How Bluetooth Speaker Works

How Bluetooth Speaker Works

Bluetooth is a short-range wireless transmission technology that allows the exchange of data, including audio, between different fixed or mobile devices (computers, smartphones, tablets, speakers, amps, televisions, headphones, etc.).

Bluetooth technology allows music to be wirelessly streamed from a smartphone to a Bluetooth speaker.

 

Bluetooth wireless Speaker connection: what’s the point?

Ideal for removing cables between a computer or video game console and its devices (keyboard, mouse, PS4 and Xbox One controllers, printers, etc.), this technology is also booming with the democratization of mobile telephony. Low energy consumption, Bluetooth is indeed particularly suitable for wirelessly connecting mobile devices. Initially confined to wireless headsets for hands-free telephony, this mode of transmission quickly spread to the music field and is now implanted on many wireless stereo headsets and speakers and channels dedicated to mobile phones and touch tablets.

 

When was Bluetooth technology?

Invented in 1994 by engineers from the Swedish communications company Ericsson, Bluetooth technology owes much to military research on transmissions initiated since the 1940s. As early as 1998, several manufacturers joined forces around Ericsson to work on the connections of their respective devices using this technology, forming the Bluetooth SIG (Special Interest Group), a group that ensures the development of the technology. Several standards have followed one another, each bringing their share of improvements, notably in terms of data flow.

 

Where does the name Bluetooth come from?

In English, Bluetooth means “Blue Tooth.” This is how the Danish king Harald I (Harald Blatant, “blue tooth” in Danish) was nicknamed, which unified the kingdoms of Denmark, Sweden, and Norway in the 10th century. By analogy, this name was given to this technology developed in a Nordic country and designed to allow electronic devices of different origins to work together.

 

How does data transmission work in Bluetooth?

Like many wireless transmission technologies, Bluetooth technology uses radio waves. The big difference with other radio transmission modes such as FM or TNT is the range: where radio and TV broadcast for miles to reach thousands of people, Bluetooth is intended for personal use in a restricted field. By analogy with the acronym WLAN (Wireless Local Area Network), we are talking about WPAN, Wireless Personal Area Network, Wireless Personal Network. The average field of action of a Bluetooth link is thus about ten meters and can not exceed fifty meters in the best case. The frequency band used is between 2,402 and 2,480 GHz, cut into 79 channels of 1 MHz—the transmission isne using a combination of channels that constantly changes to avoid interference with other radio signals.

 

What is Bluetooth pairing?

The Bluetooth standard was originally designed to link only two devices, a “master” device and a “slave” device. To communicate with each other, a smartphone and a Bluetooth device must be linked, so-called “appaired,” most often utilizing a code provided by the device that must be entered on the phone (often 0000). The phone then keeps the code in memory so that the next pairings are faster and are done simply by selecting the device from a list. Today, with advances in Bluetooth technology helps, it is common to find Bluetooth speakers, capable channels, or auto radios that support multiple pairing (2 or more smartphones paired with the same Bluetooth speaker).

 

What is the A2DP?

The Advanced Audio Distribution Profile (A2DP) is a high-quality audio transmission standard used with Bluetooth technology to, for example, deliver the sound of a smartphone to a wireless headset. This standard is compatible with stereo sound and works one way, from the transmitter to the receiver. A2DP audio streaming typically uses the SBC codec with a speed of up to 128 Kbps.

 

What is AVRCP?

The Audio Video Remote Control Profile (AVRCP) allows control of audio-video streaming directly from the receiver (helmet or speaker). In practice, this allows you to change the song directly on the headphones or speaker via a dedicated key without having to intervene on the smartphone or tablet that emits the music.

 

What is apt-X?

Compatible with Bluetooth A2DP Stereo devices, the apt-X codec offers a quality relatively close to CD-Audio. With an average compression ratio of 4:1, the music listened to is of outstanding quality. FLAC, Apple Lossless, or PCM files transmitted via this protocol are relatively ungraded. MP3 or AAFC files with a speed of fewer than 350 Kbps are transmitted without transcoding or deterioration. The dynamic margin is 92 dB, the quantification of 16 bits, and the frequency response between 20 Hz and 22 kHz (like the CD-Audio). Besides, the apt-X codec is compatible with conventional Bluetooth SBC systems.

The Low Latency version of the codec apt-X lowers the latency time between the 150 ms audio signal (standard Bluetooth) to only 32 ms. This very low latency allows you to enjoy the sound of videos or games of a smartphone or tablet on a Bluetooth speaker without having to endure a lag between image and sound.

With the apt-X Low Latency codec built into the Plantronics Backbeat Pro 2 Bluetooth headset, enjoy your wireless, latency-free programs, games, and music.

The aptX HD is a version of the apt-X codec optimized for The Bluetooth transmission of HD audio files up to 24 bits/48 kHz. This codec is retro compatible with previous aptX codecs.

 

What are the Bluetooth HSP and HFP profiles?

The HSP (Headset Profile) profile and the Hand-Free Profile (HFP) profile support the hands-free telephony function. This is the case for the vast majority of Bluetooth wireless headsets but also some Bluetooth speakers. The HSP or HFP-enabled headset or speaker includes a microphone to transmit your voice to the caller, as well as a dedicated button for making calls and hanging up. To optimize the quality of the conversation, it may be useful to opt for a device with a noise-reducing microphone.

 

What is the Bluetooth IOPT profile?

IOPT is an interoperability profile. This profile defines how devices can communicate with each other without requiring the entry of a security key. Many wireless devices such as mice or keyboards use WiFi or radio frequencies in a one-way way use of a particular frequency but do not have the ability to network. These devices send data (pointer movements, left or right-click, hit a particular key) but do not network with another device. The IOPT profile defines all the protocols necessary to accomplish this without entering a security key since the two products that need to be communicated have already been paired for the first time.

Since version 3.0, the Bluetooth standard integrates the IOPT profile as standard. Even though it is rarely mentioned in the list of functions of a particular Bluetooth device, this means that if you use a Bluetooth 3.0 or higher device, your device connects automatically, without the need to enter a security key each time.

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