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What is External Speaker?
External speaker refers to an output hardware connected to the computer or any sound source to produce sound. In computers, however, the signals required to produce the sound are created by the sound card of the computer system.
Technically speaking, the external speakers create a magnetic field that is interchanged by the audio signals. This moves the voice coils and the diaphragm to create local pressure and produce sound.
- Using external speakers will enable you to hear sounds from a desktop computer, which usually does not have any built-in speakers.
- External speakers are also necessary to improve the sound output of laptop computers.
- It is very easy to connect and use these additional speakers, whether they come with a 3.5 mm audio jack or a USB connector.
- You can use different types of external speakers of different ratings according to your wish.
Understanding External Speaker
The external speakers improve the audio quality by using an internal amplifier.
Apart from computers, these speakers can be used with different audio sources, such as an MP3 player.
An external speaker usually needs a power source to operate, which can be provided from the main power supply through an AC adapter, a USB port, or even batteries.
Depending on the design of the speakers, signals can be transferred through a 3.5 mm jack plug, a Radio Corporation of America or RCA connector, or a USB port.
Out of these, a USB port is usually used in computers these days, which can supply both power and signal, but needs additional circuitry.
The battery powered devices are usually wireless Bluetooth speakers. They do not need any connections at all.
Usually, when you connect an external speaker to a computer, it will automatically disable the built-in speaker of that computer, if there is any in the first place.
There are different types of external speakers available for use. Some are small in size, while others are large and heavy.
The build may also be different as the features, depending on the brand and price of the speaker system.
Additional features include:
- Bass and treble controls
- A subwoofer and more.
The desktop computers usually do not have any speakers built in to produce sounds, but the laptop computers do.
However, the sound quality is quite poor in the laptop computers due to the smaller and limited features.
Talking about computers, the initial models had speakers onboard to produce sounds limited to beeps and tones.
Later on, in 1981, IBM designed the first computer with internal speakers. It, however, produced just basic and very low quality sound.
Over time, the speakers were built in the computer monitor, located at the bottom left and right front of it usually.
These speakers could produce music, voices and other sound effects.
Still, it was not enough for high-quality output, which is why external speakers are needed while playing games, listening to digital music, and consuming other media.
These speakers produce high quality sound with deeper bass.
Depending on the performance of these speakers, they are rated differently based on different other parameters as well, such as:
- The Total Harmonic Distortion or THD, which is the quantum of distortion created when a signal is amplified
- The frequency response, which is the measurement of the highs and lows of the sound produced by the speaker and
- The Watt, which is the available amount of amplification for the speakers.
Working Principle of External Speakers
The external speakers mainly function as transducers. This is the phenomenon in which sound is produced by converting the digital audio from the source to analog audio by using a Digital to Analog Converter to produce perceptible sound waves. This is then emitted through the speakers.
Typically, sound is produced by the speaker’s electromagnetic drivers. These drivers vibrate accordingly to produce sound.
Therefore, there are actually two basic components that make the external speakers work. These are:
- The speaker drivers and
- The Digital to Analog Converters or DACs.
Ideally, the transducers, or drivers, are the most critical and main functional part of the anatomy of the speakers.
They convert electrical energy or audio signals into mechanical energy or sound waves.
The external speakers, like all other speakers, also use specific types of drivers, also known as electro dynamic drivers. The term ‘dynamic’ here refers to the moving coil in them.
These drivers use electromagnetic induction for the conversion process of the audio signals.
They also follow the principles of frequency response and size to determine the audible frequency range based on the range of human beings.
Universally, this range is 20 Hz to 20,000 Hz, but it is quite difficult for a typical electro-dynamic driver to cover this whole range.
That is why a variety of drivers are used in the speaker systems.
These are called the subtypes of electro-dynamic drivers, and a few examples of these would be:
- A subwoofer – This handles the low frequencies, ranging from 20 Hz to about 120 Hz. They usually have a large single driver along with a dedicated amplifier.
- A woofer – This covers low- to mid-range frequencies.
- A mid-range driver – This covers the mid-range frequencies.
- And a tweeter – This covers the high range of frequencies.
There is a crossover in the speakers to filter the incoming signals effectively and direct them to the appropriate drivers in the correct frequency bands.
Now, the Digital to Analog Converters read the digital representation and change it into an analog electrical AC audio signal.
These are continuous waveforms containing both high and low voltage, and the frequency ranges between the audible range of 20 Hz and 20,000 Hz, and often beyond.
The digital audio signals are however distinct waveforms. These waveforms are given amplitude values after being sampled more than a few times.
This is done on the basis of the sample rate and the bit depth, or the possible amplitude values.
For the external speakers, the sample rates per second include:
- 1 KHz
- 48 KHz
- 2 KHz and
- 96 KHz.
And the usual bit depths include 16 bits, or 65,536 possible amplitudes, and 24 bits, or 16,777,216 possible amplitudes.
The DAC reads all these digital audio signals based on each sample and then decodes all the available information in them to produce a continuous and smooth analog signal.
