Sound in an environment

• Sound wave– Compression / rarefaction

• Frequency / Measured in hertz• Amplitude / Measured in decibels (db-spl)

– AM/FM, kHz / MHz (r.f.) • Attack/sustain (internal dynamics)/decay -- sound

envelope• Acoustics / Psychoacoustics / binaural hearing• Absorbed / Reflected• Direct / Indirect (echo & reverberation)

Some issues with sound

• Dynamic range – lowest to loudest sound level range• Equal loudness principle--depending on loudness we don’t

hear low and high frequencies as well as we hear middle• Masking--Hiding of some sounds by other sounds by other

sounds when each is a different frequency and they are presented together. Loud over soft / lower-pitched over higher

• Acoustical phase--the time relationship between two or more sound waves at a given point in their cycles

• Timbre--a sound’s unique tone quality or tone color

Studio / Facility Sound Design

• Ergonomics – human element in designing room• Sound Absorption and Reflection• Diffusion--scattering of sound waves• Diffraction--spreading or bending• Resonance--vibration of an object at the same

frequency as the original body’s frequency• Lively or Dead Room• Isolation

Sound Frequency Spectrum

• Bass– Low bass, 1st & 2nd octaves, 16-64 Hz– Upper bass, 3rd& 4th octaves, 64-256 Hz

• Midrange– 5th, 6th & 7th octaves, 256 - 2,048 Hz– Upper midrange: 8th octave, 2,048 - 4,096 Hz

• Treble– 9th & 10th octaves, 4,096 - 16,384 Hz

Analog / Digital

•  When the true curves and nuances  of a sound wave are encoded onto  the recording medium, like tape, you have an analog recording

• Digital recording samples the audio waves and encodes the information into binary code to represent the waveform.

Digital vs. Analog Recording

• Analog: frequency is the time component and amplitude is the level– (frequency, cycles per second)– (amplitude = loudness)

• Digital: sampling is the time component and quantization is the level.– (sampling, like 44.1 kHz)– (quantizing, like 8 bit word / 16 bit word)

Digital Recording

• Sampling: takes periodic samples (snapshots, voltages) of the analog signal and converts that information into digital data

• Sampling frequency: the rate at which the signal is sampled: 44.1 kHz, 48 kHz

• Think of film at 24 fps – each still frame is a ‘sample’ (snapshot) of information in 1/24 of a second

Digital Recording• Quantization: how many ones and zeroes to

represent each sample• A quantity expressed as a binary number is called

a digital word.• 10 is a 2-bit word, 101 is a 3-bit, 1010 is a 4-bit

etc.• The greater the number of the quantizing level

(10010110 an 8 bit vs. 10, a 2 bit) the more accurate the representation of the analog signal.

Signal Processing

• ‘DSP’ (enhancement)

• Bass roll off

• Compression

• Limiter

• EQ (graphic, parametric)

• Reverb unit

Mics -- Review Sound

• Sound Frequency Spectrum– Bass, midrange, treble

• Frequency / Hertz• Amplitude / decibels• Acoustics• Direct / indirect sound

– Echo / reverberations

More issues with sound

• Sound envelop -- attack sustain decay– Attack, initial decay, sustain, release

• Velocity--speed of the sound wave (examples)– 1,130 fps at sea level– 11,700 fps in wood– 18,000 fps in steel

Microphone Directional Patterns

• Omnidirectional / nondirectional

• Unidirectional / Directional/ cardioid– Super, hyper, ultra

• Bidirectional

Main polar patterns

• Omni / nondirectional

• Bi-directional / figure 8

• Unidirectional / directional / cardioid

Cardioid range• Cardioid

• Supercardioid

• Hypercardioid

• Shotgun mic is hyperdirectional

• Phase cancellation

Professional Mic types

• Moving coil/dynamic

• Ribbon

• Capacitor/condensor

• Transducer – changes energy from one form to another – in this case sound waves into an electrical current

More about mics and sound

• Close vs. distant miking– Cross-pair, mid-side as some distant miking approaches– Close mic speakers on camera / filmmaking wide shots

must do ADR

• Wide response – range of frequencies the mic will pick up

• Flat response – accurately recreates frequencies• Colored response – changes frequencies (lavaliere

boosts high frequencies, for example

Close / distant miking

• All foreground audio is close-miked

• Background (walla, nat sound) audio is distant miked

• ADR compensates for long shots, actors re-record and new dialogue is processed and looped in

• Showing / not showing the mic

Common mic types

• lavaliere

• headset

• Handheld (stick)

• studio/boom mounted

• TV boom types / largest to smallest– Perambulator boom, giraffes, fishpole

• PZM (boundary mic) #

Miking applications

• Movie / TV show scene– Boom pole, ADR (how done)

• News anchor / reporter

• Talk show host

• Play by play announcer

• DJ / audio spot production

• Orchestra on a stage

Movie sound

• Ambience– Walla

• Foley– Foley stage, foley artists– Ben Burtt / Sound Design

• Score

• Layering

• Dolby Surround ###