In almost all instances, speakers are output devices. They are generally connected to an amplifier or a device such as a computer or other equipment with an analog or digital signal. These resulting electromagnetic waves are converted into sound waves for easy listening.
What is an input device?
Anything that puts signal or information into the system is an input device. Again, some will be digital, and some analog. Digital inputs include computers, smartphones, tablets, and other devices. A microphone or turntable are examples of analog inputs. In this instance, an ADC (analog-to-digital) converter is necessary.
What is an output device?
These devices take the information or signal from the sound system or computer and convert it to a sound that we can hear or, in the case of screens and monitors, an image we can see. If the outgoing signal is digital and you want to play it on traditional speakers which are analog, then you will need a DAC (digital-to-analog) converter.
The amplifier will take the incoming audio signal and make it louder so that you can enjoy the sound from the speakers at a good volume.
A speaker, monitor, printer, and projector are all examples of output devices.
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Can a speaker be an input device?
Yes, there are instances where a speaker can perform as both an output as well as an input device. An example is when multiple speakers are connected in a daisy-chain format. This means that the speakers in the chain are both regular output devices but also function as input devices. This is often seen with Bluetooth speakers but the same concept can apply to traditional wired speakers.
Here you can learn more about How to Connect Multiple Bluetooth Speakers.
Some speakers also have an output for a subwoofer. This will increase the bass frequency for rich deep sound.
Passive and Active Speakers
Another issue that may confuse some readers is active and passive speakers. Most home speakers are passive meaning that they receive a signal that has already been amplified. Active speakers have an integrated amplifier
Input and output are usually computer terms but apply to audio equipment in much the same way. It is all in the name. Input is something going in and out is something coming out. It is as simple as that. Speakers are therefore output devices in most systems. There are cases, as explained above, where a speaker can be both an input as well as an output device.