw T1000 with the device, you need to turn on the Bluetooth on your smartphone and activate the search for other devices. On the headset, clamp the power button for 5 seconds until the indicator lights up in blue.

When the headphones are conjugate with the device, the indicator periodically blinks in blue.

Incoming call

With an incoming call in headphones, a quiet, own melody plays. The subscriber number and the name do not pronounce.

Control

The central button during the call, one-time pressing, long-lasting. Long press the volume button - turn off the microphone. Volume buttons, adjust the volume level.
In music mode, the central button, one-time Pouch / Play. Volume buttons, adjust the volume level. Long-term pressing of the volume button + the next track, on the volume button - the previous track.
Any place is double pressing the central button call the last outgoing number from the call list.

Transmission of Voice

Voice is heard clearly. Volume with stock. Comfortable level, approximately in the middle. Microphone sensitivity is good. The interlocutors do not complain.

Range

In a straight line, no visible barriers distance about 12 meters. Indoor, between two rooms (thick brick wall) Sustainable connection. Sound without stuttering and bungalum.

Working with two phones

Macaw T1000 can work simultaneously with two smartphones. From which phone there is a call, with the sound of headphones. With music similarly.
Double pressing the center of the console button, call the last dialed number, from the phone where the last outgoing call was.

Autonomy. WORKING HOURS

In the mode of continuous playback of music, the volume is slightly above the average, the headset time of 320 minutes (5 hours 20 minutes) was measured personally. Standby time of approximately 170 hours (7 days). When discharged, about 15 minutes before a complete shutdown, the indicator begins to flash in red, and the headphones give voice alert.
Charging time is about 1.5 hours (depending on charger). During charging, the indicator burns in red. At the end of the charging sweeps.

SOUND

Source Sound

ASUS ZenFone ™ 2 Smartphone (ZE551ML)


Player. Music material

On the smartphone, I prefer to use the Ttpod player, because I consider it the most convenient and functional player under the Android OS. The player is really very troubled, a huge online base of high-quality music, loading album covers, lyrics, a bunch of all kinds of settings, supporting the skins and wallpapers of the playback window, output information to Lockscreen smartphone and much more. You can download this player from the official site. Or (if the Chinese version is swinging from the site).
Who is not familiar with this player, I will show a pair of screenshots - a display in Lockscreen mode and playback window.

Using TTPOD as a player, I practically stopped connecting your smartphone to a PC to download music. Online you can find almost any artist and a song.

You can listen to music online, or download files to the Wi-Fi device in advance.
You can choose the quality and format of audio files. I prefer to listen to music online in lossless formats, because both headphones and a smartphone, and the width of the mobile Internet channel, allow you to use all the advantages of wireless technologies.

Sound

I listen to these headphones without equalizer and all kind of improvements.
Headphones are nice. Like previous models, T1000 have a branded recognizable sound - a deep bass and stressed vocals. By sound and manner of feed, this model is similar to RT10. Due to the structural features of the case, it is possible to use a larger diameter driver. Due to what, the study and the depth of the NC became a little better.
The first sensation is a powerful, deep bass, volumetric, dense, shock. Well textured, with clear outlines. Surprisingly, the T1000 manage to play the lower bass well. The blow is perfectly physically, in the form of air vibration in the ear canal. Cool lovers, powerful bass will be satisfied.
The average frequencies accented and underlined. Despite the large number of bass, they sound clearly and open. No complaints. Everything is very vivid, natural and natural.
High frequencies are delicately moved to the background. Not the brightest and air, but detailed and clean, without a hint of screaming. This salvation for those who are as afraid of sharpness and siberiates.
Well passes the volume and depth. Beautiful general detail and separation of sounds. Clear build of virtual plans and positioning of musical instruments and artist in space.

ADVANTAGES AND DISADVANTAGES

Quality materials.
+ Small size and weight.
+ Comfortable, comfortable landing.
+ No wiring clinging.
+ Good, high-quality sound.
For all the time of use, for yourself, I did not find any disadvantages.

