Adding Voiceover to a Slideshow or Presentation

A narrated slideshow has a reputation for being dull, and it is mostly earned. The usual failure is a speaker reading the text on the slide aloud while the viewer reads it faster, which leaves them waiting for the voice to catch up. A narrated presentation that works treats the slide and the voice as two different channels carrying two different things, and it is a skill you can learn in an afternoon.

This guide covers how to script, build and time a narrated deck so that the voice adds to the slides rather than repeating them, whether you record it yourself or generate the narration.

The golden rule: do not read the slide

Viewers read faster than anyone speaks. A slide full of text read aloud forces them to either read ahead and ignore the voice or wait. Neither is good. Put the key point on the slide, in a few words, and let the narration explain, expand and give the example. The slide is the headline and the voice is the story.

Write the script slide by slide

Treat each slide as a unit with its own paragraph of narration. Write the paragraph as a few spoken sentences, aim for between fifteen and thirty seconds, and mark where each slide change falls. A slide that stays on screen for over a minute starts to feel frozen, and a slide that flashes by in five seconds does not give the viewer time to look. Fifteen to thirty seconds is a reliable range for most content.

Time the slides to the voice

1. Generate or record the narration for each slide separately, or mark the slide changes clearly in a single file.
2. Check the length of each section.
3. Set each slide to stay on screen for its section's length, plus a half second.
4. Add a short pause before each slide change, so the voice finishes before the picture moves.
5. Play the whole thing through, and adjust any slide that feels rushed or stuck.

Keep the visual interesting

A static slide is a still image, and a still image held for twenty seconds asks a lot of a viewer. Small touches help: reveal a bullet point as the narration reaches it, move from a full picture to a close-up, or cut to a different image partway through a long explanation. You do not need elaborate animation. You need enough change that the picture seems to be keeping pace with the voice.

Choose a suitable voice

For a presentation, a clear, even and unhurried voice is the right choice, the same as for a tutorial. The audience is following an argument or an explanation, and the voice should stay out of the way. If your deck has an informal tone, an equally informal voice works, but keep the pace steady.

Export for the place it will be seen

Most presentations are shown at 1920 by 1080, which matches the slide format. If the deck will be shared on a platform, export at that resolution, at a modest frame rate such as thirty, since a slideshow does not need more. A low bitrate is usually enough for a slideshow, because most of the picture does not change, and the file will be small as a result.

Add subtitles. A narrated presentation is often watched in a meeting, on a train or at a desk with the sound low, and subtitles let it be followed without audio at all.