Inside A Bluetooth Speaker

Naidelyn Castellanos

ENGL 21007: Writing for Engineering

Professor Von Uhl
April 13, 2022

Table Of Contents

History of the Bluetooth Speaker

Speakers………………………………………………………………. 3  

Bluetooth………………………………………………………………. 3

Interior Of Bluetooth Speaker

Speakers………………………………………………………………. 4

Batteries………………………………………………………………. 5-6

Audio…………………………………………………………………. 6

 Types of Circuit Boards……………………………………………….6-8

Bluetooth Speaker Purpose

Functions …………………………………………………………8-9

Conclusion …………………………………………………………9

Reference Page …………………………………………………………10-11

History of the Bluetooth Speaker

Before getting into the Bluetooth speaker we have to understand how the two components originated and were created. The speaker was created long before Bluetooth in 1861 by two men named Johann Philipp Reis and Alexander Graham Bell who were both “profound” inventors already. Resi installed an electric loudspeaker on his telephone to reproduce clear tones audio and Bell developed the first loudspeaker to produce intelligible speech. The speaker’s objective was to give off audio output to listeners and throughout this time the inventors kept updating and innovating the speakers.

Just as everyone in society today can not live without their phone, Bluetooth is just as useful now. This all started with a man named Jaap Haartsen who led a team to develop what is now known as Bluetooth in 1994. Haartsen got his degree in electrical engineering in 1986 from the University of Delft which is located in the Netherlands. Haartsen was an expert at wireless communication who was working at Ericsson, a leading provider of information and communication. Haartsen was tasked with finding short-range radio connections that would add functionally to mobile phones and enable new sales.

After being active in wireless communication for more than 25 years on May 7th of 1994, Haartsen put out a foundation for the system of Bluetooth wireless technology which enables connection between a seemingly endless array of devices. Furthermore, the Bluetooth speaker was not the first thing to be released; it was a Bluetooth phone and its launch in 2001 was a Sony Ericsson T36 but the one that was released was a T39 model. The Bluetooth speaker includes amplifiers and speakers that connect via Bluetooth wireless this means no connecting cables. It

would work on any type of smartphone, tablet, and computer. The built-in speaker allows the amplification of audio.

Interior Of Bluetooth Speaker

Speakers

The major part of any type of Bluetooth speaker is the speakers and Inside of a speaker sound would move in pressure waves. When air particles are compressed and rarefied fast enough, we hear it as a sound. The faster the air pressure changes, the higher the “frequency” of the sound we hear. When a speaker moves back and forth it pushes on air particles which changes the air pressure and creates sound waves. Speakers work by converting electrical energy into mechanical energy motion (Rohan C, 2022). The mechanical energy compressed air and converts the motion into sound energy or sound pressure level (SPL). The parts that make up a speaker are called the cone and the first cap which would be the parts that move air and produce the sound, next is the suspension which is nicknamed the spider, and the surrounding these allow the cone to stay in place while giving them the ability to move. Then the magnet and the voice coil which reasons behind are to interact to convert electric energy into motion. Finally, the basket, pole, top plate, and frame make sure components stay together.

Figure 1

Batteries

Usually, the battery’s life depends on what type of battery is inputted and the size of the Bluetooth speaker. In this case, we are mostly focusing on the Bose speaker but on average they are around 1000mAH to 4000 mAH. Bluetooth speakers also use more power than standard Bluetooth devices so their battery life is shorter (Rohan C, 2022). But the most common battery in Bluetooth speakers is called a Li-ion battery. The reason why these batteries are the most common for a Bluetooth speaker is that they have been tested to be more safe, reliable, and efficient, not to mention they provide a very strong power that can make the audio last long for many hours once it reaches 100 percent.

The Li-Ion battery is short for a Lithium-ion battery. This battery is made up of different “cells that are connected to one another. Each cell contains three main parts: a positive electrode (a cathode), a negative electrode (an anode), and a liquid electrolyte. Furthermore, recharging the li-ion is done “by moving through the electrolyte until they reach the positive electrode. There, they are deposited. The electrons, on the other hand, move from the anode to the cathode(Chapman, 2019).

Figure 2

Note: (Left of the image) On the discharging side the lithium ions can move through (intercalate) the cathode and anode. When you charge a lithium-ion battery, the exact opposite process

happens. The lithium ions move back from the cathode to the anode. The electrons move from the anode to the cathode(Chapman, 2019).

(Right of the image)On the charging side, as long as lithium ions are making the trek from one electrode to another, there is a constant flow of electrons. This provides the energy to keep your device running. Since this cycle can be repeated hundreds of times, this type of battery is rechargeable(Chapman, 2019).

Audio

In audio devices, the key difference in Bluetooth implementation involves which audio codec they use. A codec(short for “compression/decompression”) is a complex algorithm that processes audio data to make it smaller so it’s easier to send over the Internet or wirelessly from your phone to your headphones. You’ve probably heard of some popular codecs used today, including SBC, AAC, aptX, and MP3. Using a codec is necessary because the less data Bluetooth needs to transmit, the more reliable( Butterworth, 2020).