Conclusions and impressions

Young, according to the standards of eminent audiomonstrov, the Chinese company Macaw, once again pleased. The novelty turned out really interesting. Positioning this model, in my opinion - first of all these are wireless headphones for listening to music in good quality, and already in the second, headset for conversations.
Lovers of good, high-quality sound, I recommend without any reservations, provided that the source supports APTX audio codec. Only in this case, it will turn out to reveal the entire potential laid in them.

Bought a headset. on Aliexpress

One of the sustainable development trends of mobile devices is to improve the means of wireless communications that provide the ability to connect to the Internet, a local network, as well as with different peripheral equipment (headphones, headsets, acoustic systems, printers, etc.) and other guests nearby gadgets. Technologies wireless communication, as, however, and other components of mobile devices, are constantly evolving. New versions of specifications appear, the bandwidth increases, the set of functions is expanding, etc. This ensures high-quality development, without which technical progress is unthinkable. However, progress has a reverse side: every year the users are becoming more difficult to deal with what the difference between different models is.

Usually from a brief description of a mobile device, you can only learn the names wireless interfaceswhich it is equipped. In the detailed specification, as a rule, there are additional information, in particular, wireless interface versions (for example, Wi-Fi 802.11b / G / N and Bluetooth 2.1). However, this is not always enough to fully appreciate the possibilities of wireless communications of the device under consideration. For example, to understand whether this or that or another peripheral device connected via Bluetooth, with a smartphone or tablet, will be operated.

In this article we will tell about the various nuances that you need to pay attention to the assessment of the capabilities of the devices equipped with the Bluetooth interface.

Scope of application

The wireless interface with a small radius of action, called Bluetooth, was developed in 1994 by the engineers of the Swedish company Ericsson. Starting with the 1998 development and promotion of this technology, the Bluetooth Special Interest Group (Bluetooth Sig), founded by Ericsson, IBM, Intel, Nokia and Toshiba, is engaged in the organization. To date, the list of Bluetooth SIG members includes more than 13 thousand companies.

The introduction of the Bluetooth interface in consumer devices for the mass market began in the first half of the past decade. Currently, the built-in Bluetooth adapters are equipped with many models of portable PCs and mobile devices. In addition, a wide range is available on sale. peripheral devices (Wireless set, manipulators, keyboards, acoustic systems, etc.) equipped with this interface.

The main function of Bluetooth is the creation of so-called personal networks (Private Area Networks, Pan), which provide the possibility of exchanging data between located nearby (inside one house, premises, vehicle, etc.) desktop and portable PCs, peripheral and mobile devices and etc.

The main advantages of Bluetooth compared with competing solutions are the low level of energy consumption and low cost of transceivers, which allows you to embed it even into small-sized devices with miniature power elements. In addition, manufacturers of equipment are exempt from paying licensing deductions for installing Bluetooth transceivers in their products.

Connecting devices

Through the Bluetooth interface, you can combine both two and several devices at once. In the first case, the connection is carried out according to the "Point - point" scheme, in the second - according to the "Point - Multipoint" scheme. Regardless of the connection scheme, one of the devices is the lead (master), the remaining - slave (Slave). The master device sets the template that all driven devices will use, and also synchronizes their operation. The devices are connected to the Piconeet (Piconet). Within one picoseti, one leading and to seven slave devices can be combined (Fig. 1 and 2). In addition, additional slave devices (over seven) are allowed, which have the status of blocked (PARKED): they are not involved in the exchange of data, but at the same time are in synchronization with the master device.

Fig. 1. Pico Scheme,
combining two devices

Fig. 2. Picoseti scheme,
unifying several devices

Several picosets can be combined into a distributed network (Scatternet). To do this, a device operating as a led in one picotter must perform the functions of the master in another (Fig. 3). Picotions that are part of the same distributed network are not synchronized with each other and use different templates.

Fig. 3. Distributed network scheme, including three picosetics

The maximum number of picosets in the distributed network cannot exceed ten. Thus, the distributed network allows you to combine a total of up to 71 devices.

Note that in practice the need for the creation of a distributed network rarely occurs. With the current degree of integration of hardware components, it is difficult to imagine the situation when the owner of a smartphone or tablet would need to connect more than two or three devices by Bluetooth simultaneously.

