1.2 Microphones

Microphones are the unsung heroes of TV studio production, capturing every word and sound that brings shows to life. From dynamic workhorses to sensitive condensers, each type has its strengths. Understanding their polar patterns, frequency responses, and placement techniques is key to achieving crystal-clear audio.

Wireless systems offer freedom of movement, while accessories like shock mounts and pop filters refine the sound. Proper care and maintenance ensure these essential tools stay in top shape. Mastering microphone basics empowers producers to create professional-quality audio that enhances any production.

Types of microphones

• Microphones are essential tools in TV studio production used to capture audio from various sources such as vocals, instruments, and ambient sounds
• Different types of microphones have unique characteristics and are suited for specific applications in a studio setting

Dynamic vs condenser

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• Dynamic microphones are rugged, reliable, and handle high sound pressure levels (drums, guitar amps)
  • Utilize a moving coil attached to a diaphragm to convert sound waves into electrical signals
  • Less sensitive to high frequencies and have a lower output level compared to condenser mics
• Condenser microphones are more sensitive, capture detailed high frequencies, and are ideal for vocals and acoustic instruments
  • Require phantom power (48V) to charge the capacitor plates that convert sound waves into electrical signals
  • More fragile and susceptible to moisture and extreme temperatures compared to dynamic mics

Ribbon microphones

• Ribbon microphones use a thin metal ribbon suspended between two magnets to capture sound
• Known for their warm, natural sound and figure-8 polar pattern
• Fragile and sensitive to wind and phantom power, requiring careful handling
• Often used for capturing vintage-sounding vocals, brass instruments, and guitar amps

USB microphones

• USB microphones have built-in preamps and analog-to-digital converters, allowing direct connection to a computer
• Convenient for podcasting, voiceovers, and home studio recording
• Quality varies among models, with some offering comparable performance to traditional XLR microphones
• Limited flexibility in terms of placement and compatibility with professional audio interfaces

Microphone polar patterns

• Polar patterns describe a microphone's sensitivity to sound from different directions
• Understanding polar patterns helps in selecting the right microphone for a given situation and minimizing unwanted noise

Omnidirectional pattern

• Omnidirectional microphones pick up sound equally from all directions (360 degrees)
• Useful for capturing ambient sound, room acoustics, and multiple speakers in a group setting
• Less susceptible to proximity effect (bass boost when close to the sound source)
• Prone to picking up unwanted background noise in untreated environments

Cardioid pattern

• Cardioid microphones are most sensitive to sound directly in front, with reduced sensitivity on the sides and rear
• The most common polar pattern for vocal microphones and instruments in live and studio settings
• Provides good isolation from other sound sources and helps reduce feedback in live situations
• Exhibits proximity effect, which can be used creatively or controlled with microphone technique

Supercardioid and hypercardioid patterns

• Supercardioid and hypercardioid microphones have a narrower front pickup angle and greater rejection of side and rear sounds compared to cardioid
• Provide excellent isolation and feedback resistance in live sound reinforcement
• Have a small rear lobe of sensitivity, which can pick up unwanted sounds if not positioned carefully
• Require more precise aiming towards the sound source to achieve consistent results

Bidirectional (figure-8) pattern

• Bidirectional microphones are equally sensitive to sounds from the front and rear, with minimal pickup on the sides
• Useful for recording two speakers facing each other or capturing room ambience
• Can be used in conjunction with other microphones to create stereo recording techniques (Mid-Side, Blumlein)
• Prone to picking up sounds from the rear, which may require careful positioning and acoustic treatment

Microphone frequency response

• Frequency response describes a microphone's sensitivity to different frequencies in the audible spectrum (20 Hz to 20 kHz)
• Microphone choice based on frequency response characteristics can greatly impact the overall sound quality in a TV studio production

Flat response

• A flat frequency response microphone aims to capture sound accurately without emphasizing or attenuating any particular frequencies
• Ideal for applications that require a neutral, uncolored sound (measurement microphones, classical music recording)
• In practice, most microphones have some variations in their frequency response due to design limitations and intended applications
• Flat response microphones are often used as a reference point for comparing other microphones or as a starting point for post-production EQ

