Hi-Fi Audio Glossary — AudioChainHiFi.com

C

Cantilever: The slender rod that extends from a phono cartridge body and holds the stylus at its tip. As the stylus tracks a record groove, vibrations travel up the cantilever and into the generator (magnet or coil assembly). Cantilever material — aluminum, boron, sapphire, ruby — significantly affects the transient response and high-frequency resolution of the cartridge. Stiffer, lighter materials like boron allow faster response but are more expensive to manufacture.
Compliance (Static & Dynamic): A measure of how freely a phono cartridge's cantilever moves in response to lateral force. Expressed in units of 10⊃;−⁶ cm/dyne (or equivalently µm/mN). Higher compliance means a more freely moving stylus — ideal for low-mass tonearms. Dynamic compliance (measured at 100 Hz) is the figure most relevant to calculating tonearm resonance frequency. The resonance of a cartridge-tonearm system should ideally fall between 8 Hz and 12 Hz for stable, low-distortion playback.
Crosstalk: The amount of signal from one audio channel that bleeds into the other channel. Measured in decibels (dB), with higher values indicating better channel separation. A cartridge with 25 dB of channel separation and a preamp with 80 dB of crosstalk rejection will have the cartridge as the limiting factor — the overall stereo separation of the system is determined by the weakest link in the chain.

D

Damping Factor: The ratio of the speaker's nominal impedance to the amplifier's output impedance. A damping factor of 200 means the amplifier's output impedance is 1/200th of the speaker's impedance. Higher damping factors give the amplifier tighter electrical control over the speaker's cone, reducing overhang and improving bass definition. Damping factor is frequency-dependent — specifications are typically measured at 20 Hz or 1 kHz — and real-world values are affected by speaker cable resistance.
DAC (Digital-to-Analog Converter): A component that converts digital audio data (PCM or DSD streams) into an analog voltage signal that can be amplified and reproduced through speakers. Key DAC specifications include output voltage (typically 2–4 Vrms), output impedance (ideally below 200 Ω), supported sample rates (44.1 kHz to 768 kHz), supported bit depths (16 to 32 bit), and supported formats (PCM, DSD64, DSD128, DSD256). The output impedance of the DAC must be significantly lower than the input impedance of the preamplifier or integrated amplifier it feeds.
Dynamic Headroom: The difference in decibels between an amplifier's continuous RMS power output and its peak burst power output. Expressed in dB, a headroom figure of 1.5 dB means the amplifier can deliver short-duration peaks roughly 40% above its rated continuous power. Dynamic headroom is important for reproducing musical transients — the brief loud peaks in orchestral music or drum hits — without clipping, even when average listening levels are moderate.

E

Effective Mass (Tonearm): The mass that the phono cartridge "feels" it is moving against, as measured at the stylus tip. It includes the physical mass of the tonearm tube, headshell, cartridge body, and mounting hardware, reduced by the mechanical advantage of the pivot. Effective mass is critical for calculating tonearm-cartridge resonance frequency. Low-compliance cartridges (MC types) pair best with high-mass tonearms; high-compliance cartridges (many MM types) require low-mass arms.

F

Frequency Response: The range of frequencies a component can reproduce within a specified amplitude variation, typically expressed as "20 Hz–20 kHz, ±0.5 dB" or "20 Hz–50 kHz, +0/–3 dB." A flat frequency response across the audible band (20 Hz to 20 kHz) is the baseline standard for high-fidelity reproduction. Extended frequency response beyond 20 kHz can indicate a lower-distortion design even if the additional content is inaudible. The ±dB tolerance is as important as the stated frequency range.

G

Gain: The amplification factor applied to a signal by a component, expressed in decibels (dB). A gain of 6 dB doubles the signal voltage; 20 dB increases it tenfold. Each stage in a signal chain adds gain, and the total system gain must be appropriate for the source signal level to reach the power amplifier's rated output without clipping or introducing excessive noise. Phono preamps typically add 40–65 dB of gain; line preamps add 6–20 dB; power amplifiers add 20–32 dB.
Gain Staging: The practice of setting and matching the gain levels at each stage of a signal chain to minimize noise, avoid clipping, and keep the volume control in a musically useful operating range. Proper gain staging means the signal is strong enough at each point to ride well above the noise floor, but not so strong that it clips the input of the next stage. Poor gain staging is one of the most common causes of system noise and distortion in home audio.

H

HOMC (High-Output Moving Coil): A moving-coil cartridge designed to produce an output voltage high enough (typically 1.5–2.5 mV) to be used directly with a standard MM phono input, without requiring the higher gain and lower input impedance of a true MC phono stage. HOMC cartridges sacrifice some of the resolution and delicacy associated with low-output MC designs, but offer the convenience of MM compatibility while retaining the MC's generator architecture and typically superior channel separation.