Radius of action

The Bluetooth specification provides three classes of transceivers (see table) differing in power, and therefore, according to an effective radius of action. The most common option that is used in most of the now available mobile electronic devices and PCs are Bluetooth Class 2 transceivers 2. The Class 3 low-power systems are equipped with medical equipment, and the main area of \u200b\u200bapplication of the most "long-range" modules Class 1 are monitoring and control systems for industrial equipment.

Of course, it is possible to count on a stable wireless connection between devices removed at the limit distance (for example, 10 m in the case of Class 2 transceivers), only in the absence of large-sized obstacles between them (walls, partitions, doors, etc.). The actual radius of action may vary both depending on the characteristics of the room and on the presence of radio interference and sources of strong electromagnetic radiation.

Bluetooth versions and their differences

The first version of the specification (Bluetooth 1.0) was approved in 1999. Shortly after the intermediate specification (Bluetooth 1.0V), Bluetooth 1.1 was approved - errors fixed in it and many shortcomings of the first version were fixed.

In 2003, the BLUETOOTH 1.2 base specification was approved. One of its key innovations was the introduction of an adaptive operating frequency reconfiguration method (Adaptive Frequency-Hopping Spread Spectrum, AFH), thanks to which the wireless connection has become much more resistant to electromagnetic interference. In addition, it was possible to reduce the time spent on executing the procedures for detecting and connecting devices.

Another important improvement in version 1.2 was to increase the rate of data exchange to 433.9 kbps in each direction using asynchronous communication on a symmetrical channel. In the case of an asymmetric channel, the bandwidth was 723.2 kbps in one direction and 57.6 kbps - to another.

An improved version of synchronous communication technology with a connection is also added (Extended Synchronous Connections, ESCO), which made it possible to improve the quality of streaming sound due to the application of the re-sending mechanism damaged during the transmission process.

At the end of 2004, the Bluetooth 2.0 + EDR Basic Specification was approved. The most important innovation of the second version was the technology of Enhanced Data Rate (EDR), thanks to the introduction of which it was possible to increase the interface bandwidth (several times). Theoretically, the use of EDR allows you to achieve a data rate of 3 Mbps, however, in practice, this indicator usually does not exceed 2 Mbps.

It should be noted that EDR is not a mandatory function for transceivers corresponding to the Bluetooth 2.0 specification.

Devices equipped with Bluetooth 2.0 transceivers are compatible with the modules of previous versions (1.x). Naturally, the data transfer rate is limited to the capabilities of a slower device.

In 2007, the basic specification of Bluetooth 2.1 + EDR was approved. One of the innovations implemented in it became the energy-saving Sniff Subrarating technology, which allowed significantly (from three to ten times) to increase the duration of the autonomous operation of mobile devices. The procedure for establishing a connection between two devices was also significantly simplified.

In August 2008, basic additions were approved (Core Specification Addedum, CSA) to the Bluetooth 2.0 + EDR and Bluetooth 2.1 + EDR specifications. The changes are aimed at reducing the level of energy consumption, increasing the level of protection of the transmitted data and optimizing identification procedures and connecting Bluetooth devices.

In April 2009, the Bluetooth 3.0 + HS basic specification was approved. The HS abbreviation in this case is decrypted as high speed (high speed). Its main innovation is the implementation of Generic Alternate Mac / PHY technology, which provides the ability to transfer data at a speed of up to 24 Mbps. In addition, it is envisaged to use two modules of transceivers: low-speed (with low power consumption) and high-speed. Depending on the width of the translated data stream (or size transmitted file.) Enables either low-speed (up to 3 Mbps) or high-speed transceiver. This reduces the level of energy consumption in situations when the data is not required.

BLUETOOTH 4.0 basic specification was approved in June 2010. The key feature of this version is the application of low-power data transmission technology (Low Energy Technology). The reduction in power consumption is achieved both by limiting the data transfer rate (no more than 1 Mbps) and due to the fact that the transceiver does not work constantly, and only turns on the time of data exchange. Contrary to common misconception, the Bluetooth 4.0 interface does not provide a higher data transfer rate compared to the Bluetooth 3.0 + HS version.

