Recording situations

Field recording

Field recording captures sound outside a controlled studio.

• listen to the environment before choosing microphone, position, and perspective
• capture both ambience and focused sound events
• document location, conditions, equipment, and recording settings

Film production sound

Production sound captures usable synchronized dialogue and actions on every filmed take.

• a boom microphone is often the primary dialogue source
• microphone placement follows framing, movement, and the intended acoustic perspective
• monitor every take and report noise, interference, distortion, or obscured dialogue
• record room tone, ambience/atmos, and wild dialogue or effects as supplementary material

Studio recording

A studio or recording booth provides controlled acoustics for voices, instruments, and sound objects.

• select the microphone according to the source and desired character
• use a shock mount and pop filter when appropriate
• adjust microphone distance and position with the voice talent
• conduct a sound check to set gain, verify headphone monitoring, and listen back before recording complete takes

Audio transducers

A transducer converts energy from one form into another, such as sound pressure into an electrical signal or vice versa.

Dynamic microphones

Moving-coil microphones are robust, tolerate high sound pressure levels, and normally require no external power.

Cardioid and supercardioid patterns are common for handheld speech, live performance, and loud sources.

Example: Shure SM58
Cardioid moving-coil microphone

Condenser microphones

Condenser microphones typically have higher sensitivity and output level than moving-coil microphones.

They are available with fixed or switchable polar patterns for studio, boom, stereo, and quiet-source recording.

Example: Neumann U 87
Condenser microphone with three selectable polar patterns

Other microphone types

• ribbon microphone: velocity-sensitive microphone, often used in studios
• contact / piezo transducer: captures vibration through a solid object
• hydrophone: records pressure changes underwater
• electromagnetic pickup: converts electromagnetic fields into audio signals
• parabolic system: concentrates sound from a distant source onto a microphone

Shotgun microphones

Shotgun microphones use an interference tube to increase directionality. They are common in film, broadcast, interviews, and wildlife recording when the microphone must remain outside the frame or at some distance from the source.

They reduce off-axis sound but do not remove room reflections.

Microphone specifications

• frequency response: variation in output level with frequency
• directivity / polar pattern: variation in sensitivity with direction
• sensitivity: output voltage for a specified sound pressure
• maximum SPL: highest sound pressure level before excessive distortion
• self-noise: noise generated by the microphone electronics

Microphone frequency response

The frequency response of a microphone describes how its sensitivity varies with frequency, usually shown as relative output level across the audible range from approximately 20 Hz to 20 kHz.

Polar patterns

Sensitivity to sound from different directions:

• omnidirectional: responds from all directions; no proximity effect
• cardioid: broad frontal pickup; reduced sensitivity at the sides; greatest rejection at the rear
• supercardioid / hypercardioid: narrower frontal response with some rear pickup
• figure-8: responds to the front and rear while rejecting the sides

The pattern affects source isolation, room sound, placement, and stereo technique.

Proximity effect

Directional microphones increase their low-frequency response at close distances.

• with speech and vocals, the effect is often noticeable within 10–15 cm and pronounced at only a few centimetres
• its strength varies with the microphone and polar pattern
• it can make voices sound warmer or excessively boomy

Phantom power

Phantom power supplies DC voltage through the same balanced connection that carries the microphone signal.

• equal voltage is applied to both signal conductors relative to ground
• P48 is most common (P12 and P24 are also specified)
• many condenser microphones and some active microphones, DI boxes, and inline devices require it

Phantom power circuit

Using phantom power

Use phantom power only when required. With some equipment or wiring, it may introduce noise; some passive (vintage) ribbon microphones require caution.

Recommended procedure

• check the device documentation and required voltage
• connect with phantom power off and monitoring muted
• switch it off before disconnecting equipment

Balanced microphone connections

A balanced connection uses two signal conductors plus a shield, helping preserve signal quality over long cable runs.

• symmetrical: equal signals with opposite polarity
• impedance-balanced: signal on one conductor; matching impedance on the other

→ A differential input rejects interference shared by both conductors.

Balanced and unbalanced signal transmission

Common-mode interference rejection

A differential input subtracts the two conductor voltages:

For audio signal and common interference :

• opposite-polarity drive:
• impedance-balanced drive:

→ The common interference cancels in both cases.

The connector does not define signal type (balanced/unbalanced, mono/stereo)

Microphone selection and perspective

Choose microphone type and distance for the source, environment, and intended perspective.

Distance: closer placement emphasizes direct sound and isolation; greater distance includes more room, ambience, and ensemble balance.

