Radio Sound Effects

A Theoretical Outline

An outline of elementary theory about the use of sound effects in the creation of audio theater.


Sound conveys meaning. Sound stimulates our visual imagination: it creates visual images in our minds. Audio Theater is telling a story by the careful mixing of sounds - both verbal and non-verbal. As one child said, "I like radio because the pictures are better."

Audio is a "hot" medium - that is, the listener's imagination and experience are involved in giving the story depth, substance and meaning.

Sound effects describe the circumstances of a dramatic audio situation. They can be used for such things as setting and place, conveying action, solving certain narrative problems, and evoking characterizations.

Point of View (PoV)

Where the listener is hearing from. Often the PoV is that of the main character. Effects should sound as though they were being heard by that character. An omniscient PoV means that it can change from one character or group to another, or even to a narrator, as necessary.

If the piece's PoV is omniscient, you can use it as a change of scene: for example, by altering the texture of the ambient sound background; or you might have the current foreground change to become background, and begin a new foreground.

I. Elements of Sound Design

  1. Objects - The things we have to work with.
    1. Dialogue
    2. Sound Effects
    3. Music
    4. Silence
  2. Techniques - What we can do with the objects.
    1. Mixing - the combination of..., the balance and control of amplitude of multiple sound elements.
    2. Pace - Time control. Editing. Order of events: linear, non-linear, or multi-linear.
    3. Transitions - How you get from one segment or element to another.
      1. Segue - one element stops, the next begins. "Cut" in film.
      2. Crossfade - one element fades out, the next fades in, they overlap on the way.
      3. V-Fade - First element fades to inaudible before the second element begins.
      4. Fade to Black - V-Fade with some silence between elements.
      5. Waterfall - As first element fades out, the second element begins at full volume. Better for voice transitions, than for effects.
    4. Imaging - Stereo image. Using left and right channel for depth. But don't forget the mono listener. Does it work as well in mono as it does in stereo?
    5. Treatments - or signal processing. See Treatments below.

II. Using Sound Effects

  1. In general, the listener should hear the sound effect before the dialogue or action refers to it, if it is referred to at all.
  2. Usually in a recording studio the object is to reproduce the sound as accurately or as cleanly as possible. In radio theater, and particularly in sound effects, recording technique often depends on the "degradation" of sound. You are changing the sound to establish and maintain the picture you want to create in the mind of the listener.
  3. Sound effects should be used sparingly. Too many effects, or too much of one sound, will alter the attention of the listener away from the story, and will slow the pace of the action.
  4. Sometimes it is better to skip all the active running footsteps, and simply go on to the next dramatic scene of action. "Cut to the chase."
  5. Real sounds are more convincing than synthesized ones. But most things do not make the sound we think they make.
    1. A sound effect most often consists of more than one part - usually several parts. It's like a mini-drama, with a beginning, middle, and end. It is meant to indicate some action or event, and it should follow through to complete that action.
    2. A door opening isn't just one click of the latch. Answering the telephone must be more than the simple and quiet click we actually make picking up the receiver. Rattle, rattle!
    3. Most effects you hear - especially in the movies - are actually the result of at least two people, long after filming, doing something with two or more objects, probably unrelated to what you are supposed to be hearing.
  6. Acoustic Space - what space does it sound like this is happening? Does it match the intent?
    1. Pre-recorded sound effects samples (records and tapes or CDs) are recorded in a particular place and sound environment. This probably is NOT the same "acoustic space" that your actor's are, or where you want them to sound like they are. An effect that doesn't sound like it's in the same place as the actors can destroy the image you were trying to build for the listener. Don't have a person walk outside, and slam a door with lots of reverberations around it.
    2. I encourage you to make and record your own effects. It gives you greater choice of sounds, and better control over them. Record sounds from close up, from various distances, and perhaps even with different microphones. Also, keep all the effects you record. You never know when you might need them again - or someone else will. Most producers have racks of un-catalogued tapes full of sounds they have recorded.