Bluetooth profiles

The ability to interact the devices when connected via the Bluetooth interface are largely determined by the profile set, which supports each of them. This or that profile provides support for certain functions, such as file transfer or media stream, providing a network connection, etc. For information on some Bluetooth profiles are shown in the insertion.

It is important to understand that you can use a Bluetooth connection to perform a kind of task, only with the support of the appropriate profile of both the lead and the driven device. Thus, to transfer the Bluetooth connection "Business Card" or contact from one mobile phone to another can only be provided that both devices support OPP profile (Object Push Profile). And, for example, to use a mobile phone as a wireless cellular modem, it is necessary that this machine and computer connected to it support DUN profile (Dial-Up Networking Profile).

Often there are situations where the Bluetooth connection between two devices is set, however, it is not possible to perform the action (say, the file) fails. One of the probable causes of such problems may be lack of support for the appropriate profile from one of the devices.

Thus, the set of supported profiles is an important factorthat must be taken into account when evaluating the possibilities of a particular device. Unfortunately, in some models of mobile devices, a minimum set of profiles is maintained (for example, only A2DP and HSP), which significantly limits the capabilities of the wireless connection to other equipment.

Note that the set of supported profiles is determined not only by the specifics and constructive features Devices, but also by the manufacturer's policy. For example, in some devices, the possibility of transmitting files of certain formats (images, videos, electronic books, applications, etc.) under the pretext of combating piracy is blocked. True, in fact, not lovers of counterfeit media system and software suffer from such restrictions, and honest users who are forced to transfer to the PC to the PC to the PC (for example, sending the desired files to their own email address).

Bluetooth profiles A2DP. (Advanced Audio Distribution Profile) - Provides the transfer of a two-channel (stereo) audio stream from the source of the signal (PC, player, mobile phone) to a wireless stereo header, an acoustic system or a different reproductive device. To compress the transmitted stream, the standard SBC codec (Sub Band Codec) can be used or another determined by the device manufacturer. AVRCP (Audio / Video Remote Control Profile) - allows you to manage standard functions televisions, home cinema systems, etc. The AVRCP profile device is capable of performing a wireless remote control function. Can be used in conjunction with A2DP or VDPT profiles. Bip. (Basic Imaging Profile) - Provides the ability to transmit, receive and view images. For example, allows you to transmit digital photos from a digital camera to a mobile phone memory. It is possible to change the size and formats of transmitted images, taking into account the specifics of the connected devices. BPP. (Basic Printing Profile) is a basic print profile that provides the transmission of various objects (text messages, business cards, images, etc.) to output on the printing device. For example, you can print a text message on the printer or a photo from a mobile phone. An important feature of the BPP profile is that the device from which the object is sent to print cannot be installed a specific driver for the available printer model. Dun. (Dial-Up Networking Profile) - Provides a PC connection or other device to the Internet by means of a mobile phone that performs an external modem function in this case. Fax (Fax Profile) - allows you to use an external device (mobile phone or MFP with a facsimile module) for receiving and sending facsimile messages from a PC. FTP. File Transfer Profile) - Provides file transfer, as well as access to the file system of the connected device. The standard set of commands allows you to navigate through the hierarchical structure of the logical disk of the connected device, as well as copy and delete files. Gavdp. GENERAL AUDIO / VIDEO DISTRIBUTION PROFILE) - Provides the transmission of sound and video stream from the signal source to the reproducing device. It is the basic for A2DP and VDP profiles. Hfp. (Hands-Free Profile) - Provides connection car devices Hands-free to a mobile phone for voice communication. Hid. (Human Interface Device Profile) - describes protocols and ways to connect wireless input devices (mice, keyboards, joysticks, remote controls, etc.) to PC. HID profile is supported in a number of mobile phones and PDA models, which allows them to be used as wireless control panels. graphical interface OS or individual applications on the PC. HSP. (Headset Profile) - allows you to connect a wireless headset to a mobile phone or other device. In addition to the transmission of the sound stream, the operation of features such as a set of numbers is ensured, the answer to incoming callCompleting the call and adjust the volume. OPP. (Object Push Profile) - a basic profile for sending objects (images, business cards, etc.). For example, you can transfer the list of contacts from one mobile phone to another or a photo from a smartphone on a PC. Unlike FTP, OPP profile does not provide access to the file system of the connected device. Pan. Personal Area Networking Profile - allows you to combine two or how much devices in the local network. In this way, you can connect a few PC to one, which has access to the Internet. In addition, this profile provides remote access to a PC that performs the functions of the master device. Sync. (Synchronization Profile) - Used in a bundle with the GOEP base profile and synchronizes personal data (diary, contact list, etc.) between two devices (for example, H Astol PC and mobile phone).

