What Are Speakers?

Date First Published: 3rd July 2023

Topic: Computer Systems

Subtopic: Computer Hardware

Article Type: Computer Terms & Definitions

Difficulty: Easy

Difficulty Level: 2/10

CONTENTS

How Do Speakers Work?
Difference Between External and Internal Speakers
Sound Quality Indicators

Learn about what speakers are in this article.

Speakers are output devices used by computers to generate sound that can be heard by the listener. They are most commonly used to listen to music and take part in VoIP conversations. Some speakers are only designed to work with specific computers, whilst others can work with any type of sound system.

Speakers almost always come in pairs which allows them to produce stereo sound. This means that the left and right speakers transmit audio on two different channels. This makes audio sounds more natural because most people's ears are used to hearing sounds from both the left and right sides at the same time. Sometimes, surround systems may include 4-7 speakers.

How Do Speakers Work?

Speakers work by converting electromagnetic waves into sound waves. The speakers receive a digital audio signal from a computer and convert it into an analogue signal. The analogue electronic waves are then amplified into sound waves that can be heard by the listener. Since sound waves are always produced in analogue form, digital speakers need to convert the digital input into an analogue signal before generating the sound waves.

Difference Between External and Internal Speakers

Speakers can be external or internal. External speakers connect to a computer by a cable or a Bluetooth connection and have a power source, like an AC adapter or batteries. The signal input connector is often a 3.5 mm jack plug, an RCA connector, or a USB port to supply both signal and power. Portable devices, including laptops, smartphones, and tablets have built-in speakers. However, external speakers can be connected to those devices if louder sound or surround sound is needed. Connecting external speakers to those devices will disable the built-in speakers. Sometimes, computer monitors may have integrated speakers.

Sound Quality Indicators

Below are indicators that can be used to measure the sound quality of speakers:

Frequency response - The range of frequencies that a speaker can produce. The frequency determines the pitch of the sound and how high or low it is. The capability of a speaker to accurately produce sound frequencies is a good indicator of how clear the audio will be.
Signal-to-noise ratio - The ratio of signal levels to the background noise, expressed in decibels (DB). When turning a speaker on, certain audio signals are sent to it. The signals are converted into sound waves, but that sound does also come with a certain amount of background noise. The larger the number, the better.
Sensitivity - A measure of the ability of the speaker to convert electrical signals into sound waves, expressed in decibels of sound pressure level per milliwatt. This indicates how much volume will be received within a given amount of power.
Impedance - The resistance of the speaker to the electrical current, measured in Ohms (Ω). The lower the impedance, the more easily electrical currents (the signal or music) flow through the speaker, but a too-low impedance will require more current than the amp has to offer, which will cause it to be constantly overpowered.
Total harmonic distortion - Measures the distortion level of the audio signal received by the speaker from the source device. It is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency.