Professional Microphone Terminology Explained
Figure-8 microphones capture sound equally from front and rear, rejecting side noise (90° off-axis). Typically ribbon or large-diaphragm models.
EQ (Equalizer)
EQ or tone control shapes frequency response. It boosts/cuts energy (amplitude) in specific bands—flattening system response or creatively enhancing instruments.
Listening Recommendations
Use hi-fi speakers, headphones, or headsets to discern subtle differences between mic models. Audio files: Stereo, 192kbps MP3.
Omnidirectional
Omnidirectional mics exhibit equal sensitivity from all angles, ideal for lavalier mics. Disadvantage: Cannot reject unwanted sources (e.g., PA speakers), increasing feedback risk.
Decibel (dB)
dB isn't a unit like feet/pounds—it's a logarithmic ratio comparing values (e.g., voltage): dB = 20 × log(V₁/V₂). Common in electrical/acoustic measurement.
Diversity
Diversity receivers use two antennas for continuous signal reception. If one signal weakens, the other maintains reception, preventing dropouts/noise.
Dynamic Microphone
Robust and economical. Withstands high SPLs and extreme temperatures/humidity. Operation: Diaphragm attaches to voice coil within a magnetic field. Sound vibrates the coil, inducing current.
Dynamic Range
Defined as the difference between max/min SPL a mic can handle. Lower limit depends on equivalent noise level. Unit: dB.
Hemispherical (Half-Cardioid)
Typically boundary mics (e.g., on surfaces) with cardioid-like patterns capturing sound above the surface only.
Compression (Data)
Digital compression formats:
• AAC — Apple
• FLAC — Lossless
• Ogg — Vorbis
• MP3 — Most popular
• WAV — Uncompressed
• WMA — Windows
Compressor (Audio)
Reduces dynamic range. Set threshold; signals exceeding it are attenuated based on ratio (e.g., 2:1 means 2dB input → 1dB output). Attack/release times are critical.
Bidirectional
Synonym for Figure-8. See above.
Feedback
Occurs when PA speakers output sound picked up by mics, re-amplified cyclically. Causes loud "howling."
Large-Diaphragm
Term for condenser mics (diaphragm ≥1"/2.54cm). Adds harmonic richness, smoothing vocals. Small-diaphragm condensers offer flatter response for natural instrument capture.
Wide Cardioid
Captures front/sides with partial rear rejection. Less directional than cardioid; resembles an omni with slight rear attenuation.
Small-Diaphragm
Condenser mics with sub-1" diaphragms. Natural, flat response suits instruments. See "Large-Diaphragm."
Operating Frequency
Specific RF frequency for wireless transmission/reception. Critical: Avoid interference by selecting non-conflicting frequencies per location. Advanced systems offer more channels.
Balanced/Unbalanced Circuits
Unbalanced output: Single conductor (+ shield). Prone to hum/interference.
Balanced output: Two conductors (+ shield) carrying identical signals of opposite polarity. Rejects common-mode noise (hum) via differential amplification.
Phantom Power
Required by all condensers. Typically 48V (sometimes 12V) supplied via mixer. Some use internal batteries for mixer/PC soundcards without phantom power.
Cardioid
Maximum front sensitivity, minimum rear sensitivity. Rejects ambient noise/echoes better than omni—ideal for loud stages.
THD (Total Harmonic Distortion)
Measures distortion generated by devices. Test: Pure sine wave → Device → Distortion analyzer. Residual signal (noise + harmonics) is measured against reference level.
Polar Pattern
Mic's directional sensitivity. Common types: Omnidirectional, Cardioid, Supercardioid.
Transducer
Converts energy forms (e.g., acoustic → electrical). Types: Dynamic, Condenser.
Permanent Bias
Electret condensers use pre-polarized material (electret) on backplate, eliminating external polarization voltage. Still need power (battery/phantom) for preamp.
Sensitivity
Electrical output at given SPL (typically 94dB SPL / 1 Pa). Higher sensitivity = "louder" mic. Units: mV/Pa or dB/Pa.
Condenser/Capacitor Microphone
High sensitivity, natural sound. Requires power. Principle: Charged diaphragm/backplate form capacitor. Sound vibrations alter capacitance, generating signal. Powered via battery/phantom.
Self-Noise
Inherent electronic noise from components/circuits (all electronics > absolute zero generate noise). Combined device/system noise floor defines SNR (signal-to-noise ratio).
Supercardioid
Tighter front pickup than cardioid. Better ambient rejection but retains some rear sensitivity—monitors must be positioned carefully. Optimal for isolating single sources in noise.
Hypercardioid
Even narrower front pickup than supercardioid. Same rear sensitivity considerations. Best for extreme noise isolation.
Proximity Effect
Low-frequency boost when directional mics (cardioid/supercardioid) are placed close to source. Used professionally for vocal fullness. Test by singing progressively closer to mic.
Ribbon/Ribbon Microphone
Thin conductive foil (ribbon) suspended in magnetic field. Sound vibrations induce voltage. Classic figure-8 pattern.
Impedance
Circuit's opposition to AC flow (Ohms). Lower impedance allows more current. Mic output impedance should be << mixer input impedance.
Frequency
Oscillations per second (Hz), determining pitch. In wireless systems: Specific RF frequency for audio transmission. Tx/Rx must match.
Frequency Response
Mic's reproducible frequency range (lowest to highest). Types:
• Flat: Equal sensitivity across audible spectrum (20Hz–20kHz). Ideal for uncolored capture (e.g., recording).
• Tailored: Peaks/dips for specific applications (e.g., 2–8kHz boost for vocal clarity live).