Tailored response for vocals

• Many vocal microphones have a tailored frequency response that emphasizes certain frequencies to enhance clarity, presence, and intelligibility
• Common boosts in the 2-5 kHz range to add clarity and help vocals cut through a mix
• Gentle roll-off in the lower frequencies to reduce proximity effect and minimize handling noise
• Some microphones have a high-frequency boost (air boost) around 10-15 kHz to add brightness and sheen to vocals

Low-frequency roll-off

• Low-frequency roll-off (high-pass filter) reduces the microphone's sensitivity to low frequencies, typically below 80-100 Hz
• Helps to minimize the pickup of unwanted low-frequency sounds (rumble, wind noise, footsteps)
• Can be implemented electronically within the microphone or as an external filter in the preamp or mixer
• Useful for reducing proximity effect and cleaning up the low-end in a mix, especially when using multiple microphones

Microphone sensitivity and noise

• Microphone sensitivity and noise characteristics play a crucial role in determining the overall signal quality and usability in various recording situations

Sensitivity ratings

• Microphone sensitivity refers to the microphone's output level for a given sound pressure level (SPL) input
• Typically expressed in millivolts per pascal (mV/Pa) or decibels relative to 1 volt per pascal (dBV/Pa)
• Higher sensitivity microphones produce a stronger output signal, requiring less preamp gain and potentially offering a better signal-to-noise ratio
• Lower sensitivity microphones may be preferred in high SPL environments (drum kits, guitar amps) to avoid overloading the preamp

Self-noise and signal-to-noise ratio

• Self-noise refers to the inherent electrical noise generated by the microphone's electronics, measured in equivalent noise level (EIN) or A-weighted decibels (dBA)
• Signal-to-noise ratio (SNR) compares the microphone's output level to its self-noise level, expressed in decibels (dB)
• Higher SNR values indicate a cleaner, quieter microphone with a better ability to capture low-level sounds without noise interference
• Condenser microphones generally have lower self-noise and higher SNR compared to dynamic microphones

Techniques for reducing noise

• Choose microphones with low self-noise and high signal-to-noise ratio for critical recording applications
• Use balanced XLR connections to minimize electromagnetic interference and noise pickup over long cable runs
• Employ proper shielding and grounding techniques in the recording environment to reduce electrical noise
• Utilize noise reduction software or plugins in post-production to further clean up the audio signal
• Implement acoustic treatment in the recording space to minimize room reflections and ambient noise

Microphone placement techniques

• Proper microphone placement is essential for achieving the desired sound quality, isolation, and stereo imaging in TV studio production

Close miking vs distant miking

• Close miking involves placing the microphone within a few inches of the sound source (vocals, instruments)
  • Provides better isolation from other sounds and higher signal-to-noise ratio
  • Captures more direct sound and less room ambience, resulting in a tighter, more focused sound
  • Prone to proximity effect, which can be used creatively or controlled with microphone technique and EQ
• Distant miking involves placing the microphone further away from the sound source (several feet or more)
  • Captures more room ambience and natural reverb, creating a more spacious and open sound
  • Useful for capturing the overall sound of an ensemble or the acoustics of a room
  • Requires a quieter recording environment and may be more susceptible to noise and leakage from other sources

Miking for different instruments

• Vocals: Close-miked with a cardioid condenser or dynamic microphone, aimed towards the mouth and slightly off-axis to minimize plosives
• Acoustic guitar: Combination of close-miking (near the 12th fret or sound hole) and distant-miking for a balanced sound
• Electric guitar amp: Close-miked with a dynamic microphone (SM57) on the speaker cone, off-axis to capture the desired tone
• Drums: Multiple microphones for each drum (snare, toms, kick) and overheads to capture the cymbals and overall kit sound
• Piano: Pair of condenser microphones placed inside the piano, near the hammers for a bright sound or closer to the strings for a warmer tone

