Audio output devices convert electrical signals into sound waves that can be heard by humans. They allow computers, smartphones, music players and other electronic devices to produce audio that is meant to be listened to. There are several common types of audio output devices used in consumer electronics and computing.
Speakers
Speakers are one of the most common audio output devices. They contain a permanent magnet and a coil. When an electrical audio signal passes through the coil, it creates a varying electromagnetic field that causes the permanent magnet and attached speaker cone to vibrate back and forth rapidly. This pushes on the air to create sound waves that travel to the listener’s ears.
Speakers come in many sizes and designs for different purposes. Large standalone speakers are used for home stereo systems and events. Smaller built-in speakers are embedded in devices like laptops, smartphones and televisions to produce sound. Headphones and earbuds are speakers small enough to wear over or in the ear.
Types of Speakers
There are several common speaker types and designs:
- Woofers – Handle low frequency bass sounds
- Tweeters – Produce high frequency treble sounds
- Subwoofers – Specialized for very low bass frequencies
- Full range – Able to produce a wide range of frequencies
- Surround sound – Multiple speakers placed around a room to create an immersive listening experience
Headphones
Headphones are audio output devices worn over or in the ear. They have small speaker drivers in each ear cup or bud that convert an electrical signal into soundwaves next to the listener’s ears. Headphones allow you to listen to audio content without disturbing others and enable private listening in public places.
Common types of headphones include:
- Over-ear headphones – Completely enclose the ears with padded cups
- On-ear headphones – Rest on the ears with smaller pads
- Earbuds – Fit inside the ear canal
- Noise cancelling headphones – Electronically counteract ambient noise
- Wireless headphones – Connect wirelessly via Bluetooth
Home Theater Systems
Home theater systems use multiple speakers strategically placed around a room to create a cinematic audio experience. The most common setup includes front left, center and right speakers, rear surround speakers and a subwoofer. The audio signal is split into multiple channels that are fed to each speaker to produce an immersive surround sound effect.
Common Home Theater Speaker Types
- Front left and right – On either side of TV/screen
- Center channel – Above or below screen for dialogue
- Surrounds – On side and rear walls
- Subwoofer – Provides powerful low frequency bass
Home theater receivers decode multi-channel audio formats like Dolby Digital and DTS and distribute the correct audio signals to each speaker.
Soundbars
Soundbars are slim speaker units designed to improve audio quality for televisions, while requiring less space than a full home theater system. They contain multiple specialized speakers in one long enclosure that is placed in front of or mounted below the TV screen. While soundbars cannot replicate full surround sound, higher-end models simulate surround effects using psychoacoustic processing.
Soundbar Speaker Types
- Tweeter – Produces high frequency sounds
- Mid-range driver – Handles middle frequencies like speech
- Subwoofer – Provides bass response
- Side-firing speakers – Bounce sound off walls to simulate surround
Soundbars are designed to be slim, discrete and simple to set up compared to home theater speaker systems.
Smart Speakers
Smart speakers like the Amazon Echo and Google Home contain built-in speakers for audio playback. They can stream music, podcasts, audiobooks and more from online services via WiFi and Bluetooth. Smart speakers utilize digital assistants like Alexa and Google Assistant for voice control activation.
Smart speakers typically have the following audio components:
- Tweeter – High frequency reproduction
- Mid-woofer – Handles mid to low frequencies
- Subwoofer – Provides bass response (on some models)
While smart speakers do not offer the best fidelity for music listening, their wireless connectivity, voice control features and compact form factor make them appealing for casual audio playback.
Sound Cards
A sound card is an internal computer component that enables audio output from a computer. It converts digital audio data into an analog electrical signal that can be amplified and sent to speakers or headphones. Sound cards allow desktop computers to play sound from games, media files, system alerts and more.
Common sound card ports and connectors include:
- 3.5mm analog jacks – For connecting headphones or speakers
- S/PDIF – Digital optical/coaxial audio output
- PCI/PCIe – Interface with motherboard
Higher quality sound cards can improve audio performance over basic integrated sound chips on the motherboard. Features like surround sound, high fidelity DACs and headphone amplification provide an enhanced listening experience.
Digital Audio Players
Portable digital audio players are handheld devices designed primarily for listening to audio files. This includes digital music players like the Apple iPod and MP3 players. They store media files digitally and have a screen, controls and headphones jack for private music playback.
Digital audio players convert compressed digital audio files like MP3, FLAC and AAC to an analog signal that is amplified and sent to headphones. Better quality players have higher resolution DACs and audio amplifiers to produce higher fidelity sound.
Common Digital Audio Player Features
- Storage – Built-in flash memory and/or memory card slot
- Screen – Displays track info, albums, playback controls
- Playback controls – Navigate tracks and adjust volume
- Headphones jack – 3.5mm and sometimes 2.5mm or USB-C
- High resolution support – FLAC, ALAC, etc. on some models
While smartphones can also play digital audio, dedicated players offer longer battery life and are designed specifically for music playback.
Television Speakers
Televisions have built-in speakers to produce sound from TV programs, streaming content, video games and other sources. They allow the TV to playback audio without the need for an external speaker system.
A typical TV has two main speakers consisting of:
- Tweeter – High frequency reproduction
- Mid-woofer – Covers mid-range frequencies
Higher-end TVs may have more robust speaker systems with added drivers for better sound. However, TV speakers are limited in sound quality compared to a dedicated stereo or surround sound speaker system.
Car Audio Systems
Car audio systems allow music and other audio playback inside an automobile. Factory installed car stereos have built-in amplifiers and speaker outputs. Aftermarket car audio systems can include upgraded components like:
- Head unit – Radio receiver, media player, touchscreen display
- Amplifier – Boosts signal to speakers
- Subwoofer – Provides bass in the trunk/rear
- Component speakers – Individual speakers for optimized sound
In addition to traditional car speakers, some vehicles incorporate premium audio systems with strategic speaker placement for surround sound effects.
Conclusion
There are many different audio output devices used to turn electrical audio signals into audible sound for the listener. Speakers, headphones, home theater systems, soundbars, smart speakers, sound cards, and audio systems built into televisions and vehicles allow us to hear audio content from a wide variety of sources.
Understanding the different types of audio output devices and how they convert digital signals into sound waves is helpful for anyone working with audio equipment or setting up electronics for optimal sound. Each device has its own advantages and ideal uses depending on factors like audio quality, cost, form factor and connectivity options.