Electret
See "Permanent Bias." Compact, sensitive, natural sound. Requires power.
EQ (Equalizer)
EQ or tone control shapes frequency response. It boosts/cuts energy (amplitude) in specific bands—flattening system response or creatively enhancing instruments.
Listening Recommendations
Use hi-fi speakers, headphones, or headsets to discern subtle differences between mic models. Audio files: Stereo, 192kbps MP3.
Omnidirectional
Omnidirectional mics exhibit equal sensitivity from all angles, ideal for lavalier mics. Disadvantage: Cannot reject unwanted sources (e.g., PA speakers), increasing feedback risk.
Decibel (dB)
dB isn't a unit like feet/pounds—it's a logarithmic ratio comparing values (e.g., voltage): dB = 20 × log(V₁/V₂). Common in electrical/acoustic measurement.
Diversity
Diversity receivers use two antennas for continuous signal reception. If one signal weakens, the other maintains reception, preventing dropouts/noise.
Dynamic Microphone
Robust and economical. Withstands high SPLs and extreme temperatures/humidity. Operation: Diaphragm attaches to voice coil within a magnetic field. Sound vibrates the coil, inducing current.
Dynamic Range
Defined as the difference between max/min SPL a mic can handle. Lower limit depends on equivalent noise level. Unit: dB.
Hemispherical (Half-Cardioid)
Typically boundary mics (e.g., on surfaces) with cardioid-like patterns capturing sound above the surface only.
Compression (Data)
Digital compression formats:
• AAC — Apple
• FLAC — Lossless
• Ogg — Vorbis
• MP3 — Most popular
• WAV — Uncompressed
• WMA — Windows
Compressor (Audio)
Reduces dynamic range. Set threshold; signals exceeding it are attenuated based on ratio (e.g., 2:1 means 2dB input → 1dB output). Attack/release times are critical.
Bidirectional
Synonym for Figure-8. See above.
Feedback
Occurs when PA speakers output sound picked up by mics, re-amplified cyclically. Causes loud "howling."
Large-Diaphragm
Term for condenser mics (diaphragm ≥1"/2.54cm). Adds harmonic richness, smoothing vocals. Small-diaphragm condensers offer flatter response for natural instrument capture.
Wide Cardioid
Captures front/sides with partial rear rejection. Less directional than cardioid; resembles an omni with slight rear attenuation.
Small-Diaphragm
Condenser mics with sub-1" diaphragms. Natural, flat response suits instruments. See "Large-Diaphragm."
Operating Frequency
Specific RF frequency for wireless transmission/reception. Critical: Avoid interference by selecting non-conflicting frequencies per location. Advanced systems offer more channels.
Balanced/Unbalanced Circuits
Unbalanced output: Single conductor (+ shield). Prone to hum/interference.
Balanced output: Two conductors (+ shield) carrying identical signals of opposite polarity. Rejects common-mode noise (hum) via differential amplification.
Phantom Power
Required by all condensers. Typically 48V (sometimes 12V) supplied via mixer. Some use internal batteries for mixer/PC soundcards without phantom power.
Cardioid
Maximum front sensitivity, minimum rear sensitivity. Rejects ambient noise/echoes better than omni—ideal for loud stages.
THD (Total Harmonic Distortion)
Measures distortion generated by devices. Test: Pure sine wave → Device → Distortion analyzer. Residual signal (noise + harmonics) is measured against reference level.
Polar Pattern
Mic's directional sensitivity. Common types: Omnidirectional, Cardioid, Supercardioid.
Transducer
Converts energy forms (e.g., acoustic → electrical). Types: Dynamic, Condenser.
Permanent Bias
Electret condensers use pre-polarized material (electret) on backplate, eliminating external polarization voltage. Still need power (battery/phantom) for preamp.
Sensitivity
Electrical output at given SPL (typically 94dB SPL / 1 Pa). Higher sensitivity = "louder" mic. Units: mV/Pa or dB/Pa.
Condenser/Capacitor Microphone
High sensitivity, natural sound. Requires power. Principle: Charged diaphragm/backplate form capacitor. Sound vibrations alter capacitance, generating signal. Powered via battery/phantom.
Self-Noise
Inherent electronic noise from components/circuits (all electronics > absolute zero generate noise). Combined device/system noise floor defines SNR (signal-to-noise ratio).
Supercardioid
Tighter front pickup than cardioid. Better ambient rejection but retains some rear sensitivity—monitors must be positioned carefully. Optimal for isolating single sources in noise.
Hypercardioid
Even narrower front pickup than supercardioid. Same rear sensitivity considerations. Best for extreme noise isolation.
Proximity Effect
Low-frequency boost when directional mics (cardioid/supercardioid) are placed close to source. Used professionally for vocal fullness. Test by singing progressively closer to mic.
Ribbon/Ribbon Microphone
Thin conductive foil (ribbon) suspended in magnetic field. Sound vibrations induce voltage. Classic figure-8 pattern.
Impedance
Circuit's opposition to AC flow (Ohms). Lower impedance allows more current. Mic output impedance should be << mixer input impedance.
Frequency
Oscillations per second (Hz), determining pitch. In wireless systems: Specific RF frequency for audio transmission. Tx/Rx must match.
Frequency Response
Mic's reproducible frequency range (lowest to highest). Types:
• Flat: Equal sensitivity across audible spectrum (20Hz–20kHz). Ideal for uncolored capture (e.g., recording).
• Tailored: Peaks/dips for specific applications (e.g., 2–8kHz boost for vocal clarity live).
Electret
See "Permanent Bias." Compact, sensitive, natural sound. Requires power.