Until recently, AI video was silent and you added sound later. In 2026 most leading models generate audio and video together, so dialogue, sound effects and ambience are synchronized with the action. This guide explains how to get good sound out of them.
Native audio vs adding audio later
- Native audio: the model generates picture and sound in one pass. Lip movement, footsteps and impacts line up with what you see.
- Audio-to-video: you supply an existing track (voiceover, podcast, song) and the video is built around it. See how to convert audio into video.
- Post-production: generate a silent clip and add music or voice in an editor. Still useful when you need licensed music or a specific voice.
Which AI video models generate sound?
- Google Veo 3.1: audio is always on for every variant (Standard, Fast, Lite), per Google's documentation.
- Gemini Omni Flash: generates an appropriate audio track by default.
- Kling 2.6, 3.0 and 4.0: native audio; Kling 4.0 adds two-channel stereo and improved lip sync.
- Seedance 2.5: joint audio and video generation up to 30 seconds.
- MiniMax H3: 32 kHz stereo audio with dialogue in 11 languages.
- Wan 3.0: accepts audio as input; Alibaba notes its audio texture is still improving.
Step by step: make a video with sound
- Pick a model with native audio in the TextVidAI generator.
- Write the scene first: subject, action, setting, camera.
- Add an audio line at the end of the prompt (examples below).
- Generate a short test (4–8 seconds) to check voice and sync before longer clips.
- Adjust and regenerate. Change one audio element at a time.
How to prompt audio
Dialogue
Put exact speech in quotes and name the speaker. Google's Veo guide recommends this format: A woman at the bus stop checks her phone and says, "It's ten minutes late again." Add tone and, for models that support it, language and accent.
Sound effects
Describe sounds explicitly: "Glass shatters, then a dog starts barking." Models rarely add specific effects you do not name.
Ambience
Describe the soundscape: "Busy café: espresso machine hiss, low chatter, cups clinking."
Music
Give genre and mood rather than a song name: "soft lo-fi beat, relaxed." If you need a specific licensed track, add it in editing.
Silence
If you plan to add your own voiceover, write "no dialogue, no music, only ambient sound."
Fixing common sound problems
- Clip is silent: check that the model supports audio and that your prompt describes sound.
- Lip sync is off: shorten the line, keep the speaker facing the camera, and avoid fast camera moves during speech.
- Wrong language or accent: state it next to the line of dialogue.
- Unwanted music: say "no background music."
- Voice changes between clips: use the same character description; some models (Kling 4.0, Seedance 2.5, MiniMax H3) accept voice or audio references.
FAQ
Can AI generate a video and its sound at the same time?
Yes. Veo 3.1, Kling, Seedance 2.5, MiniMax H3 and Gemini Omni generate synchronized audio natively.
Can I use my own voiceover?
Yes. Generate without dialogue and add the voiceover in an editor, or use an audio-to-video workflow.
Is AI-generated audio good enough for ads?
For ambience and effects, often yes. For brand voice and music, many teams still record or license audio and add it in editing.
Sources
- Google: Veo 3.1 documentation
- Kling: Introducing Kling 4.0
- ByteDance Seed: Seedance 2.5
- MiniMax H3 model card
Last updated: October 9, 2026.