VID102 DAY 3

Schedule Change Viewing Examples Audio Principles

Class Schedule

Electromagnetic Electrostatic/capacitance Ribbon

Methods of Transduction

Microphone Weaker signal, requires a pre-amp Mic level 2 mV to 1.2V

Professional Line +4dBu 1.23 V

Consumer Line -10dBu .316V

Speaker 4V

Signal Level Types

XLR Balanced 3 conductor

¼ Inch 2 or 3 conductor Balanced or unbalanced

Balanced Minimizes noise and rf interference, uses phase inversion,

helps with longer cable runs Unbalanced

No shielding

Connectors and Cables

The amount of give between your average level and the point of distortion

Clipping is the point at which you exceed your headroom and the limitation of the medium, resulting in distortion

Headroom

You want to have more signal then noise Noise is inherent in the environment and in

the equipment

Signal to Noise Ratio

Way in which a microphone will pick up the sound

This is influenced by the type of transduction Choosing the right polar pattern for the right

situation

Polar Patterns

Omni

Cardioid

Hyper-cardioid

Super-cardioid

Bi-directional

Sound Theory

Types of Transduction (Microphones) Describes the way in which the microphone

converts a sound source into an electrical signal.

Speakers do the reverse, an electrical signal is turned into an acoustic amplified sound Electromagnetic Electrostatic/Capacitance Ribbon

Sound Theory

Types of Transduction (Microphones) Electromagnetic

Dynamic microphone uses electromagnetic induction A small movable induction coil, positioned in the magnetic

field of a permanent magnet, is attached to the diaphragm. When sound enters through the windscreen of the microphone, the sound wave moves the diaphragm. When the diaphragm vibrates, the coil moves in the magnetic field, producing a varying current in the coil through electromagnetic induction.

Commonly used to capture loud percussive sounds with very strong transients.

Does not require an external power source

Sound Theory

Types of Transduction (Microphones) Electrostatic/Capacitance

Require 48v Phantom Power The diaphragm acts as one plate of a capacitor, and the vibrations

produce changes in the distance between the plates.  variety of polar patterns Good at capturing full frequency sounds, captures subtle dynamics of a

performance Frequency Response is better

Ribbon use a thin, usually corrugated metal ribbon suspended in a magnetic

field. The ribbon is electrically connected to the microphone's output, and its vibration within the magnetic field generates the electrical signal. Ribbon microphones are similar to moving coil microphones in the sense that both produce sound by means of magnetic induction.

Microphone Specifications

Usually they are categorized by type of transduction and polar pattern

Polar patterns describe how a microphone will pick up a sound source.

Omni Cardioid Hyper-Cardioid Figure-8 MS

Omnidirectonal

low coloration; they add very little to the original sound. Being pressure-sensitive they can also have a very flat low-frequency response down to 20 Hz or below. Pressure-sensitive microphones also respond much less to wind noise and plosives than directional (velocity sensitive) microphones

Pick up sounds equally from all sides

Cardioid

named because the sensitivity pattern is heart-shaped.

Good rejection 180 degrees off axis (rear)

Pickup equally from the front and the sides

Subject to the proximity effect (closer you are to the source, the lower frequencies will be emphasized)

Fairly directional

Super-Cardioid/Hyper-Cardioid

Good rejection from the sides But some pickup from the rear Fairly directional

Shotgun

Good rejection from the sides

Narrower pickup from the rear

Highly directional Most Boom Microphones

Usually have interference tubing to phase cancel the sides and make more directional

Figure 8

Picks up from the front and rear

Hole in the center Commonly used for M/S

miking technique M/S or Mid Side is a

stereo miking technique which combines a figure 8 with a cardioid microphone, it provides a wide stereo image and when listening on headphones you get a sense of panning better then traditional stereo miking techniques.

Process of recording audio on set Starts in pre-production Specific crew positions Goal is to capture the cleanest possible

recording of set dialogue

Intro to Production Audio

The process of evaluating a location based upon the sound What will prevent you from capturing clean

dialogue What can be done to help you capture clean

dialogue What microphones should you use?

Location Scouting

Analysis of the script with a specific focus on sound Consider possible miking approaches Start thinking about post production Number of actors What equipment will be needed What are possible problems for sound?

Script Break Down

Production Mixer Boom Operator Video Assist Utility

Production Audio Crew

Request Gear Package Goes on the Scouting of locations Is responsible for running the mixer, the

recorder, and taking sound reports

Production Mixer

Is the on set Ninja Places microphones Responsible for positioning them selves

optimally for capturing dialogue without being seen in the frame.

Boom Operator

Utility is responsible for cable wrangling, batteries, helping the mixer, sometimes being a second boom op

Video Assist helps set up monitor feeds for the mixer

Utility and Video Assist

Read Chapters 3 and 4 Assignment #1

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