Use this glossary for quick, plain-English definitions of the pitch, tuning, voice, and digital-audio terms used across PitchDetector.com.
For deeper explanations and structured learning paths, visit the Pitch Detection Knowledge Hub. For information about how PitchDetector.com interprets pitch-analysis results, see our Methodology.
Pitch & Frequency
Pitch
Pitch is the perceived highness or lowness of a sound.
For many periodic musical sounds, pitch is closely related to fundamental frequency, but pitch and frequency are not exactly the same thing. Frequency is a physical measurement, while pitch is a perceptual property of sound.
Frequency
Frequency is the number of repeating cycles that occur each second.
It is measured in hertz (Hz).
For example, a periodic signal repeating 440 times per second has a frequency of 440 Hz.
Fundamental Frequency
Fundamental frequency, often written as F₀, is the repetition rate associated with a periodic sound and is often closely related to its perceived pitch.
It should not always be described simply as the “lowest frequency present,” because complex sounds can still imply a fundamental even when that frequency component is weak or absent.
Partial
A partial is an individual frequency component within a complex sound.
The fundamental can be one partial, while other partials may occur above it.
Some partials are harmonically related to the fundamental and some may be inharmonic.
Harmonic
A harmonic is a frequency component whose frequency is an integer multiple of a fundamental frequency.
If a fundamental is 200 Hz, an ideal harmonic series may include:
- 200 Hz — first harmonic;
- 400 Hz — second harmonic;
- 600 Hz — third harmonic;
- 800 Hz — fourth harmonic.
Strong harmonics are one reason pitch detectors can occasionally select the wrong octave.
Overtone
An overtone is any partial above the fundamental.
The terminology is related to harmonics but not identical:
- the first harmonic is the fundamental;
- the first overtone is the first partial above the fundamental, often the second harmonic in a harmonic series.
Octave
An octave is the musical interval associated with a 2:1 frequency ratio.
Moving up one octave doubles frequency.
For example:
- A3 ≈ 220 Hz;
- A4 = 440 Hz;
- A5 ≈ 880 Hz.
Moving down one octave halves frequency.
Octave Error
An octave error occurs when a pitch-estimation system selects a harmonic or subharmonic instead of the intended fundamental, causing the displayed result to appear an octave or more above or below the expected note.
Octave errors are more likely with strong harmonics, weak fundamentals, noise, and complex signals.
Notes, Tuning & Intonation
Musical Note
A musical note is a named pitch position within a musical system, such as C4, F♯3, or A4.
The same note name can occur in multiple octaves at different frequencies.
Cents
A cent is a logarithmic unit used to measure musical intervals and small pitch differences.
In 12-tone equal temperament:
100 cents = 1 semitone
Pitch tools often use cents to show how far a detected pitch is above or below a reference note.
Pitch Deviation
Pitch deviation is the difference between a detected or measured pitch and a target or reference pitch.
It is often expressed in cents.
A negative value usually indicates a pitch below the reference, while a positive value indicates a pitch above it.
Semitone
A semitone is one-twelfth of an octave in 12-tone equal temperament.
Its ideal frequency ratio is:
2^(1/12)
or approximately 1.05946:1.
Intonation
Intonation describes how pitches are produced or tuned relative to an intended pitch system, reference, or musical context.
The term can apply to:
- singers;
- bowed strings;
- fretted instruments;
- wind instruments;
- ensembles;
- instrument setup.
Reference Pitch
A reference pitch is the chosen frequency assigned to a reference note for tuning.
A common example is:
A4 = 440 Hz
Other references such as A4 = 442 Hz may also be used.
A440
A440 means that the note A4 is assigned a frequency of 440 Hz.
It is a widely used tuning reference, but it is not the only reference used by orchestras, ensembles, historical-performance groups, or individual musicians.
Concert Pitch
Concert pitch is the shared tuning reference used by an ensemble or musical context.
It commonly refers to the chosen frequency for A4, but concert pitch does not always mean exactly 440 Hz.
Calibration
Calibration is the process of checking or adjusting a measurement system against a known reference.