Manufacturers constantly inspire consumers that new solutions are definitely better than old. New processors have higher performance and less power consumption compared to predecessors; New displays have a higher resolution and wide color coverage, etc. However, it is hardly advisable to apply a similar approach to estimate the capabilities of the Bluetooth interface.

First, it is necessary to take into account the features of the already existing Bluetooth-devices Park. After all, as already mentioned, the maximum data transfer rate is determined by the device equipped with the most old version interface. In addition, high data transfer rate is not required for all tasks. If to copy media files (audio records, images) or broadcast sound stream with a low compression, this is a really important factor, then for normal phone interaction with a wireless headset or for exchanging contacts with another device, Bluetooth 2.0 is enough.

Associated, in many cases a much more important factor than the maximum wireless speed, is a set of supported Bluetooth profiles. After all, it is he actually determines the circle of equipment with which the available device can interact. Unfortunately, this information rarely is rarely given in the full specification of the device, and often they have to search in the text of the operating manual or on user forums.

Any sound starts with a source. Today there is a mass of wireless protocols to transmit sound. Some of them are much more interesting than Bluetooth, but have not yet received proper propagation. Today, Bluetooth is equipped with almost all smartphones, laptops and tablets, and to equip the device with its support in the presence of a USB output is a matter of five minutes.

Therefore, today we will restrict ourselves to the sound well-reproducing devices using a "blue tooth" (the guide is quite suitable for the choice of Bluetooth speakers). This technology has a rather long history and mass of pitfalls, the existence of which users do not always know.

The presence of a Bluetooth transmitter does not mean that the device can be used as a sound source for wireless audio equipment. Not every Bluetooth will allow you to listen to high-quality music without distortion. Not everyone comes up for listening to the files with a high bit rate and in Lossless formats.

What to pay attention to listening to music without wires - be it just mp3 or high-quality rip with vinyl record, we will tell in this article.

Let's start with the most important: this parameter does not directly indicate whether you can listen to the music using the device.

VersionBluetooth

In modern devices, you can most often meet the support of Bluetooth 3.0 or 4.0, in some top smartphones and other gadgets - 4.1. In this case, it may well be that the acquired headset supports connection only by version 2.1. Adapters are inversely compatible, but when connected, the most slow protocol is running.

The difference between the protocol versions for the regular user is minimal at the expense of backward compatibility. The main thing that rushes into the eye is, with each new version, the power consumption of devices is reduced, and starting with 3.0 the second module for high-speed data transmission at 24 Mbps is added.

Version 2.1 + EDR transmits data at no more than 2.1 Mbps. This is enough to play a low bitty audio stream. To play an audiovideo movement, it is recommended to use the Bluetooth version of not below 3.0.

It is necessary to take into account that for the full use of the device as a player, it is extremely desirable Bluetooth version 4.0 and above, and better - with reduced power consumption.

You can identify such an adapter thanks to the following categories.

ProfilesBluetooth

Profiles - a set of specific features supported by devices. Of all those used in Bluetooth, the following are interesting for listening:

1. HEADSET PROFILE (HSP) We are required to communicate a headset and smartphone and a wireless transmission of a monozoque with a bit rate of 64 kbps.
2. Hands-Free Profile (HFP) It also provides mono transmission, however with higher quality.
3. ADVANCED AUDIO DISTRIBUTION PROFILE (A2DP) We are needed to transmit two-channel audio streams.
4. Audio / Video Remote Control Profile (AVRCP) Provides control of the functions of reproducing devices (without it is not possible to change the volume of music).

For a full listening of music you need A2DP. It not only provides the transmission of the audio stream, but also manages the data compression before the transmission.

However, even if the transmitter, and the reproducing device (for example, a smartphone and wireless headphones) are equipped with Bluetooth 3.0 or 4.0 and support work with the necessary protocol, you need to pay attention to the codec that is used.