These electro-dynamic external speakers have different components that work in unison to make them work, such as:
- Diaphragm – This membrane moves back and forth based on the audio waveform, pushing the air to produce sound
- Cone – This is a membrane in the voice coil that moves in and out
- Dust cap or dome – This protects the cone from dust and debris
- Suspension – This connects the diaphragm and the speaker housing to allow proper diaphragm excursion or Z-axis by restricting the motion in X and Y axes
- Surround – This ring-shaped component determines the limit of the diaphragm excursion and reduces resonance by absorbing energy
- Spider – This inner part of the suspension holds the voice coil in place when it moves
- Voice coil – This is a tightly wound, cylindrical coil of conductive wires with the lead wire connected to the two ends to form a circuit for the AC audio signal to pass
- Magnetic structure – This provides a permanent and concentrated magnetic field in the voice coil and the driver
- Magnet – This is the source of the magnetic field
- Top pole plate – This extends one pole of the magnet to the voice coil exterior
- Yoke – This is the bottom pole plate and pole piece at the back that extends the other pole of the magnet to the voice coil interior and
- Basket – This is the physical housing.
The AC audio signal goes through the voice coil to enter the magnetic field and create an alternate magnetic field.
It then intermingles with the permanent magnetic field, which is created by the magnet of the driver.
The voice coil is attracted and repulsed when the magnetic field alternates, causing it to oscillate and imitate the waveform of the audio signal.
The diaphragm moves with the voice coil as per the audio signal to increase and decrease local pressure and transmits outward to produce eventual sound waves.
How to Connect External Speakers to a Computer?
Whether it is a set of external headphones or a set of USB speakers, you will need to connect it to the computer by inserting the speaker connector into the appropriate port of the computer, depending on the type. In most cases, the computer will recognize the device automatically.
Additionally, be informed that there is no need for a driver to connect the external speakers to your computer system.
If you find that the speakers are not working after connecting, consider that there are issues with the sound card and that you may need to install a driver.
And you do not need to switch off the computer system to connect or disconnect your speakers.
It can be done when the system is on and running. The operating system will show when a speaker is connected to or disconnected from it in a small pop-up window.
There are different methods for connecting a set of external speakers to a computer system.
If it is a speaker set or headphones with a 3.5 mm jack, here is all that you need to do. Connect the 3.5 mm jack coming out of the ‘main’ speaker (usually the one with the volume knob) to the audio output jack of the computer.
Switch the speaker on, and it is ready to go.
Sometimes, there may be some additional connectivity requirements depending on the model of the speaker.
For example, there may be a mini plug that is to be connected to the audio line level output, generally colored lime green, at the back of the computer.
And, if you are using multichannel speakers, such as 5.1 and 7.1 channel speaker systems, you may need to use some additional connections provided by the motherboard, which include:
- CS-Out, or center/subwoofer speaker
- RS-Out, or rear surround sound line out and
- SS-Out, or side surround sound speaker.
If your speaker system comes with USB connectivity, simply insert it into a USB port on the computer system.
And, if your speakers come with a subwoofer, the right speaker should be plugged into the subwoofer.
In laptop computers, you may not find any specific sound port. In that case, you will need to insert the mini plug of the speaker into the headphones port of the laptop.
After completing the connection, if you need to adjust the volume, you can use the volume knob or control of the speaker system as well as the sound or video bar, usually located at the right-hand corner of the taskbar.
If your computer has Bluetooth connectivity, you can use a set of Bluetooth speakers, but you will have to pair both devices first to get the audio output.
The steps to follow to connect such external speakers to a Windows 10 computer, after making sure that your Bluetooth set is on and is set in the Bluetooth mode, are:
- Opening computer settings
- Clicking on Device, which will typically show Bluetooth, printers, mouse
- Selecting the Bluetooth & other devices
- Sliding the Bluetooth button to ON
- Pairing your Bluetooth speaker by clicking on your speaker model when displayed in the list of discoverable devices available and
- Clicking on Connect.
This will route the audio from the computer to the Bluetooth speaker.
You may need to refer to the manual of your speaker system because the pairing methods may slightly vary from one model to another.
How to Make a Computer Recognize External Speakers?
If the computer does not recognize the external set of speakers connected to it, the playback devices should be set as the default device. This can be done from the speaker or volume icon.
You can do it by following these specific steps:
- Click on the speaker or volume icon on the system tray
- Right click on it to open the Sound menu
- Choose Playback Devices
- Right-click on the window background
- Choose Show Disabled Devices to see all speakers and sound cards connected to the computer system
- Click on the name or model of the speaker
- Select Set as Default
- Click on Apply and Ok.
However, as said earlier, usually, there is no need to worry about the computer recognizing the external speakers when connected, as it will be done automatically.
Why Use External Speakers?
Quite obviously, you will need to use external speakers to hear sounds from your computer, especially from a desktop computer, which typically does not come with any speakers built in.
The laptop computers do come with built-in speakers, but those are usually of very low output. External speakers are needed to enhance the audio quality and experience.
A set of external speakers can be a very useful appendage to a computer system, especially if you make video calls often, listen to music, or play games.
It will surely enhance your listening pleasure by enhancing the sound quality and output of a laptop, which a desktop does not have in the first place.