Is a Microphone Input or Output Device?

Microphones are input devices that send audio signals into the computer through an audio interface or analog-digital converter. However, some digital mics act as input-output devices with their built-in headphone amps, which additionally get an audio signal from computer.

People often get confused with the fact what is an input and output device. The short answer for the question of whether a microphone is an input or output device is simple, most of the microphones are input devices. 

However, to understand why, as well as the fact that some microphones are input/output devices, it is necessary to define what input and output devices are in the first place.

What is an audio input device?

If we take into account a computer system, an input device would be the one that sends or inputs information to the system to record, process audio, or gives commands to the system. Microphones and MIDI keyboards are the most common types of audio input devices.

Microphones convert sound waves into audio signals, which are converted into digital audio data and sent to computers, and are therefore considered input devices. In order to truly qualify as an input device, microphones must output AC voltages (analog audio signals), and only after they are converted to digital data can they transmit the information.

Analog signals need a bridge in between to be converted to digital signals. The bridge can be a hub type or an adapter type audio interface. Another way is to use digital microphones, which are equipped with built-in analog to digital converters.

So, there will be an ADC (analog to digital converter) in action in any case: it could be through an audio interface that can be a hub or an adapter or directly from a digital microphone with an internal ADC that gets connected via USB to the computer. In the case of digital microphones, the signal leaves the mic body already converted into digital data.

To summarize, if you consider a microphone in relation to a computer system, it is an input device. But, its signals need to be converted to digital signals to truly become an input device. 

What is an audio output device?

On the contrary, audio output devices are the ones that receive digital audio signals and convert them into human-perceptible forms, which are the sound waves that we hear. To put it simply, any device that we hear audio from is actually an output device, like headphones and speakers.

Monitors, headphones, amplifiers, sound cards are output devices that receive audio signals from instruments, microphones, or any source like a computer or a smartphone and transform them into the desired format.

When you want to figure out if a device is an input or an output device, think in terms of a computer. If it is receiving audio signals, the signals are coming from an input device, like a microphone or a MIDI instrument. If it is sending out audio signals like playing music, a podcast, or any kind of audio, the device the signals go out through, like a speaker or headphones, are the output devices.

Microphones As An Input And Output Device 

Coming back to the mics, if you consider a microphone beyond its intended usage purpose, it could be used as an output device. You can actually force the direction of the signal to the opposite direction, basically using the microphone as a speaker. Unfortunately, this attempt could ruin your microphone, as receiving audio signals is not their purpose.

As mentioned before, digital mics with built-in headphone amps act both as an input and output device. Their main purpose is to input analog audio signals to the digital signals in a computer or recording device, but the built-in amp acts as an output device.

Lastly, if we consider headphones that come with microphones, we could define them as both input and output devices. These microphones send audio signals to the data as an input device, but the headphones receive audio signals from the computer or smart device, making them an output device.

Conclusion

Microphones are input devices that receive analog audio signals and send them into computers, smartphones, or any device. On the way, these analog signals are converted into digital signals by an ADC (analog to digital converter) like an audio interface to be understood by the target device.