Types of Circuit Boards

The idea behind the Circuit board in a Bluetooth speaker is what drives wireless headsets, remote controls, and wireless speakers to the Internet of things/applications. They are composed of two-layered PCBs but have only a single plate. There would be layers on both sides of the leaves. Many different types of circuits could be found in a Bluetooth speaker but the most common ones usually have an antenna located on the Bluetooth PCB, which receives the signal sent out by a Bluetooth device. The message is then sent to the output after being processed

inside the circuit board. The circuit board may have a minimum of 2 inductors, which can fine-tune the antenna’s impedance to improve the reception and sending of information.

The circuit board inside the speaker contains multiple purposes because it has different segments dedicated to Bluetooth, audio amplification, voltage balancing, and battery charging. The circuit board has two sides that function for different things.

voice calls. You will also find the speakers, battery, and a secondary circuit board, which supplies USB power, power buttons, and LEDs.

The Bluetooth circuit board comes with an IC, which makes up the Bluetooth system of the board. The IC can be used for any wireless audio component. The Bluetooth speaker includes the transmitter circuit board. This covers the sensor data to the wireless transmission for your convenience. The Bluetooth transmitter circuit board has three significant components- regulated voltage, sensor data, and wireless transmission. The regulated voltage is responsible for supplying power to the sensor circuit, Bluetooth transmitter, and microcontroller.

Bluetooth Speaker Purpose

Function

The big difference between a speaker and a Bluetooth speaker is the wireless transfer of audio via Bluetooth rather than the typical wired connection (or other wireless methods). The main purpose of a loudspeaker is to act as a transducer that converts electrical energy (audio signals) into mechanical wave energy (sound waves). This is true regardless of if the speaker is wired or wireless.

The Bluetooth speaker takes in the wireless signal and converts it into sounds in addition to the Bluetooth worlds on a fixed frequency which is around 2.4 GHz and the data transmitted is called digital data. Digital data is transmitted wirelessly to the speaker protocol, so adding on digital data is not prone to interference. Every device emits electrical interference and this can enter into the audio wireless connection. Not to mention they can mess up the audio signal in the wires. On

the inside, the conversion is carried out through a DAC ( which is a digital to analog converter). The audio signals are analog.

Analog signals have an infinite value and digital signals have only two values. This means that the audio signal is a log signal whereas the Bluetooth transition is a digital signal. The conversion of the Bluetooth transition audio is carried out by the data. Another device inside the Bluetooth speaker, the amplifier, is a special device that takes up power from the batteries and this creates and increases the sound because of its high energy. The amplified signal drives the speakers and the speaker produces the sound.

Conclusion

As technology advances so do everything around and the Bluetooth speaker is an invention that proves scientists correct. Society will keep developing as human civilization and objects will follow along. The Bluetooth was a creation that came from two different items, a speaker and Bluetooth itself, and with the help of Haartsen in 1994, a combination was made. The Bluetooth speaker allows humans to listen to their music in much higher audio than a telephone can. Using a traditional speaker or even recorder player would take up space with cords and records nevertheless the Bluetooth speaker not only saves time but it’s easier in the sense that you can connect from a mobile device and be feet away and still listen to the music.

References

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About Ericsson – Corporate information. (n.d.). Telefonaktiebolaget LM Ericsson. https://www.ericsson.com/en/about-us

(2022). Retrieved 13 April 2022, from https://thesassway.com/do-bluetooth-speakers-have-lithium-batteries/.

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Ferguson, A. (2022, January 5). Let There Be Sound: The Interesting History of Speakers. Decker & Sons. https://www.deckersons.com/blog/speaker-history

How Do Speakers Work: Understanding Audio Reproduction [Infographic]. LANDR Blog. (2022). Retrieved 13 April 2022, from https://blog.landr.com/how-do-speakers-work/.

How does a lithium-ion battery work?. Let’s Talk Science. (2022). Retrieved 13 April 2022, from https://letstalkscience.ca/educational-resources/stem-in-context/how-does-a-lithium-ion-b attery-work.

NIHF Inductee Jaap C. Haartsen Invented Bluetooth Wireless Technology. (2022, March 28). National Inventors Hall Of Fame. https://www.invent.org/inductees/jaap-c-haartsen

Triggs, R. (2021, August 16). A little history of Bluetooth. Android Authority. https://www.androidauthority.com/history-bluetooth-explained-846345/

Udanis, A. (2019, June 7). Teardown Tuesday: What’s Inside a Bluetooth Speaker? News. https://www.allaboutcircuits.com/news/teardown-tuesday-whats-inside-of-a-bluetooth-sp eaker/

What is a Speaker – javatpoint. (n.d.). Www.Javatpoint.Com. https://www.javatpoint.com/what-is-a-speaker

What You Really Need to Know About Bluetooth Audio. Wirecutter: Reviews for the Real World. (2022). Retrieved 13 April 2022, from https://www.nytimes.com/wirecutter/blog/what-you-need-to-know-about-bluetooth-audio /.