Critical distance and microphone placement

Close-miking a voice

Use one cardioid microphone on a stand as a simple starting point.

• place the capsule approximately 10–20 cm from the mouth
• use a pop filter to reduce plosives
• keep the distance consistent during the performance
• monitor proximity effect, room sound, movement or rustling, and clipping

Boom microphone technique

A microphone on a boom pole follows a voice or action while the operator remains outside the image.

• position it above or below, as close as framing allows
• aim toward the upper chest and maintain a consistent distance
• use a shock mount and suitable wind protection
• listen for handling noise and changes in level or tone and check the frame for the boom and its shadow

Controlling unwanted sound

• match wind protection to the conditions: foam for light air, blimp and fur for stronger wind
• use a shock mount to reduce vibration and handling noise
• move closer and aim the microphone to favor the wanted sound
• for studio or booth voice recording, use a pop filter to reduce plosives

Stereo recording

Stereo microphone techniques capture a spatial image through differences between two channels:

• time-of-arrival differences (spaced microphones)
• level differences (coincident microphones)
• combined time and level differences (near-coincident microphones)

Stereo microphone techniques

• A/B: spaced microphones, usually omnidirectional; stereo image mainly from interchannel time differences
• X/Y: coincident directional microphones, commonly cardioid; stereo image from level differences
• M/S: coincident mid microphone and figure-eight side microphone; decoded to left and right, with adjustable width
• ORTF: cardioids spaced 17 cm and angled 110°; combines time and level differences

Other stereo and spatial recording systems include NOS, the Jecklin disk, dummy-head binaural recording, and Ambisonics.

A–B

X-Y

M/S (mid-side)

ORTF

Portable audio recorders

• built-in microphones for quick recording
• microphone inputs with preamps, phantom power, and gain control
• multitrack models for recording several microphones
• optional timecode for synchronized media production

Recording format, gain, and headroom

dBFS expresses level relative to digital full scale. 0 dBFS is the maximum recording level.

• record uncompressed 48 kHz / 24-bit PCM WAV for a general workflow
• set gain at the recorder or interface preamp
• leave greater headroom for unpredictable or highly dynamic sources
• monitor the meter and listen with headphones

Critical listening with headphones

• Closed-back headphones: isolate from ambient noise
• Flat frequency response: accurate monitoring

Listen for: clipping, distortion, wind, clothing rustle, interference, unwanted sources, and handling noise.

Gain staging: recording and monitoring

Set input gain at the microphone preamp, keep the DAW faders at unity, and control the monitoring level separately.

Recording logs and metadata

A recording log preserves the context needed for editing, reuse, and attribution.

• filename and take number
• date, time, and location
• recorder, interface, preamp, microphone, sample rate, and bit depth
• microphone position and recording conditions
• description, participants, and rights information

Rights and licensing of source material

Before using material:

• identify the creator, performers, source, and rights holder
• establish the basis for use: licence, permission, public domain, or legal exception
• confirm whether editing, synchronization, publication, and redistribution are permitted
• retain the licence, attribution, and consent records where relevant

Clearing sound and music

Generated audio as source material

Text-to-audio and audio-to-audio systems can generate music, ambience, and sound effects.

• generated material can enter the same editing chain as a recording
• prompts and source files become part of the production record
• training data, licensing, consent, and disclosure require attention

Example: Stable Audio generates and edits sound from text or audio input.

Stable Audio

Recording

Choose an environment that could provide material for a montage or installation. Spend time listening, then make a short collection that captures both its continuing ambience and several distinct events. Import and label the material in REAPER.

If recording is not possible, use clearly licensed material from Freesound or create material with a generative-audio service. Document the creator or service, source, licence or terms of use, and—for generated audio—the prompt.

Recording perspective

Seminar exercise with shared recording equipment.

Explore how microphone placement changes the perspective of a short performance. Make and compare several recordings, then select the version that most clearly supports an intended spatial character.

Be prepared to explain the decisions that produced it.

Selected references

• Görne, Thomas. Mikrofone in Theorie und Praxis. 8., neue, überarbeitete und erweiterte Auflage. Elektor, 2007.
• Wuttke, Jörg. Mikrofonaufsätze. Schalltechnik Dr.-Ing. Schoeps, 2000.
• Viers, Ric. The Location Sound Bible. Michael Wiese Productions, 2012.

Related: Fundamentals of Sound · Vibration and Sound · Wave Properties · Room Acoustics · Digital Audio