Music & sound effects

A finished demo has a soundtrack: a music bed underneath, and sound effects on the actions. Both are part of the recording itself — nothing is added in an editor afterwards. This clip plays its own lesson: everything it names, you hear happen. Sound on.

What it covers

• The bed — one line of direction lays a track under the whole video. It starts at the first frame and loops to fit any length.
• Ducking — when the voice speaks, the bed steps down out of the way, and comes right back after the line. Nobody mixes that by hand.
• The beat grid — tell it your track's tempo (BPM), and moments can ride the music: change the track mid-video and the swap waits for the bar, landing on the downbeat.
• Stop & resume — drop the bed out for a quiet stretch; bring it back when it serves.
• Sound effects — map a sound to clicks or typing once, and every matching action carries it from then on. No per-action work. Bring your own files — short, dry one-shots sit best.
• One-offs — a sound that isn't feedback for an action: a chime on a reveal, placed wherever you point it.
• End on beat — the video doesn't run out mid-phrase; the bed closes its phrase clean — instead of running out mid-bar.

Say it like

You supply the audio — a music track, a few short sound files. Name them and say when to use each; NextDemo places them, nothing is generated.

• "Use dusk-loop.mp3 from the project root as the bed under the whole video."
• "Say 'this is the best part of our product' over the weather widget."
• "Crossfade to victory-lane.mp3 on the downbeat when the dashboard opens — it's 94 BPM, same as the bed."
• "Stop the music while I type the command, then bring it back."
• "Use snap.mp3 when I click the switch, and click.mp3 on the buttons."
• "Play chime.mp3 when the export finishes."
• "End on the beat."