Audio Basics

Session 03

OVERVIEW

• Announcements• Audio basics• Sound dimensions• Digital aspects of audio production• Sound pickup principle• Microphones• Cables and connectors• Definitions• Recording activity• Preview next session

ANNOUNCEMENTS

• 6pm time for rest of semester• Save any work to Documents folder Not desktop (it will be deleted)

• Closing down the Macs– At end of class; quit all applications (not just close window)

• For example Safari menu > Quit

– Apple icon in upper left corner > Shut down (but do Not log out)

• Added links page to http://edt522.yolasite.com– Storyboard and scriptwriting

– More as we progress through course

AUDIO BASICS

• Audible vibrations or oscillations of air

• Sound– Has purpose

– Is organized

– Is wanted

• Noise– Essentially random

– Typically unwanted

• Same audible vibration could be sound today and noise tomorrow

AUDIO BASICS• Clean, clear, consistent, coherent• All connected to reducing noise, acquiring sound• Literal sounds

– Convey a specific literal meaning– Help tell the story by connecting to on-screen visuals

• Even if speaker leaves scene but you still hear voice its connected

– For example, teacher talking and student responding

• Non-literal sounds– Not intended to convey literal meaning– Are deliberately disconnected from on-screen visuals– For example, most musical accompaniment

INFORMATION FUNCTION• Direct address

– Speaker speaks directly to viewer– Talking head– Primarily used to provide information

• Dialogue– Two or more people– Primarily used to communicate theme via question and answer – Interview skills required

• Narration– Supplies additional information/material– Describes screen event or bridges gap for continuity– Often off-screen voice-over– Typically spoken word

SOUND DIMENSIONS• Rhythm

– Pace– Relative to visuals

• Figure/ground– Choosing important sounds to be figure while relegating other sounds to background– Reporter’s voice more predominant than natural, ambient sound in background

• Sound perspective– Matching close-up shots/visuals with “close” sounds – Matching long shots/visuals with sounds that seem from farther away

• Sound continuity– Sound maintains its intended volume and quality over a series of edits

• Listener perception effected by:– Microphone changes from scene to scene– Expectation given the overall aesthetic experience– For example, classroom scenes typical signal to us certain expectations– For example, Wild Kratts boat sound

SOUND DIMENSIONS• Puzzle #1

– Nature scene

– A visual figure/ground task

SOUND DIMENSIONS• Puzzle #2

• Mathematics word problem

• Auditory processing problem– Listener perception and expectation

DIGITAL ASPECTS• Record to digital formats directly

– Via camera’s microphone– Via microphone to computer– Via microphone to digital audio tape – Via microphone to hard disk recorder

• Music– MIDI– Live– CD

• Monitor– Speakers make a big difference– Listening to something on your mobile device is not the same experience as a full stereo with subwoofers– Monitor with headphones while recording (on camera)

• Edit– Software has many features– Editing, splitting, copying, mixing, effects– Clean, clear, consistent, coherent still applies on recording

• Dissemination– Export to file for computer– DVD– Podcast– Web page– App

SOUND PICKUP PRINCIPLE

• Microphones transduce sound waves into electrical energy

• Microphones transform sound into a signal

• Signal made audible through speakers/monitors

• Computers transform into digital

MICROPHONES• Different mics for different purposes

– Find out if your school or organization owns any mics

– Find out what kind, what type of connections at end of cable they have

• Good audio means choose the right mic for the sound pickup task

• Classified by– How well they hear

– How they are made

– How they are typically used

HOW WELL THEY HEAR• Pickup pattern

– Omnidirectional

• Hears equally well from all directions

• Think of mic at center of a sphere

• Sphere represents the pickup pattern

– Unidirectional

• Designed to hear from one direction-the front

• Think of mic at top of heart shape

• Heart shape represents the pickup pattern

• Sometimes called cardioid

HOW WELL THEY ARE MADE• Dynamic

– Uses small coil that moves within magnetic field when activated by sound– Rugged– Works well with close sounds and loud sounds

• Snare drum

– Often have pop filter for close talking phonemes• Go to instructables.com search for microphone pop filter

• Condenser– Uses a moveable plate, a diaphragm, that oscillates against a fixed plate to produce signal– Less rugged, more sensitive to temperature, physical shock– Produce higher quality sounds– Works well with indoor sound pickup of crucial sound– Need a power supply

• Some have battery• Others through console

• Ribbon– Uses a tiny ribbon that moves in a magnetic field– Highly sensitive– Works well for musical recording in highly controlled environments

