Answer: yes — Kling 4.0 generates an audio track alongside the video, including a continuous ambience bed, the specific sounds tied to the action, and a designed ending, all directed through the prompt. What it does not give you is stems, level control, or frame-accurate dialogue sync, so scripted lines still get recorded and placed in post.
That is the honest split: sound design yes, sound mix no. Knowing which side of it your deliverable falls on decides whether the clip is finished when the render lands.
What the audio track contains
- Bed. Room tone, wind, rain, traffic, machinery — the continuous layer under everything.
- Events. The sounds attached to actions: footsteps, a latch, a splash, a landing, a door.
- Landing. The final sound the cut resolves on, which is the part most prompts forget and most edits need.
- No music by default unless you ask; a silent request does not produce silence, it produces association.
What it does not contain
| Kling 4.0 audio | |
|---|---|
| Separate stems | no — one mixed track in the file |
| Level control | no — re-render to change balance |
| Frame-accurate lip sync | no — place dialogue in post |
| Named music tracks | no — genres and tempo survive, licensed songs do not |
| A silent plate with "no audio" | closest is "room tone only", not true silence |
The three cases
Case 1 — the clip is the deliverable. A social spot with ambience and footsteps is finished on render. This is where the model earns its price: no separate SFX pass, no licensing.
Case 2 — the clip needs music. Write "no music", render, then add the track in the edit. Asking for music inside the render means re-rendering to change it, which is the expensive version of a five-second decision.
Case 3 — the clip needs dialogue. Write "no dialogue", render the picture, then record and place the lines. Any prompt-generated voice will be approximately synced, and "approximately" is visible at every close-up.
How to write the audio line
A pattern that survives contact with the model:
Sound: begin with [bed]. At [beat] [event], then [event] as [action].
End on [the small sound the cut lands on]. No music. No dialogue.Two habits make the difference:
- Name the small sounds. "The click of the latch" gets placed; "some sound effects" gets ignored.
- State the absences. "No music, no dialogue" removes the model's two most common inventions.
Cost implications
Audio is included — the per-second price does not change. What changes is the re-render count: a sound-led piece that needs three attempts at the mix costs 3×, so spending two minutes on the sound line is cheaper than iterating on it at 6 credits a second.
| Job | 720p | 1080p |
|---|---|---|
| 5 s with sound | 30 credits | 45 |
| 10 s with sound | 60 | 89 |
| 30 s with sound | 180 | 267 |
When not to rely on generated audio
- Broadcast deliverables with a loudness spec. You need a mix, not a baked track.
- Multilingual versions. One track, one language at most; localisation means re-recording.
- Scenes where music carries the emotion. Generate silent, score in the edit.
FAQ
Can I download the audio separately? Only by extracting it from the rendered file; there is no separate stem.
Does asking for "no audio" guarantee silence? No. "Room tone only" is the closest, and it is still a generated track.
Is audio generated for every Kling model? No — support differs by model and mode; check the controls before budgeting a sound-led piece.
Does audio make the render slower? The clip is one job; the quote covers picture and sound together.
The published motion studies on Callirra's Kling 4.0 page each end with a sound instruction, which is the fastest way to see how far the audio direction reaches.