I

Impedance: The total opposition to AC current flow in a circuit, combining resistance, capacitance, and inductance. Measured in ohms (Ω). In audio, impedance has two critical roles: the output impedance of one component must be much lower than the input impedance of the component it feeds (the 10:1 rule), and speakers present a complex, frequency-varying impedance load that amplifiers must drive stably. Impedance is not constant across frequency — a speaker rated at 4 Ω may dip to 2.5 Ω at certain frequencies, stressing an amplifier that cannot handle it.
Input Sensitivity: The minimum input signal level (voltage) required for a component to produce its full rated output. A power amplifier with an input sensitivity of 1 V will reach its rated power output when driven by a 1 V RMS signal. If the preamplifier's output voltage significantly exceeds the amplifier's input sensitivity, the volume control will be useful only at very low settings, making precise level control difficult and potentially increasing noise. Input sensitivity directly determines whether a preamp-amplifier pairing will be practical.
IM Distortion (Intermodulation Distortion): Distortion products created when two or more frequencies pass through a non-linear component and combine to create sum and difference frequencies that were not present in the original signal. Unlike harmonic distortion (which produces musically related overtones), IM distortion creates dissonant, non-harmonic frequencies that are particularly audible and unpleasant. A component with excellent THD figures but poor IM distortion specs may still sound harsh or fatiguing on complex musical program material.

L

Load Impedance (Cartridge): The input impedance of the phono preamp as seen by the cartridge. For MM cartridges, the standard load is 47 kΩ. The load interacts with the cartridge's inductance to form a resonant circuit that affects frequency response — incorrect loading causes MM cartridges to exhibit a rising high-frequency peak. For MC cartridges, loading is more critical and typically ranges from 50 Ω to 1000 Ω; too low a load damps the cartridge and rolls off treble, while too high allows excessive resonance and brightness.
LOMC (Low-Output Moving Coil): A moving-coil phono cartridge producing a very low output voltage, typically 0.2–0.6 mV. LOMC cartridges require a phono preamp with dedicated MC gain (typically 60–70 dB) and a low input impedance (typically 50–500 Ω). The low-output design allows for a very small, lightweight coil assembly mounted to the cantilever, which results in excellent transient response and channel separation. Most reference-grade phono cartridges are LOMC designs.

M

MC (Moving Coil) Cartridge: A phono cartridge in which the coils are attached to the cantilever and move within a fixed magnetic field, generating an electrical signal. MC cartridges typically have very low output voltage (0.2–2.5 mV), very low internal impedance (3–200 Ω), and excellent channel separation due to the tight coil geometry. They require more gain and lower-impedance phono stages than MM designs. The cantilever-mounted coils allow a lighter-weight generating assembly, which contributes to superior transient response.
MM (Moving Magnet) Cartridge: A phono cartridge in which a small magnet is mounted to the cantilever tip and moves between fixed coils, generating an electrical signal. MM cartridges produce higher output voltages (3–6 mV) and present higher impedance to the phono stage (1–2 kΩ internally, loaded at 47 kΩ). They are compatible with the standard phono input found on virtually all integrated amplifiers and receivers. MM cartridges typically have replaceable styli, making them more economical to maintain.

N

Noise Floor: The level of background electrical noise present in a system when no audio signal is present, typically expressed as a voltage level or as the Signal-to-Noise Ratio. A lower noise floor means the system is quieter. The noise floor of a complete system is determined by its noisiest component — often the phono preamplifier for analog sources, or the DAC for digital sources. Excessive system gain, impedance mismatches, and poor shielding all raise the effective noise floor.

O

Output Impedance: The source impedance presented by a component's output stage to the component it drives. For proper signal transfer, output impedance should be at least 10 times lower than the input impedance of the following component (the 10:1 rule). A preamplifier with a 1,000 Ω output impedance driving an amplifier with a 5,000 Ω input impedance violates this guideline and will result in a measurable and often audible high-frequency rolloff and dynamic compression.

P

Peak Current Delivery: The maximum instantaneous current (in amperes) an amplifier can deliver to a speaker load. Measured in amps peak per channel. High peak current capability allows an amplifier to maintain control over difficult, low-impedance speaker loads and reproduce transient peaks without voltage sag or clipping. An amplifier may be rated for modest continuous power into 8 Ω while still having excellent peak current delivery that makes it suitable for demanding 4 Ω or lower loads.
Phono Stage / Phono Preamp: A preamplifier specifically designed for phono cartridge signals, performing two essential functions: amplifying the very low cartridge output voltage to line level, and applying the RIAA equalization curve to correct for the frequency pre-emphasis applied during record cutting. MM phono stages provide 35–45 dB of gain with 47 kΩ input impedance. MC stages provide 55–70 dB of gain with adjustable input impedances from 50–1000 Ω.
Power Output (RMS): The continuous power an amplifier can deliver into a specified load impedance, measured in watts RMS. RMS (Root Mean Square) power represents the continuous power equivalent of a sine wave signal, making it a meaningful measure of sustained loudness capability. Power output is always specified with a load impedance (8 Ω, 4 Ω, 2 Ω) and should be measured with both channels driven simultaneously for a realistic stereo specification. Many amplifiers deliver significantly more power into 4 Ω than 8 Ω loads.

