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How to Write Sound Effects Into Audio Drama Scripts — Complete SFX Notation Guide

Sound effects are not an afterthought in audio drama — they are half the storytelling. A door creaking, rain drumming on a window, a heartbeat rising in tension: these sounds place the listener inside the world. But if they're not written clearly into the script, they get missed, improvised poorly, or become a source of confusion between the writer and the sound designer.

This guide covers the professional standard for notating sound effects, ambient sound, and music cues so that anyone — from a solo podcast producer to a full production team — can execute your vision accurately.

The Three Types of Audio Cues

Before getting into notation, it helps to understand the three distinct categories you'll be working with:

• SFX (Sound Effects): Specific, discrete sounds — a gunshot, a phone ringing, footsteps on gravel, a glass shattering.
• AMBIENCE / BG (Background/Atmosphere): Continuous environmental sound that establishes location — city traffic, a crowded restaurant, wind through trees, a ticking clock.
• MUSIC: Score or source music — whether underscore that runs beneath a scene or diegetic music (music that exists in the story world, like a radio playing).

Each needs its own notation style so the production team can identify them instantly on the page.

Standard SFX Notation Format

The professional standard — used by BBC Radio Drama and most major audio drama productions — places sound cues in their own line, in capitals, and clearly labelled. Here is the basic structure:

Notice: SFX lines are capitalised, labelled clearly, and placed before the dialogue they precede or accompany. Never bury a sound cue inside a dialogue line or stage direction.

Writing Ambience and Background Sound

Background sound establishes where a scene takes place. It should appear at the start of each new scene, and any time the environment changes significantly mid-scene.

Music Cue Notation

Music cues require the most detail in the script — the writer should specify whether it's underscore, source music (heard by the characters), and roughly what emotional quality is needed. Leave the specific track to the composer or sound designer, but give them clear direction.

For source music — music the characters can actually hear — mark it clearly:

Quick Reference: Notation Cheat Sheet

Type	Label	Example
Discrete sound effect	SFX:	SFX: PHONE RINGS TWICE. PICKED UP.
Environmental background	AMBIENCE:	AMBIENCE: HOSPITAL CORRIDOR. DISTANT PA ANNOUNCEMENTS.
Scene-setting background	BG:	BG: OPEN OCEAN. WAVES. SEAGULLS DISTANT.
Score music	MUSIC:	MUSIC: MELANCHOLY PIANO. FADES UNDER DIALOGUE.
Heard by characters	MUSIC (SOURCE):	MUSIC (SOURCE): TV NEWS IN ADJACENT ROOM.
Sound fade out	SFX:	SFX: RAIN GRADUALLY FADES.

Common Mistakes to Avoid

• Don't over-specify music. "MUSIC: SAD VIOLIN IN D MINOR AT 72BPM" is micromanaging. "MUSIC: GENTLE, MELANCHOLIC UNDERSCORE" gives the composer room to work.
• Don't forget scene transitions. Audio drama has no visual cut — a transition sound or music sting is how listeners know a new scene has begun.
• Don't assume silence. Dead air is disorienting in audio. If you want a pause, write it: "SFX: SILENCE. BEAT. THEN—"

Scene Transition Conventions

Every scene change needs an audio transition. Common conventions:

• Music sting: A brief music cue that signals a scene change — "MUSIC: SHORT STING. FADES."
• Ambience crossfade: One environment fades out as another fades in
• Hard cut: Abrupt silence followed immediately by new ambience — effective for dramatic effect
• Narrator bridge: A narrator line over neutral ambience connecting scenes