  7. Music follows similar rules to sound effects, and may be used as sound effects.. Sound effects have an action content. Music has a reaction, or internal, emotional content. So, in general, you will most often introduce the effects (action) first, and the music (reaction) after it.
    1. Thematic Music - up front; use for open and close, transitions, under credits, etc. Sets the tone of the work.
    2. Underscore Music - dramatic subtext; match the mood of the piece, but not interfere with the other elements of the sound mix.
    3. A musical "sting" is made up of more than one note, probably more than two.
    4. Music shouldn't be mixed too loudly, or it draws attention to itself, and away from the action. It may also interfere with hearing dialogue or effects. Music in frequencies different from those of human voices, etc., can be mixed louder without interferring, and can be more strongly integrated into the sound collage.
    5. Music is the straightest path to the emotional centers of the mind. Other sounds - dialogue or effects - must be translated and understood first. So, dialogue and effects might be used to set up the situation, and music makes it pay off.

III. Kinds and Categories of Sound Effects.

  1. Real and Unreal Kinds of Sound Effects
    1. Literal Effects - are intended to sound like what it is supposed to be. A kind of literal effect is the "emblematic" or "associative" sound effect. It associates in our minds with specific events, and tells us clearly what is happening. Once established, they can be used again to return to a place, event, or image, easily and quickly.
    2. What are the elements of a sound that create that desired image, or make that particular association? (Running water: add to it the sound of moving a shower curtain, and it is distinguished from brushing teeth or washing dishes.)
    3. Non-literal Effects - are sounds used to indicate an event, without being "like" the actual sound of it. Especially for things that don't really make a characteristic sound: what do ghosts sound like? Or sharks passing under water? Often music will be used.

  2. Categories of Sound Effects
    1. Ambiences (atmospheres or backgrounds) - Provide a sense of place where, and perhaps of time when, events occur.
      1. Background sounds which identify location, setting, or historical time. "Every place on the planet has it's own voice. And that voice changes with the time of day and time of the year."
      2. Interiors are usually reverberant ("wet") to some degree, indicating the size of an enclosed space.
      3. Exteriors are usually flat, layered elements of sound in a non-reverberant ("dry") space. Even voice characteristics are different outside.
      4. A good unedited background can cover a choppily edited dialogue, making it sound real and continuous. Ambiences can be done with continuous tape carts, tape loops, long recordings, or other means.
    2. Discrete (spot) Effects - Indicate individual events; what, how, and how much.
      1. Brief individual effects, or composite of effects, specifically placed and timed for a single action.
      2. Foley Effects are incidental naturalistic sounds of movement and business, recorded to match the action. Foley effects are Spot effects, but spot effects are not always Foley effects. (Named after Jack Foley, a Second Unit director for Universal Studios in the 1940's. Which makes "Foley" really a part of Film Sound, and radio guys prefer to be called Sound Effects Artists.)
      3. Some Foley effects can be recorded live, on the voice track. Having the actors themselves make the sound can aid in timing the effect, and it can help the actor's voice convey the movement. It can also complicate the recording session.
      4. Many spot effects can be made with the mouth, the hands, or with small noisemakers.
    3. Wallas - Crowds. "Walla walla" of many people in a crowded situation, without specific voices or words being distinguishable.
      1. Bar wallas differ from Ball Game wallas, and differ from concert audience wallas, etc.
      2. Bars, for example, are a difficult environment to control - like what music is being played, or how loudly, or when distractions occur. You may have to record a lot of this background to be able to find enough for you to use.
      3. Often a foreign crowd scene works well because you'll never have English words popping up when you don't expect or want them to.
    4. Dialogue - Don't forget that dialogue is sound, too. The character of the voice indicates a lot about who the character is. Also think about vocal contrast; choosing voices that differ enough to be easily identified and differentiated by the listener.
    5. Silence. A dramatic element. It can be very loud.