Changing the selected A4 tuning reference from 440 Hz to 442 Hz is not necessarily calibration—it is usually a change of reference pitch.
Equal Temperament
12-tone equal temperament divides the octave into 12 equal logarithmic steps.
Each semitone has the same frequency ratio, which allows music to be transposed between keys without changing the size of the tempered intervals.
Just Intonation
Just intonation is a tuning approach that uses intervals based on simple whole-number frequency ratios.
It can produce highly consonant intervals in appropriate contexts, but the exact tuning relationships depend on the tonal framework being used.
Meantone Temperament
Meantone temperament refers to a family of tuning systems that narrow certain fifths in order to improve the tuning of major thirds.
Different meantone systems distribute tuning differences differently and can make some keys more usable than others.
Well Temperament
Well temperament refers to a family of unequal temperaments designed so that all keys can be used while different keys retain different interval characteristics.
It is distinct from modern equal temperament.
Pitch Detection & Algorithms
Pitch Detection
Pitch detection is the process of estimating the pitch or fundamental-frequency candidate of an audio signal.
The result can then be mapped to information such as:
- note name;
- octave;
- frequency;
- cents deviation.
Pitch Tracking
Pitch tracking means making repeated pitch estimates over time so that changes in pitch can be followed as a contour.
It is useful for studying:
- glides;
- vibrato;
- sustained vocal notes;
- melodic movement.
Pitch Confidence
Pitch confidence is a value indicating how strongly an algorithm supports its current pitch candidate according to its internal scoring method.
It is not the same as a guaranteed percentage of accuracy.
A detector can still be confident in a harmonic or wrong octave under difficult signal conditions.
FFT
FFT stands for Fast Fourier Transform.
It is an efficient algorithm for computing the frequency-domain representation of a sampled signal.
An FFT can show how signal energy is distributed across frequencies and may be used as part of some pitch-analysis methods, but it is not automatically a complete pitch detector by itself.
Autocorrelation
Autocorrelation is a signal-processing technique that compares a waveform with delayed versions of itself.
Repeating patterns can help estimate the period of a signal, which can then be related to fundamental frequency.
YIN
YIN is a fundamental-frequency estimation algorithm based on a difference function and additional processing steps intended to improve pitch-period selection and reduce certain common errors.
YIN is one method used in the wider field of pitch estimation.
Its inclusion in this glossary does not mean every PitchDetector.com tool necessarily uses YIN in production.
Machine-Learning Pitch Estimation
Machine-learning pitch estimation uses trained models to infer pitch from audio.
Examples from the wider field include systems such as CREPE and SPICE.
These are examples of research and implementation approaches and should not be assumed to represent PitchDetector.com’s production algorithm unless explicitly stated.
Monophonic
A monophonic signal contains one primary note or pitch at a time.
Many basic pitch detectors work best with monophonic input.
Examples include:
- one sung note;
- one guitar string;
- one flute note;
- one tuning-fork tone.
Polyphonic
A polyphonic signal contains multiple simultaneous notes.
Examples include:
- chords;
- choir harmony;
- piano accompaniment;
- full music mixes.
Single-pitch detectors can become unstable when several strong pitches are present at once.
Sound & Voice
Timbre
Timbre is the perceptual character that helps distinguish sounds even when they have similar pitch and loudness.
It is influenced by characteristics such as:
- frequency spectrum;
- harmonics;
- transients;
- envelope;
- noise components;
- changes over time.
Vibrato
Vibrato is a periodic variation in pitch used in many vocal and instrumental styles.
It can be described by:
- rate — how quickly the pitch cycles;
- depth — how far the pitch moves, often expressed in cents.
A live detector may show the cents value moving during vibrato.
Formant
A formant is a resonance of an acoustic system.
Formants are especially important in speech and singing because resonances of the vocal tract strongly influence vowel quality and timbre.
A formant is not the same thing as the fundamental frequency of the voice.
Signal-to-Noise Ratio
Signal-to-noise ratio, or SNR, compares the level of the desired signal with the level of unwanted background noise.
A cleaner signal with a stronger SNR generally gives a pitch detector more useful information to analyze.
