Radio Frequency Interference (RFI):
What is radio frequency interference and how does it affect microphones? Radio frequency interference (RFI) is the electromagnetic interference caused by radio frequencies that affect mics and audio equipment. RFI is typically caused by nearby radio and television stations and shows up in the mic signal as the signal the stations are broadcasting.
What is the RAI microphone pair? The RAI pair is a near-coincident stereo miking technique that specifies a pair of cardioid mics spaced 21 cm apart and angled at 100°. The RAI pair was established by the Radio Audizioni Italiane, Italy’s national public broadcasting company.
Rated Load Impedance:
What is a microphone’s rated load impedance? Rated load impedance is a fairly common microphone specification that refers to the minimum input impedance a mic preamp must have in order for the mic to send its signal properly. The load impedance must be much higher than the mic’s output impedance for optimal voltage (mic signal) transfer.
What does the term “reach” mean in reference to a microphone? A microphone’s reach is a loose term for the distance from which the mic will pick up a clean signal without significant ambient noise. This is, of course, subjective, and it also depends on the ambient environment, the reflections, and the level of the sound source.
What are rear ports in a microphone? Top-address pressure-gradient microphones have rear ports to allow sound pressure to reach the backside of their diaphragms. The rear ports of a mic are the start of the backside Acoustic Labyrinth, which phase shifts sound waves relative to the front side and yield a directional polar pattern.
What is a wireless microphone receiver? A wireless microphone receiver has antennae that receive the transmitted wireless mic signal (radio wave) from the mic’s transmitter. The receiver demodulates the radio frequency and outputs the original audio signal from the microphone. Receivers are essential to wireless mic systems.
What is the Recorderman technique of microphone placement? The Recorderman technique is a 2-cardioid stereo miking technique for drum kits. One mic is placed 32″ above the snare drum and points straight down. The other mic is positioned near the drummer’s right shoulder in a way that makes it equidistant with the first mic to both the snare and kick drums.
What is a reflection in terms of sound and microphones? A reflection is when a sound wave bounces off a surface. Echoes and reverberation are made of reflections and may yield wanted or unwanted effects in a mic signal. Too many reflections and the direct sound is drowned out in a mic signal. Too few reflections and the mic signal may sound overly dry.
Also known as an acoustic shield.
What is a microphone reflection shield? A microphone reflection shield is a sound absorption device that is placed behind and/or around a mic to help prevent reflections from reaching the mic capsule. It also hinders the direct source’s sound waves from reaching the reflective surfaces in the first place (especially with close-miked vocals).
To learn about my recommended reflection shields, check out Best Vocal Microphone Isolation Shields.
What is microphone rejection? Microphone rejection is the relative decrease in sensitivity as a sound source moves off-axis around a directional mic’s pickup pattern. Rejection is greatest at the mic’s null points, which are essential for gain-before-feedback issues when mics and monitors are used together.
What is electrical resistance and why is it important to microphones? Electrical resistance is the measurement (in ohms) of the resistance of electrical flow in a circuit. Resistance applied to AC signal (such as mic signals) is known as impedance. However, resistance still plays a major role in the circuit theory or microphone design.
What is a resistor and what are resistors important to microphones? A resistor is a passive two-terminal electronic component that causes resistance in a circuit. Resistors play crucial roles in microphone design, including the adjustment of signal levels, biasing of active components, signal filtering, and general mic safety.
What is reverberation and how does it affect microphones? Reverberation is the decaying residual sound after an initial sound occurs. It’s created by sounds reflecting off surfaces in an acoustic space. There are three distinct parts of reverberation: initial reflection, early reflections, and late reflections (reverb tail).
RF Condenser Microphone:
Also known as an RF capacitor microphone.
What is an RF condenser microphone? RF condenser mics (RFCs) use a low RF voltage from a low-noise oscillator to polarize their capsules. As capsule capacitance varies, the RF voltage is modulated and a mic signal is created. RFCs have flatter frequency response, lower noise, and are better in weather than FET or tube condensers.
What is a microphone ribbon? A microphone ribbon is a thin ribbon-like diaphragm made of conductive metal (often corrugated aluminum). These “ribbons” acts as the diaphragm in ribbon microphones, creating a mic signal via electromagnetic induction as they vibrate in the ribbon mic’s magnetic field.
What is a ribbon microphone? A ribbon microphone in a type of dynamic mic that utilizes a thin, conductive, corrugated ribbon-like diaphragm to convert sound energy to mic signals via electromagnetic induction. Ribbon mics are typically very accurate, bidirectional, low-output mics with slight high-frequency roll-off.
For more information on dynamic ribbon mics, check out my article Dynamic Ribbon Microphones: The In-Depth Guide.
What is a ribbon motor? A ribbon motor is essentially the equivalent of a capsule in a ribbon microphone. It is the transducer mechanism inside the ribbon mic that converts sound to audio signals. A ribbon motor is made of a conductive ribbon-like material (diaphragm) and a permanent magnet and its pole pieces.
Ringo Starr Drum-Miking Technique:
What is the Ringo Starr drum-miking technique? The Ringo Starr drum-miking technique is a two-microphone mono technique used on many of The Beatles’ recordings. One mic is positioned about 1 ft. in front of the kick drum at the height of the beater. The other mic is positioned over the centre of the kit about 1 ft. above the drummer’s head.
What is a room microphone? A room mic is positioned to capture the full sound of a source along with the sound of the physical space. Room mics are often set up in stereo pairs in order to provide more detail in a stereo mix. Room mic positioning is often in a room’s sweet spot or at the critical distance from a sound source.
To learn about my recommended room microphones, check out my article Best Room Microphones.
What is room tone? Room tone is the recording of the ambient sound of any acoustic space before or after a performance with all microphones in the same position and the preamp gain of those microphones at the same level. Recording room tone helps in post-production editing and noise cancellation.