Glossary of Studio Monitoring Terms

This glossary defines the terms used across studio monitoring, from monitor types and loudspeaker design to room acoustics, stereo imaging, phase and time behaviour, and measurement and DSP. The definitions are short and practical, and they match how the terms are used in the rest of this library. Use it as a reference while reading the other guides, or to settle the meaning of a term you have seen used loosely elsewhere. Terms are grouped by topic so related ideas sit together, and many link to a full article where the concept is explained in depth.

Monitor Types

Studio monitor: A loudspeaker built for accurate, low-distortion reproduction for production work, rather than for a pleasing sound.

Active monitor: A monitor with built-in amplification matched to its drivers, fed a line-level signal.

Passive monitor: A monitor with no internal amplifier, requiring a separate external power amplifier.

Nearfield monitor: A monitor for close listening, roughly 0.7 to 1.5 m, so the direct sound dominates over the room.

Midfield monitor: A larger monitor for greater listening distances in bigger, treated rooms.

Point source: A design radiating the full range from one point, either a single full-range driver or a coaxial.

Coaxial: A driver arrangement with the tweeter at the acoustic centre of the woofer, a point-source approach.

Two-way monitor: A monitor with separate woofer and tweeter and a crossover dividing the signal between them.

Loudspeaker Design

Driver: The component that converts an electrical signal into sound by moving a diaphragm. Woofers handle lows, tweeters handle highs.

Crossover: A filter that splits the signal by frequency and routes each band to the appropriate driver.

Sealed enclosure: A closed cabinet with no vent, giving a gentle low-frequency roll-off of about 12 dB per octave.

Ported (bass-reflex) enclosure: A cabinet with a tuned vent that extends low output near its tuning frequency, with a steeper roll-off below it.

Baffle: The front face of the cabinet that the drivers mount in, which shapes their output and directivity.

SPL: Sound pressure level, a measure of loudness in decibels. Maximum SPL describes how loud a monitor plays before distortion or limiting.

Distortion: Any change that makes the output an unfaithful copy of the input, such as added harmonics (harmonic distortion).

Room Acoustics

Wavelength: The physical length of one cycle of a wave: the speed of sound (about 343 m/s) divided by frequency.

Room mode (standing wave): A resonance where reflections between surfaces reinforce, creating fixed regions of strong and weak bass.

Node and antinode: A node is a pressure minimum (weak bass), an antinode a pressure maximum (strong bass).

Schroeder frequency: The frequency above which modes overlap and the room behaves statistically. Higher in small rooms.

SBIR: Speaker-boundary interference response: low-frequency cancellation from a speaker's reflection off a nearby boundary.

Comb filtering: Regularly spaced peaks and dips from a sound combining with a delayed copy of itself.

First reflection point: The spot on a surface where sound first bounces toward the listener, worth treating to keep tone and imaging clear.

Decay time: How long sound takes to die away in a room. Shortened by absorption, unaffected by EQ.

Bass trap: A deep, dense low-frequency absorber, usually placed in corners where modal pressure is highest.

Imaging and Translation

Stereo imaging: The perceived position, width and depth of sounds across the space between the monitors.

Phantom image: A source that appears between the speakers where no speaker exists, created by matched level and timing in both channels.

Sweet spot: The symmetrical listening position where imaging and balance are most accurate.

Interaural level / time difference: The loudness and arrival-time differences between the ears that the brain uses to locate sound.

Mix translation: How well mix decisions made on one system carry over to other playback systems.

Mono compatibility: Whether a stereo mix keeps its balance and level when summed to mono.

Phase and Time

Phase: The position within a cycle of a sinusoidal component. Relative phase shapes composite waveforms.

Phase coherence: Preservation of the correct relative timing between frequency components as they are reproduced.

Time alignment: All of a speaker's output reaching the listener at the same instant.

Group delay: The frequency-dependent time delay through a system. Constant is benign, varying is phase distortion.

Impulse response: A system's output to an impulse, which fully characterises its magnitude and phase.

Minimum phase: A system whose phase is fixed by its magnitude, so EQ that fixes magnitude also fixes phase.

Linear phase: Equal delay for all frequencies, so magnitude can change without rotating phase. Adds latency and pre-ringing.

Pre-ringing: Energy appearing before a transient, a side effect of linear-phase FIR filters that can smear attack.

Measurement and DSP

Frequency response: How evenly a system reproduces frequencies across a range, shown as level against frequency.

Directivity: How a speaker's output spreads with angle, which sets the character of room reflections.

Off-axis response: The response measured away from the central axis, heard via room reflections.

DSP: Digital signal processing: using digital filters to adjust a signal, for example to correct a monitor or compensate for the room.

Room correction: Measurement-based digital filtering applied to the monitor signal to compensate for the room's response.

FIR / IIR: The two digital filter families. IIR is efficient and minimum-phase; FIR is always stable and can be linear phase.

LUFS: Loudness Units relative to Full Scale, a perceptual loudness measure used for metering and streaming normalisation.

Equal-loudness contours: Curves showing how the ear's frequency sensitivity changes with level, which is why balance shifts with volume.

Frequently Asked Questions

How should I use this glossary?

As a reference while reading the other guides, or to check the precise meaning of a term. Entries are grouped by topic so related ideas sit together, and many concepts have a full article linked from the relevant guide.

What is the difference between a studio monitor and a speaker?

A studio monitor is a loudspeaker built for accurate, neutral reproduction so you can hear a recording as it is. A general speaker may be voiced to sound pleasing. The accuracy is what makes a monitor suitable for mixing.

What does point source mean here?

A design that radiates the whole frequency range from one point, achieved with a single full-range driver or a coaxial. It gives inherent time alignment and stable imaging. See the dedicated point-source article for detail.

Is group delay the same as latency?

Not quite. Latency is a constant delay through a system. Group delay is the delay at each frequency. Constant group delay is just latency and is benign, while group delay that varies with frequency is phase distortion.

What is the difference between FIR and IIR?

Both are digital filters. IIR is recursive, efficient and low-latency and behaves like an analog filter. FIR is non-recursive, always stable, and can be linear phase, at the cost of latency and possible pre-ringing.

Why are some terms defined more precisely than I have seen elsewhere?

Several terms are used loosely in general discussion. Where that happens, the definition states what the term means in this library, so the guides stay consistent and unambiguous.

Conclusion

Use this glossary as a companion to the rest of the library. The definitions are short and practical, grouped so related terms sit together, and consistent with how each idea is used in the full articles. When a term needs more than a sentence, follow the link to its dedicated guide. Clear, shared definitions make the technical articles easier to read and the underlying concepts easier to connect.