Stereo miking techniques

• XY technique: Two cardioid microphones with their capsules placed close together at a 90-degree angle, providing a wide stereo image with good mono compatibility
• ORTF technique: Two cardioid microphones spaced 17cm apart with a 110-degree angle between them, mimicking the position of human ears for a natural stereo perspective
• Spaced pair: Two identical microphones (often omnidirectional) placed several feet apart, capturing a wider stereo image with more room ambience
• Mid-Side (MS): A cardioid microphone (Mid) facing the sound source and a bidirectional microphone (Side) positioned perpendicular, allowing for adjustable stereo width in post-production

Avoiding plosives and sibilance

• Plosives are strong bursts of air caused by consonants (P, B, T, D) that can result in low-frequency thumps or distortion
• Sibilance refers to the harsh, high-frequency sounds created by consonants (S, F, SH)
• Position the microphone slightly off-axis (to the side) of the mouth to minimize direct air blasts
• Use a pop filter or windscreen to diffuse the air and reduce the impact of plosives
• Employ a de-esser plugin in post-production to attenuate excessive sibilance without affecting the overall sound

Wireless microphone systems

• Wireless microphone systems provide freedom of movement for performers and reduce the clutter of cables in a TV studio production

VHF vs UHF frequencies

• VHF (Very High Frequency) wireless systems operate between 30 MHz and 300 MHz
  • More susceptible to interference from TV broadcasts, radio stations, and other electronic devices
  • Longer wavelengths allow for better signal penetration through obstacles but require larger antennas
• UHF (Ultra High Frequency) wireless systems operate between 300 MHz and 3 GHz
  • Less prone to interference and offer more available frequencies for simultaneous use
  • Shorter wavelengths provide better signal rejection of reflections but may be more susceptible to absorption by obstacles

Analog vs digital wireless

• Analog wireless systems transmit audio as a continuous waveform, modulating the signal onto a carrier frequency
  • Prone to noise, hiss, and interference, especially at longer distances or in crowded RF environments
  • Require companding (compression-expansion) to improve the signal-to-noise ratio, which can introduce artifacts
• Digital wireless systems convert audio into a digital bitstream before transmission, offering improved sound quality and resistance to interference
  • Provide a cleaner, more transparent sound with extended dynamic range and frequency response
  • Enable secure transmission with encryption to prevent unauthorized access
  • May introduce a slight latency (delay) due to the analog-to-digital and digital-to-analog conversion process

Transmitters and receivers

• Transmitters convert the audio signal from the microphone into a radio signal and broadcast it to the receiver
  • Body-pack transmitters are small, portable units that can be clipped to clothing or worn on a belt
  • Handheld transmitters integrate the microphone capsule and transmitter into a single unit, resembling a traditional wired microphone
• Receivers pick up the radio signal from the transmitter and convert it back into an audio signal
  • Single-channel receivers are designed to work with one transmitter at a time
  • Multi-channel receivers can simultaneously receive signals from multiple transmitters, allowing for the use of multiple wireless microphones

Antenna placement and diversity

• Proper antenna placement is crucial for ensuring reliable reception and minimizing dropouts or signal loss
  • Place antennas high and away from metal objects, walls, and other potential sources of interference
  • Use remote antennas connected via low-loss coaxial cables for better reception in larger or complex environments
• Diversity reception involves using two or more antennas to receive the signal and automatically switch to the strongest signal
  • Spatial diversity uses two antennas spaced apart to minimize signal dropouts caused by multipath interference
  • Frequency diversity uses two antennas tuned to slightly different frequencies to avoid interference on a single frequency
  • Polarization diversity uses two antennas with different polarizations (vertical and horizontal) to reduce signal fading

Microphone accessories

• Various microphone accessories are used to improve the functionality, versatility, and sound quality of microphones in a TV studio production