CodecsBluetooth

The most important thing to play music via the A2DP protocol is a codec that is compressed by the audio flow transmitted to the headset. In total, there are three codecs at the moment:

1. Subband Coding (SBC)- The codec used by the default A2DP and created by the profile developers. Unfortunately, SBC pums greatly rude than mp3. And it became, not suitable for listening to music.
2. Advanced Audio Coding (AAC)- A more advanced codec using other compression algorithms. Sounds significantly better than SBC.
3. APTX- Here he is the right choice! At least due to the ability to transfer files to MP3 and AAC without additional manipulations and transcoding. So, without worsening sound. However, it is worth a reservation. There are several APTX versions for playing different bitrates. Each of them is designed for its sound flow.

Version	Number of supported channels	Maximum discretization frequency, kHz	Quantization, bit	Maximum bitrate	Compression ratio
APTX	2	44,1	16	320 kbps	2:1
Enhanced APTX	2, 4, 5.1, 5.1+2	48	16, 20, 24	up to 1.28 Mbps	4:1
APTX Live.	n / D.	48	16, 20, 24	n / D.	8:1
APTX LOSSLESS.	n / D.	96	16, 20, 24	n / D.	n / D.
APTX Low Latence	N / D.	48	16, 20, 24	n / D.	n / D.

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The main features of the last two versions of the codec are the maximum reduced retention of sound reproduction and a reduced load on the processor when encoding. The Low Latency version allows you to achieve a delay of 32 ms between the source of the audio stream and the reproducing device. This will reduce the distortions introduced by equipment while listening to music.

Thus, with certain preferences, you can select a specific codec. If the Lossless stream play is not assumed, and the high audio delay is not critical - it is worth limited to the standard APTX and not overpay for support for subsequent versions.

It is worth remembering that the necessary profile and codec must be supported as a smartphone (or another source of audio stream) and the headset itself (or Bluetooth column). Otherwise, the A2DP algorithm will automatically start working using SBC.

C Bluetooth Any two devices always work using the lowest version, the simplest codec and protocol. So, if one of them does not have the support of the necessary technology, it will not be possible to fully enjoy the quality of the sound.

For listening to music for a long time, Bluetooth support is required not lower than version 3.0, APTX codec and A2DP profile. To listen to music with a high bit rate, support for the APTX Lossless codec is needed - no other will fit, because the music will be compressed when transmitting to a reproducing device.

Bluetooth technology is named after Harald of the Sanezube, the ancient King of Vikings. And for the sake of the Most High, do not ask why. It is better to deal with really important things: how it is arranged, which is capable of what is interesting - and what is not interesting - Melomanana. And most importantly, what happens to the audio stream when he leaves a smartphone or tablet to get to wireless headphones or a Bluetooth channel speakers.

Today, without the support of Bluetooth, it is impossible to imagine neither a smartphone nor a tablet, nor any other self-respecting mobile device. However, the technology itself was born wherever the smartphones and tablets - back in 1994, and its initial goal was to replace the wires in the filling of telecommunication stations.

Initially, the "blue tooth" had a lot of problems with the speed and reliability of communication, energy intensity and compatibility between various devices, but over time the technology has grown, with each new version becoming noticeably more accurate, more economical and more.

In the photo, Harald I, the blueness takes baptism. According to the legend (unconfirmed), the king united Danish settlements into a single country. This fact has become the idea for Bluetooth - link all devices with one protocol

Some improvements - for example, simplifying the "pairing" procedure in version 2.1 and a serious reduction in the load on batteries in the current version 4.0 - made daily life Melomanians are noticeably comfortable. Even more comfort has made the appearance of NFC technology - in the bundle with it Bluetooth does not require any ceremonies with the mutual recognition of the receiver and the transmitter, just touch the gadgets to each other. But in general, on the quality of the transmission of sound, the progress was reflected in a little: in the latest Bluetooth edition, this process is arranged in the same way as in his last version of the ten-year old. And actually how?

