Glossary
Noise-canceling microphone
A noise-canceling microphone is designed to filter ambient noise, so it picks up mainly the speaker's voice. It can help dictation in noisy rooms, but it does not remove all noise, and it is different from the active noise cancellation in headphones.
Updated October 16, 20265 cited facts, each traced to its source
Also called noise-cancelling microphone, noise-canceling headset.
A noise-canceling microphone is a microphone designed to filter ambient noise 1. It is built so that the voice close to its mouth opening is picked up more strongly than sound from across the room. The spelling "noise-cancelling" is also common, and a "noise-canceling headset" is the same idea in a headset.
The microphone uses two sound ports to favor near sound
Most of these microphones use a differential design. All such microphones have at least two ports through which sound enters: a front port normally oriented toward the desired sound, and a port that is more distant 2. Sound from far away reaches both ports about equally, so it moves the diaphragm very little. A mouth close to the front port creates a larger pressure difference, so the voice moves the diaphragm far more.
That is the whole mechanism. The microphone does not identify the words. It favors the sound that is close to it, which is usually the speaker.
Background noise hurts recognition more than people expect
Speech recognition is sensitive to noise. A 1996 study says that the performance of a speech recognition system degrades rapidly in the presence of ambient noise 3. That study used an early system and a small vocabulary, so it shows the direction of the effect rather than today's error rate.
A 2004 study of an oral-history archive, with noisy, elderly and accented speech, found that signal-to-noise ratio and syllable rate were the two dominant factors explaining the overall word error rate 4. A noise-canceling microphone raises the signal relative to the noise, which is the lever that study points to. The ranking of factors is the finding there, not the absolute error rate.
Apple advises a headset microphone in noisy rooms
Apple's own guidance for dictation on a Mac says that if you use Dictation in a noisy environment or a room with excessive echo, it may help to use a headset microphone 5. The wording is "may help", and Apple gives no measured accuracy figures for it. Treat it as a sensible starting point, then test your own room.
What a noise-canceling microphone does not do
A noise-canceling microphone reduces noise that comes from a distance. It does not remove a loud voice in the next seat, and it does not fix a room with heavy echo on its own. Our guide to dictation and background noise covers where to dictate and how to set up a quiet spot. The microphone guide compares the options.
Do not confuse this with active noise cancellation in headphones. Headphones with active noise cancellation reduce what you hear. That is a different feature from a microphone that rejects room sound, so check the microphone specification when you choose a headset for dictation.
Why it matters for dictation
Dictation accuracy depends on the signal the recognizer receives. A microphone close to the mouth, with a design that favors near sound, gives the software a cleaner signal to work with. That matters most in offices, clinics and shared spaces, where the room is not quiet. For a broader view, read our guide to dictation mistakes.
Related terms
- Dictation: speaking so that your words are written as you say them.
- Voice typing: live speech-to-text inside an app.
- Voice writing: a method that keeps the writer's voice out of the room.
Evidence
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Related terms
- Dictation and Voice Typing: How to Talk Instead of TypeThe topic this term belongs to
- Automatic punctuationAutomatic punctuation is when speech software infers commas, periods and question marks from your speech and inserts them without a spoken command. It can be switched on or off, and it works only in supported languages.
- DictaphoneA Dictaphone is a machine that records a speaker's voice so that another person can play it back and type it later. The name began as a brand, and it became the everyday word for dictation machines.
- DictationDictation is speaking your words so that software writes them as text, usually into the app that has the cursor. Phones and computers now include it, and people also call it voice dictation or voice typing.
- Dictation foot pedalA dictation foot pedal is a footswitch that controls playback of a recording, so a typist can start, pause and rewind audio without using their hands. It is the traditional control for transcribing dictation.
- Digital dictationDigital dictation is recording speech as digital audio, then sending the file to a typist or to speech recognition software for transcription. It replaced tape with files that can be encrypted, uploaded or routed for processing.
- Filler wordsFiller words are sounds and words such as um, uh, like and you know that speakers produce while they plan what to say next, without adding content. Many dictation tools can remove them automatically, and research on transcripts found they can be deleted without compromising meaning.
- HomophoneA homophone is a word pronounced the same as another word but different in meaning, spelling or both, such as to, too and two. Dictation software has to choose the right spelling from context, so homophones are one of the most common errors in dictated text.
- Oral compositionOral composition is working out and shaping a text by speaking it, whether to a dictation tool, to a recorder or silently in thought. Research on letters finds that planning takes most of the time, however the text is produced, so speaking mainly changes how the words get onto the page.
- Push-to-talkPush-to-talk is a dictation mode in which you hold a key while you speak and release it to stop, so the software writes only the speech made while the key is down. Some tools also offer tap-to-start and tap-to-stop.
- ShorthandShorthand is an abbreviated symbolic writing method that increases the speed of writing compared with longhand. Trained writers used it to take dictation before recording machines, and it still underpins court reporting.
- Spoken punctuationSpoken punctuation is saying the name of a punctuation mark, such as comma or question mark, so that dictation software writes that mark into the text. It is the manual alternative to automatic punctuation.
- Voice commandA voice command is a spoken instruction that the software carries out, such as delete or stop listening, rather than writing the words as text. Dictation tools must separate commands from dictated words, and the rules differ by product.
Pages that use this term
- Dictation and Voice Typing: How to Talk Instead of TypeTopic
- Writing a Book by Dictation: Software and WorkflowGuide
- Dictation Not Working? How to Fix It on Any DeviceGuide
- Dictation Mistakes and How to Make Voice Typing AccurateGuide
- Best Microphone for Dictation: What Actually MattersGuide
- Dictation and Background Noise: Where and How to DictateGuide
- Can you dictate in a noisy room?Question
- Can you use dictation in an open-plan office?Question
- How do you transcribe low-quality or quiet audio?Question
- What is the best microphone for medical dictation?Question
- Voice writingGlossary