Decide what kind of audio recording you want to make, how long it's going to be and how many people are needed as vocal talent. If you're recording a story or memoir, you can probably do all of the narration yourself. A radio play, however, will require several participants who can do different voices and accents. The length of your audio production depends on the interest level and attention span of your target audience. A memoir that's going to be listened to by adults, for instance, will be longer than a children's story simply because children have much shorter attention spans. For the purposes of this article, the assumption will be that you're writing a short, radio-style play with six characters, in which you and one member of the opposite sex will divide up the male and female roles.
Come up with a plot that can comfortably fit the time frame allocated for your audio CD. The best plots, whether they're destined for page, stage, cinema or radio, are those that revolve around conflicts involving reward, revenge or escape. They must have protagonists to whom your listeners can relate and antagonists who will zealously throw obstacles in the protagonist's path at every turn to keep her from achieving her quest. Think about events that have occurred in your own life and how these might be adapted to different eras and settings. Examples: a star-crossed romance, competition in the workplace, generational differences, a disastrous vacation.
Make a list of characters for your story. Since your listeners are only going to know them through their voices, their personalities need to be distinctive (i.e., young, old, sophisticated, backwoods). Keep in mind when you start to write your dialogue that men and women express themselves differently and that their education and social status are revealed through grammar, syntax and the complexity of the topics they talk about.
Outline your script before you start writing it. Let's say your audio CD is going to be 15 minutes long. This means your written script will be 15 pages (1 typed page = 1 minute of air time). Since your script will adhere to a traditional three-act structure, this means you'll devote five pages to the first act, five pages to the second act and five pages to the third act. The first act should introduce the lead characters and the conflict and end with a cliffhanger. The purpose of the second act is to complicate the protagonist's problems and end with an even bigger cliffhanger. The third act will resolve the conflict but not before placing the protagonist between a rock and a hard place and forcing him to take the biggest risk of all to finally achieve his goal.
Identify the setting(s) for your audio CD, and think about the noises that are generally associated with them. If the action takes place in a restaurant, for example, there'll be the background sound of patrons and wait staff, the clattering of dishes, the clinking of glasses. If you have a scene transpiring in a forest or at the seashore, there'll be birds, frogs, crickets and weather sounds, such as rain, wind and thunder. An office scenario would have ringing telephones and the sounds of fingers typing on keyboards. A city in the midst of chaos will come alive with the sounds of sirens, screams, helicopters and squealing car brakes. Writing a Halloween story that unfolds in a haunted mansion? You'll want to include creaking doors, chains, baying hounds, eerie laughter and ominous footsteps. Whatever kinds of sounds you need can easily be downloaded for free at websites such as A-1 Free Sound Effects, Sound Effects and Partners in Rhyme (see Resources). In the script you write, sound cues are identified as SFX. Just as the dialogue after a character's name tells your actor when he's supposed to speak, the SFX designation tells you what sounds go where.
Decide how you want to use music in your audio script. Music can do a lot to create ambience before your characters even utter their first lines. For instance, a recording of Vivaldi's "Four Seasons" sets the tone for a classy, upscale setting. In contrast, heavy metal instrumentation with a pulsing bass creates an instant mood of agitation. A child's music box melody can either allude to youthful innocence or a creepy montage about a restless spirit whose life was cut short. Music can also be used in an audio CD as a transitional bridge from one setting or time period to another.
Download a radio script template for free from websites such as Tony Palermo's RuyaSonic (see Resources). While you have a lot of latitude to use any script format you'd like if your CD is just an informal recording that you're doing solo or with a group of friends, the finished product may be something that you'd actually like to pitch to a radio station. If so, it needs to be in a standardized format so that a group of strangers and technicians can easily understand what you intended.
Write your script straight through from your outline. You may want to write all of your narrative/dialogue first and then go back and add in the sound effects and music cues where you want them to take place. During this process, print out copies of scenes, and recruit friends to read your dialogue out loud. It's also helpful to have friends who aren't familiar with the story at all to sit and listen to what's going on with their backs turned to you so that they can't see anyone's facial expressions or gestures. If, for instance, a character shrieks, "Oh no!" in response to spilling grape juice down the front of her dress, a listening audience isn't going to know what just happened unless it's conveyed through dialogue. Example:
AMELIA: Oh no! My beautiful dress!
FRED: It's just a little spill.
AMELIA: It's grape juice, you idiot! It's going to stain!
FRED: Maybe they'll think it's part of the pattern.
AMELIA: It's the shape of Ohio and growing!