35 blue teeth

Like the overwhelming majority of other wireless interfaces, Bluetooth is based on the use of radio waves. For the transmission of information "Blue Tooth" uses radio frequencies in the 2.4 GHz area - here in the neighborhood "graze" Wi-Fi-routers, wireless computer keyboards and mice, some DECT phones and the mass of other equipment.

What is the difference between Bluetooth from many other wireless technologies? On the one hand, relatively low long-distance: the radius of its action does not exceed a dozen meters, and thick walls can additionally reduce this indicator.

What is curious, the Bluetooth logo consists of two Scandinavian runes: "Haglaz" and "Berkan" (Latin letters analogues H and B)

On the other hand - multifunctionality. The "Blue Tooth" can be used in a wide variety of purposes: from the transfer of pictures on a laptop to sending documents to print, from managing external devices to streaming audio streaming. It is not surprising that Bluetooth has so many different so-called. "Profiles", each of which ensures the execution of a particular task, determining technical specifications Interactions between the Bluetooth transmitter and the receiver. The total number of profiles is measured with tens (according to the article on the Wikipedia base 35 pieces), only three correspond to the transmission of sound. What do they differ from each other?

Bluetooth Profiles HSP, HFP and A2DP

The first Bluetooth audio profile is named HSP - Headset Profile. As can be understood from the name, it is designed to work with mobile headsets and is sharpened to the basic transmission of voice with all the consequences resulting from here: the audio is allowed only in mono format and with a bit rate not higher than 64 Kb / c. Compared to this sound, even pushed MP3 seems to be divine pleasure for the ears.

The second - HFP, Handsfree Profile - is a slightly more advanced version of the same profile. Its addressee is all the same monophonic headsets, so the stereo is still not supported, but the sound quality is somewhat higher. However, for listening to music, this profile is still not suitable.

As soon as A2DP appeared, many HI-FI manufacturers paid attention to it. But before all there were small companies that made adapters as the Gogroove Bluegate described in the photo, a small box with a DAC and headphone amplifier inside.

For this purpose, a special A2DP profile is provided - Advanced Audio Distribution Profile. It is he who is responsible for connecting mobile devices with wireless columns and headphones. The A2DP profile allows the sound source to find a common language with wireless acoustics, and most importantly - controls the compression of the audio to send the channel to the "blue-refrigera". It is impossible to avoid this procedure due to the low Bluetooth bandwidth, but the level of compression used to compress the algorithms and, ultimately, losses as sound can be markedly vary. Here, as they say, the nuances arise.

SBC codec rogue mp3

As you know, compress the sound can be different. With losses as or without them, with a low or high bit rate, with various settings, using different codecs. Instead of some of the universally common codecs for compressing the audio flow in the A2DP profile, the default compression algorithm is applied by the Subband Coding - or, simply, SBC.

A comparison conducted by Bart Buttervut (author about.com) shows the difference in which noises occur when tone 5, 10, 12.5 and 20 kHz. Blue Line - APTX, Green - SBC ()

Sound processing according to SBC methods has a lot in common with a good all familiar MP3 compression, but priorities are built somewhat differently: the main task is not so much to minimize sound losses how much to simplify the calculations. Everything must be quick, simple and easy to do even for the most harvested mobile processor.

As a result, the SBC costs the sound without unnecessary ceremonies - for example, frequencies above 14 kHz during conversion is simply cut off, with the result that the frequency range is noticeably narrows. It is not surprising that even with an equal bit rate with MP3 (and SBC allows a bitrate to 320 kb / c) audio in SBC encoding sounds noticeably worse.

This graph shows the spectra when broadcasting 1 kHz signal via APTX (Blue) and SBC (green), as well as 4 kHz - APTX (purple) and SBC (red) ()

As a result, when using a default encoder, Bluetooth worsens the sound of not only uncompressed audio, but also normal MP3 files - after all, in the process of wireless transport, they are first decoded, and then compress again, this time where is gross. Fortunately, SBC is the main, but not necessarily the only tool for the compression of the audio flow, which is available in A2DP arsenal. There are other, more interesting offers.

Advanced Audio Coding: Advanced, but not perfect

The basic SBC codec with its modest musical abilities is not the best tool to draw the attention of music lovers to Bluetooth technology. That is why the developers of many "blue-reform" devices, especially in the top segment, are equipped with A2DP profile optional, more advanced sound compression. The most popular of these funds is the AAC algorithm.