IV. Layering

  1. Mixing two or more sounds together to create a combined sound that is more than each of the individual sounds alone. Often consists of non-specific background with added "associative" sounds to help identify or differentiate specifics.
    1. Restaurant scene might begin with voices and kitchen noises in background, then add foreground plates, silverware, and pouring of wine begin to define what kind of restaurant we're in.
    2. Wilderness scene might have birds and insects, but you add distant wolf howls, or close up footsteps, and chain saws, and the story already begins to unfold without any dialogue.
  2. Starting with a mechanical sound, then layering in the roar of a lion or elephant trumpet adds an organic life to the sound, making it more immediate or more intimate than the mechanical sound alone.

V. Treatments

  1. Things you do to sounds; effects generators and degenerators.
  2. Treatments with sound or signal processors, allow you to alter sounds in three domains:
    1. Amplitude or Volume Domain. Volume control.
    2. Spectral Domain - e.g., equalizer.
    3. Time or Phase Domain - e.g., Reverb or Delay.
      1. Time domain is the long view.
      2. Phase domain is the short view.
    4. Combinations of these three.
  3. Equalizer - Alters the "tone" of the sound. It lets you choose which frequencies (high, low, or mid-range) of the sound to enhance or inhibit. You might equalize a background sound, deminishing frequencies in the vocal range, to allow the ambience to be louder without interferring with the dialogue or other spot effects. (Might be used for vocal contrast in a 'thought' voice filter, or a telephone or mechanical voice.)
  4. Pitch Control - Slow down or speed up the sounds. A "Veri-Speed" alters the speed of the tape through the recorder, effecting the speed of the recording directly, or playback inversely. Now done digitally with software effects modules.
    1. Gives you control over some aspects of the sound, allowing you, for example, to use the same effect over again without it's being recognizable, or to alter the frequency or duration of the sound to fit the situation.
    2. With software plugins the Pitch and Duration of any sound can be modified separately, allowing you to lower a sound without making it longer, or raise the pitch without making it shorter.
    3. Often used to fit music or an effect into a specific timed event.
  5. Worldizing - Playing sounds back on speakers, and recording them again with microphones, makes a significant change in the texture of the sounds. For example, play back a room ambience at double speed, recording it with a microphone. The new recording, played back at normal speed, will at least double the "size of the room" sound.
  6. Digital Sampling - A "sample" is a sound recorded as computer-readable numbers, rather than analog symbols. Using the computer, those sounds can easily be altered, or the sound can be reproduced very precisely and repeatedly. Sampling can be useful for the above reasons, but once altered, the effects are often not as convincing as real unmodified sounds.
  7. Other treatment devices
    1. Reverb and Delay - repetition of an original sound.
      1. Delay, or echo, refers to a discrete repetition of a sound, so that you hear the original sound more than once.
      2. Reverberation refers to the persistence of sound in a room after the original sound has ceased, caused by continuous sound reflections so close together that they seemingly merge into a single continuous sound.
    2. Chorusing, Flanging, and Phasing - special effects in which the original sound is combined with a delayed repeat signal (or signals), to create wavy multiple voice effects. Sometimes the processed signal is also fed back into the loop. Phasing mixes an out-of-phase repeat signal with the original. (Often used for alien voices in science fiction works; too often, in fact, to the point of a cliché.)
    3. Binaural recording - the way the human ears actually hear. It uses a model human head with an omnidirectional microphone in each sculpted ear. Very directional. Meant to be heard with headphones to get full effect.

Created for a college level class in radio production, unit on radio theater. Material assembled from a variety of sources, especially from the following people and many more at the Midwest Radio Theater Workshops: David Ossman, Tom Lopez, Skip Pizzi, Sue Zizza, Steve Donofrio, Charles Potter, Marjorie Van Halteran, and Richard Fish. A version of this outline was reprinted in Radio World magazine, June 1998, P. 52. It is also often used at the Midwest Radio Theater Festivals annual workshops.

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