R

RIAA Equalization: A standardized frequency-response curve applied during vinyl record cutting and playback. During cutting, bass frequencies below 1 kHz are reduced in level and treble frequencies above 1 kHz are boosted, allowing more music to fit on a record side while controlling groove width. A phono preamp applies the inverse curve during playback — boosting bass and cutting treble — to restore flat frequency response. Inaccurate RIAA correction in a phono preamp results in a characteristic tonal coloration across the entire audible range.
Resonance Frequency (Tonearm-Cartridge): The frequency at which the combined mechanical system of the phono cartridge and tonearm oscillates when excited. Determined by the tonearm's effective mass and the cartridge's dynamic compliance, calculated as: F = 1000 / (2π × √(M × C)), where M is effective mass in grams and C is compliance in 10−⁶ cm/dyne. The ideal resonance frequency is 8–12 Hz — low enough to be below the audible range, high enough to avoid susceptibility to record warps (which produce energy at 0.5–3 Hz).

S

Sensitivity (Speaker): The sound pressure level (SPL) a speaker produces at 1 meter distance when driven with 1 watt of pink noise (or equivalently 2.83 V RMS into 8 Ω). Expressed in dB/W/m or dB/2.83V/1m. A speaker with 90 dB sensitivity produces twice the loudness of an 87 dB speaker with the same amplifier — a 3 dB increase in SPL requires doubling power. High-sensitivity speakers (92 dB+) pair well with low-power amplifiers; low-sensitivity speakers (84 dB and below) benefit from more powerful amplification.
SNR (Signal-to-Noise Ratio): The ratio between the level of a desired audio signal and the level of background noise, expressed in decibels. A higher SNR indicates a quieter component. SNR is typically specified at rated output power and measured A-weighted (reflecting the frequency sensitivity of human hearing) or unweighted. A phono preamp SNR of 80 dB (A-weighted, MM) is adequate; 85 dB+ is good; 90 dB+ is excellent. For MC stages, 70 dB is adequate due to the greater gain required.
Stylus Shape: The geometry of the diamond tip that contacts the record groove. Common shapes include: Spherical/Conical — simplest, most forgiving of alignment, lowest resolution; Elliptical — contacts more groove wall, better high-frequency tracing and lower distortion; Line-Contact / MicroLine — thin profile traces the original cutting stylus path more closely, excellent HF detail and lower groove wear; Shibata / Gyger — ultra-thin contact patch, exceptional resolution but highly sensitive to alignment accuracy.

T

THD (Total Harmonic Distortion): The ratio of the sum of all harmonic overtones generated by a component (at frequencies not present in the original signal) to the level of the original signal itself, expressed as a percentage. A THD of 0.1% means harmonic distortion products total 0.1% of the signal level. THD should always be specified at a given output level — "0.01% THD at 1 watt" and "1% THD at full output" can both be true of the same amplifier. Low THD at full rated output is more meaningful than low THD at minimal power.
Tracking Force (VTF): The downward force applied by the tonearm to press the stylus into the record groove, measured in grams. Also called Vertical Tracking Force (VTF). The tracking force must be set within the cartridge manufacturer's specified range — too light and the stylus skips out of groove modulations, causing distortion and potential groove damage; too heavy increases stylus and groove wear. Most modern cartridges track between 1.5 and 2.5 grams. The recommended tracking force (usually the middle of the range) typically gives the best combination of distortion, compliance, and record preservation.

V

VTA (Vertical Tracking Angle): The angle at which the stylus contacts the record groove relative to the record surface, ideally matching the angle used by the cutting stylus (typically 20°). If the tonearm is not level or the cartridge is not mounted at the correct height, the effective VTA is incorrect and the stylus traces the groove at the wrong angle, introducing a form of distortion called Vertical Tracking Error. VTA/SRA (Stylus Rake Angle) adjustment is a fine-tuning procedure most relevant for line-contact and Shibata-type stylus profiles.

W

Watt (W) / Power Handling: The unit of electrical power. Speaker power handling specs indicate the maximum continuous power the speaker's voice coil can dissipate without damage. Power handling does not directly indicate how loud or dynamic a speaker is — that is determined by sensitivity. A 100W power handling rating with 86 dB sensitivity will be quieter than a 50W rated speaker with 94 dB sensitivity when driven by the same amplifier. Amplifier clipping — not excess power — is the primary cause of tweeter damage in real-world use.