Unlike the SBC codec, a friend is unless that lovers dug in the technical specifications of Bluetooth, AAC abbreviation is not bad known to wide folk masses. Still would! After all, this format is used, for example, in iTunes. The initial task of the developers of the algorithm was to surpass MP3 in terms of sound quality with the same bitrates - it's not by chance that its name is decrypted as Advanced Audio Coding, "advanced sound coding".

At the expense of more complex AAC algorithms really retains more musical information than mp3, and even more so SBC. It is not surprising that its inclusion in the set of codecs supported by the A2DP profile, significantly improves the sound of Bluetooth speakers and headphones.

The main thing is to make sure that the AAC codec is supported by both "synevs" devices: and by what serves as a transmitter of the audio signal, and what works at its reception. If, from a pair of such devices, AAC encoding is able to understand only one - the A2DP profile automatically rolls back to the base codec. With quite obvious consequences for sound.

APTX codec: Best option for music love

Even more advanced sound compression provides APTX codec, which actively promotes the CSR Bluetooth-audio market. The creators promote it as a means for wireless music transmission "in CD-quality".

APTX codec has its own logo, because it is designed and patented by CSR

In fact, this is not quite so, although the algorithms underlying APTX, according to the principle of their work, really resemble lossless encoders that seal audio streams without losing sound information. Among the advantages of APTX is the ability to Bluetooth-broadcast MP3 and AAC without additional processing, which means that without a worsening sound.

Special version of APTX Low Latency, sharpened under the requests of gamers and kinomans, provides also minimum delay In the delivery of the signal - and therefore, watching a movie without backward replicas from the facial expressions of characters.

The APTX codec provides audio transmission with a bit rate to 352 Kb / s, does not cut up the upper register and spreads the frequency range to quite solid 10 Hz - 22 kHz, but the high complexity of the algorithms used requires from mobile processors of tripled computing power compared to the base SBC. That is why the support of APTX meets among the "blue-refine" devices quite rarely, most often in the premium segment of smartphones.

However, in order to become the owner of a smartphone with APTX, it is not necessary to lay out so much cash: in the catalogs Samsung, Sony, HTS and ASUS presented a lot of models with support for advanced codec, including quite affordable.

As in the case of AAC, with wireless connection Sound source with speakers or headphones should be verified that the APTX codec is supported by both devices. Only in this case can not be doubted that you really squeeze the maximum of its musical potential from the "blue tooth".

Mobile devices today are not only directly intended - calls, and and multimedia entertainment centers. On smartphones and communicators, you can watch movies, create photo albums, play, surf through the spaces of the Internet, and listen to music. Music listened and always listen. But what is needed by mobile devices, more accurately, which should support functions and accessories Telephone for such a musical pleasure, we will find out today.

The first accessory with which you can listen to the musical works on the smartphone are headphones -.

- (from English. Free Hands) System, which allows to speak and manage the phone without hands. Most often applied in cars. In essence, it is devices that provide the ability to conduct a conversation without holding a mobile phone, the communicator in hand. Consists of a headset and microphone. There are wired and futulated Hands FREE.

Wired headsets are connected with a mobile device using a cord. They, in turn, are divided into mono and stereo headsets. There are also multimedia HandsFree, allowing you to control the player of the mobile device.

A wireless headset connects with a mobile device using. It is capable of catching a mobile phone signal at a distance of up to 10 m.

Bluetooth wireless technology is irreplaceable to equip mobile phones with various external devices such as HandsFree, external memory or wireless modems. Recently, Bluetooth headsets and headphones () are becoming increasingly popular. Some of them have the ability to work not only with mobile phones and PDA, but also with other devices that do not have a protocol Bluetooth stereo Through adapters.

The appearance of phones supporting the ability to use wireless Bluetooth Street handicrafts for listening to music, allowed their owners to feel real joy from the complete lack of wires. However, the cost of such phones and Bluetooth headphones themselves does not allow us to talk about the mass of this phenomenon.

Stereo Bluetooth Headphones cannot work with a mobile device if the profile is not supported on the latter.