Microphone stands and booms

• Microphone stands provide stable support for microphones, allowing for precise positioning and hands-free operation
  • Straight stands are simple, vertical stands suitable for most general-purpose applications
  • Boom stands have an adjustable arm that allows for positioning the microphone closer to the sound source or in hard-to-reach places
• Booms are long, adjustable arms that can be attached to stands or mounted on walls or ceilings for suspending microphones overhead
  • Useful for miking drums, choirs, or capturing room ambience without visible stands in the shot
  • Can be equipped with counterweights to balance heavier microphones and prevent tipping

Shock mounts and isolation

• Shock mounts are designed to isolate the microphone from mechanical vibrations and handling noise transmitted through the stand or boom
  • Consist of an elastic suspension system (rubber bands, springs) that decouples the microphone from the mount
  • Particularly useful for sensitive condenser microphones in a studio setting
• Isolation pads or decouplers can be placed under microphone stands to reduce the transfer of floor vibrations
  • Made of dense, shock-absorbing materials (foam, rubber) that effectively dampen low-frequency vibrations
  • Ideal for use on hollow stages, sprung floors, or in areas with heavy foot traffic

Pop filters and windscreens

• Pop filters are designed to reduce plosives (strong bursts of air) caused by certain consonants (P, B, T, D) in vocal recordings
  • Consist of a fine mesh or metal screen mounted a few inches in front of the microphone capsule
  • Diffuse the air blasts without significantly affecting the overall sound quality
• Windscreens are used to minimize wind noise and breath sounds when recording in outdoor or windy environments
  • Made of foam, fur, or other wind-resistant materials that cover the microphone capsule
  • Reduce the impact of wind gusts and air movement on the microphone diaphragm
  • Some windscreens also provide a degree of moisture resistance for use in humid or damp conditions

Cables and connectors

• Microphone cables are used to transmit the audio signal from the microphone to the preamp, mixer, or recording device
  • Balanced XLR cables are the most common, offering noise rejection and long cable runs without signal degradation
  • Unbalanced cables (TS or TRS) are less expensive but more susceptible to noise and interference, suitable for shorter cable runs
• Connectors are the plugs and jacks that allow microphones to interface with other audio equipment
  • XLR connectors are the standard for professional microphones, providing a secure, locking connection and balanced signal transfer
  • TRS (Tip-Ring-Sleeve) and TS (Tip-Sleeve) connectors are used for unbalanced connections, often found on consumer-grade microphones and audio devices
  • USB and other digital connectors are used for microphones with built-in preamps and analog-to-digital converters, allowing direct connection to computers or digital recording devices

Microphone maintenance and care

• Proper maintenance and care are essential for ensuring the longevity, reliability, and optimal performance of microphones in a TV studio production

Proper handling and storage

• Always handle microphones with clean, dry hands to avoid transferring oils, sweat, or dirt to the microphone body and grille
• Use a microphone clip or stand to securely hold the microphone, avoiding direct contact with the capsule or grille
• Store microphones in a cool, dry place away from direct sunlight, heat, and humidity
  • Keep microphones in their original cases or pouches when not in use to protect them from dust, impact, and environmental factors
  • Avoid storing microphones in areas with strong electromagnetic fields (near monitors, power amplifiers) to prevent interference and damage

Cleaning and disinfecting

• Regularly clean microphone bodies and grilles to remove dust, dirt, and debris that can accumulate over time
  • Use a soft, dry cloth or brush to gently wipe down the microphone surface, taking care not to damage the capsule or grille
  • For more stubborn dirt or stains, use a slightly damp cloth with mild soap and water, then dry the microphone thoroughly
• Disinfect microphones that are shared among multiple users to prevent the spread of germs and illness
  • Use alcohol-based wipes or sprays designed for use on electronic equipment, avoiding excess moisture that can damage the microphone
  • Allow the microphone to dry completely before storing or using it again

Troubleshooting common issues

• No sound or low output:
  • Check that the microphone is properly connected to the preamp, mixer, or recording device
  • Verify that the microphone is powered on (if applicable) and that the cables are securely plugged in
  • Ensure that the preamp or mixer gain is set appropriately and not muted
• Distorted or clipping soun