Noise Floor
The noise floor is the background signal level produced by a recording system, microphone, electronics, environment, or combination of sources.
If the desired note is too close to the noise floor, stable pitch estimation can become more difficult.
Clipping
Clipping is distortion that occurs when an audio signal exceeds the level a recording or processing system can represent cleanly.
Clipping changes the waveform and can introduce additional harmonics, making pitch analysis less reliable.
Digital Audio
Sample Rate
Sample rate is the number of audio samples captured or processed each second.
Common examples include:
- 44.1 kHz;
- 48 kHz;
- 96 kHz.
Sample rate affects digital-audio bandwidth and processing constraints, but a higher sample rate does not automatically mean more accurate pitch detection.
Pitch-estimation performance also depends on the algorithm, signal quality, window length, interpolation, preprocessing, and pitch range.
Bit Depth
Bit depth describes the number of possible amplitude values available for each sample in PCM digital audio.
It is related to:
- quantization resolution;
- theoretical dynamic range.
A higher bit depth does not by itself guarantee better pitch estimation.
Buffer Size
Buffer size refers to the amount of audio processed in each block or chunk.
Smaller buffers can reduce latency but may increase processing overhead.
Larger buffers may improve stability in some systems but can increase delay.
Latency
Latency is the delay between an audio event and the corresponding processed or displayed result.
In browser audio, latency can come from:
- audio capture;
- buffering;
- processing;
- device routing;
- display updates.
Frequency Spectrum
A frequency spectrum represents how a signal’s energy or amplitude is distributed across frequency.
It helps show which frequency components are present in a sound.
A spectrum is different from pitch: a complex sound can contain many spectral components while still being perceived as one pitch.
Spectrogram
A spectrogram is a visual representation of how the frequency content of a signal changes over time.
It commonly displays:
- time on one axis;
- frequency on another;
- intensity through visual strength or shading.
You can explore this type of representation with the Spectrogram Viewer.
Web Audio API
The Web Audio API is a browser technology for processing, routing, generating, and analyzing audio.
It can work with audio streams obtained through browser media APIs and is commonly used for interactive browser-based audio applications.
For the official browser documentation, see the MDN Web Audio API reference.
AudioContext
An AudioContext is the main processing environment used by the Web Audio API.
It manages connected audio nodes used for operations such as:
- input;
- analysis;
- filtering;
- routing;
- output.
Browser rules can affect when an AudioContext is allowed to start, particularly around user interaction and media permissions.
Practical Pitch-Tool Terms
Sharp
A pitch is sharp when it is above the intended or reference pitch.
Pitch tools commonly display this as a positive cents deviation.
Flat
A pitch is flat when it is below the intended or reference pitch.
Pitch tools commonly display this as a negative cents deviation.
In Tune
In tune generally means that a produced pitch is sufficiently close to the intended tuning reference for the musical context.
It does not require a mathematically perfect zero-cent reading at every instant, especially with naturally varying sounds such as voice or bowed strings.
Stable Pitch
A stable pitch is a pitch that remains relatively consistent over a period of time.
Stable sustained input is generally easier for a detector to analyze than rapidly changing, noisy, or strongly modulated input.
Signal Quality
Signal quality describes how suitable the incoming audio is for analysis.
A useful signal is typically:
- strong enough to detect;
- not clipped;
- relatively clean;
- dominated by the intended sound.
Signal quality is not the same as pitch accuracy, but poor signal quality can make reliable analysis harder.
Target Note
A target note is the note a musician intends to sing, play, or match.
Pitch-practice tools can compare the produced pitch with that target and display the difference.
Tuning Deviation
Tuning deviation is the difference between an observed pitch and the chosen tuning reference or target note.
It is commonly shown in cents.
Learn Beyond the Definitions
Use this glossary when you need a quick definition.
For deeper explanations, practical workflows, and structured topic paths, continue with the Pitch Detection Knowledge Hub.
If you want to understand why a detector may jump between notes, select the wrong octave, or behave differently with various sounds, see our Methodology and Pitch Detector Troubleshooting pages.
For questions or corrections, contact support@pitchdetector.com or visit Contact Us.
Last reviewed: August 19, 2026