HOW TYPICALLY USED

• Lavalier

• Hand

• Boom

• Desk and stand

• Headset

• Wireless

LAVALIER

• Lav for short

• Sometimes called lapel

• Small, rugged, omnidirectional

• Voice pickup

• Distance from mic to voice typically does not change

• Good for instructors, talking head, dialog/interview

• If noisy environment surrounding, ambient noise can be picked up

• Attached to clothing means rubbing of clothes if talent moves

• Concealed partially under clothes, in pockets, talent must wear appropriate garments

• Possibly muffled by clothing

HAND• Handled by talent

• Used where talent must exercise some control over sound pickup

– Under normal conditions speak across mic rather than into it

– Reporters, singers, hosts

• Outdoors

• Check action radius of the mic cable

– Will cable get caught on objects in environment

BOOM

• Mic connected to boom

• Boom out of picture

• Suspended by boom

• Often hypercardiod or supercardiod (shotgun) mics used because

• Mic is usually farther away from source than lavalier or hand

• Check the reach of boom before taping

• Check that cable and mic are fastened

• Monitor boom mic with headphones during taping

• Watch for shadows that boom may cast

• You can be the boom and just point a shotgun mic at a person

DESK & STAND

• Mounted on tabletop

• Used for panel shows, public hearings, speeches, news conferences

• One mic per person typically; can share for panels

• Multiple mic interference if positioned too closely– Place individual mics three times as far apart as any mic is from its user

• Tape mics to table; tell guests not to touch

HEADSET

• Sportscasters, singers, live events from field

• Combined with earphones

• Talent can hear the program sound including his/her voice in one ear and instructions from producer/director in other

• Hands free

WIRELESS

• Also called radio mics

• From transmitter to receiver

• Receiver connected to mixer, audio console, possibly camera

CABLES & CONNECTORS

¼” phone jack/plug mono

XLR Connector

1/8”or 3.5 mm mini-plug stereo

CABLES & CONNECTORS

RCA phono plug

MIDI

ADAPTERS of ALL KINDS

1/8” mini-plug to ¼’” phone plug 1/8” mini-plug to XLR

LINE LEVEL

• Line level refers to strength of audio signal

• Most mics are not line level

• Mic level is usually lower than line level– Results in low levels on recording

• Most computer sound cards want line level

• Most mics need pre-amplification using a preamp or mixer to increase pickup

– Mic to preamp to computer– Avoid boosting gain too much– Signal to noise ratio– Gain is

• Preamps range in cost

DEFINITIONS

• Amplification– strengthening of an audio signal for an increase in loudness

• Attenuation– signal loss, a lowering of level

• Gain– How much an electronic circuit amplifies a signal, measured in decibels

• Line level– type of level (strength) of electrical signal used in professional audio equipment

Professional gear is +4 dBu (1.23 volts) and consumer line level is -10 dBV (0.316 volts)

• Mic level– type of level (strength) of electrical signal used in professional audio equipment,

generated by the microphone; about 60 dB lower than line level

PROCEDURES• Plug in your cables/connections

• Turn on preamp if necessary– Some are USB

• Position mics if lavalier or on stand

– Proximity is important

– Hold close to mouth

– Squat down to interview child so visually on level plane

• Prepare to monitor on recording device (camera, mixer, computer) with headphones

• Test mic prior to taping

– Get level

• Do not blow, whistle, tap, whack

• Generally just talk, count

• Remember fresh batteries if necessary

SET UP TODAY• 6 mics

– Shure SM57• Dynamic, unidirectional, cardiod, instrument mic including vocals

– Shure SM48• Dynamic, unidirectional, cardiod, voice and vocal mic

– AudioTechnica shotgun mic• Dynamic, unidirectional• Uses a battery

– StudioProjects Condenser• Requires phantom power from preamp

– 2 lavalier mics

• “Prosumer” mixer

• Handheld mics using XLR into mixer – Wireless going 3.5mm (1/8”) adapter into ¼” phone plug on mixer

• Mixer using XLR output adapted to 3.5mm mini-plug (1/8”) on iMac

• On the Mac– Sound control panel/system preferences set to line in and input level adjusted

• In GarageBand– In Preferences> Audio/MIDI> Input set to System Setting

RECORDING ACTIVITY

• Record voices• Volunteers to read passage• Run through most of the mics

– Once line into computer– Once line into mixer, then into computer

• Selection– Green Eggs and Ham by Dr. Seuss

• Read just your “start with” one time, then your lines of the text then stop• Try to read like you are being recorded, articulate, lets hear every

syllable, use your own rhythm and phrasing• We will listen back for changes in recording level and discuss

NEXT SESSION

• GarageBand intro