---
title: Audio effects and mixing
description: "Ask for a mix in symptoms rather than in filters — make music step out of the way of narration, clean a voice, and know which requests have no honest answer."
---

The last chapter gave your video a voice. This one makes the voice and everything
around it *listenable*.

Audio work is where prompts go wrong in a specific way: it is tempting to name
the machine. "Add a high-pass at 80 Hz with a Q of 0.7" is a real instruction, and
it is worse than the request that produced it, because it commits you to a fix
before anyone has established the problem. The mix is stored as effects on each
track — filters, dynamics, character, space, and envelopes that move any of them
over time — and the agent reaches into that toolbox for you. Your job is to
describe the symptom accurately.

## Say what it sounds like, not what to add

Every effect in the rack exists to answer a complaint. Name the complaint.

```text
The narration sounds muffled, like it's behind cardboard. Fix it.
```

```text
The voice sounds amateur — clean it up but don't make it sound processed.
```

```text
There's a hum under the interview audio the whole way through.
```

Each of those lands on a specific, small change: a cut at 250 Hz, the
`voice-clean` chain, a high-pass under the voice. You do not have to know which —
and if you name the wrong mechanism, you get the wrong mechanism applied
confidently.

This matters more than it does for picture work, because **you can hear a mix and
the agent cannot**. A prompt describing a sound is evidence. A prompt naming a
filter is a guess wearing evidence's clothes.

## The one request worth learning by name

Music under narration is the single most common audio problem, and the reflex fix
is wrong.

Ducking the whole music track works and costs the music all of its presence for
the entire voiceover — it goes limp for as long as anyone is talking. The voice
does not need the whole spectrum, though. It needs the few bands it actually
occupies. Taking only those out of the music is called a **carve**, and it keeps
the low end and the top, so the bed is still music while the voice stays
intelligible.

Ask for it in those terms:

```text
Put the music under the narration properly — carve it so the voice stays clear
without the track going limp.
```

```text
The music is fighting the voiceover. Make room for the voice in the music
rather than just turning the music down.
```

Two things are worth knowing so you can judge the result:

- **It follows the speech.** Silence leaves the music alone; a loud passage pushes
  it to full depth. It is not a fixed dip held through every pause.
- **It lives on the music**, and names the voices it makes room for. If someone
  tells you they carved the voice track, that is a bug rather than a taste
  decision.

If it comes back and the music sounds *hollow* rather than simply quieter, say so
in exactly that word — it means the depth is too high, and it is the one failure
mode with an obvious sound:

```text
Too far — the music sounds notched now. Back it off.
```

## Ask for levels before asking for more depth

A carve cannot fix music that is simply louder than the voice. When narration is
buried, the useful instruction is about **level**, not about spectrum:

```text
Check the actual loudness of the voiceover against the music before touching
the carve — the voice may just be quieter than the bed.
```

Machine-generated speech commonly arrives far below a mastered music track. That
gap is arithmetic, not taste, and no amount of carving closes it. Asking for the
measurement first turns one round of guessing into a number.

## Group the things that belong together

Five narration clips want one set of effects, one fader, and one mute — not five
copies that drift apart as you edit. Say so:

```text
Group all the narration clips as one voiceover group, then carve the music
against that group.
```

That phrasing is worth the extra clause. A carve pointed at individual clips has
to list every one of them, and it stays right only until you add another — the
sixth clip plays outside the carve's awareness and the music silently fails to
duck under it. A carve pointed at a *group* picks up whatever is in the group at
the time it runs.

Use groups for sound effects too, when there are more than a couple. One place to
turn all of them down is worth more than precise individual levels you will never
revisit.

## Ask for movement when a static setting will not do

Anything that should change over the video's length is an envelope, and you ask
for it by describing the shape in time:

```text
Fade the music out over the last three seconds.
```

```text
Bring the ambience up while the wide shot is on screen, then pull it back
under the interview.
```

One caveat worth carrying: a few effects cannot move over time at all — the
compressor, limiter, gate, bitcrush, and pitch shift are configured whole rather
than knob-by-knob. If you ask for a compressor that tightens as a scene builds, the
honest answer is a level stage moving in front of it instead. An agent that
quietly writes an envelope on one of those has written something inert, so if a
requested change does nothing audible, that is the first thing to suspect.

## Three requests with no honest answer

Naming a gap is more useful than accepting the nearest preset and calling it the
thing.

**De-essing.** Sharp `s` sounds need a detector faster than anything in the
toolbox. The nearest fix is a narrow cut in the 5–9 kHz range, swept to find
where that particular voice spits. It is always on, so it costs a little air on
every word. That trade is usually worth it — but ask for it knowing it is a
trade:

```text
The s sounds are spitting. I know there's no real de-esser — put a narrow cut
where this voice actually sibilates and tell me what it cost.
```

**Noise removal.** A gate closes the gaps between phrases; the hiss *underneath*
the words is untouched by anything available. A source with audible hiss needs a
better source, and an agent telling you so is being accurate rather than lazy.

**Matching one voice to another.** There is no match-curve tool. Two takes can be
brought closer by hand with an EQ, which is predictable in a way a derived curve
would not be — but it is hand work, and worth asking for as such.

## Describe the whole mix once, at the end

Individual fixes accumulate into something nobody has judged as a whole. One
closing instruction is worth more than three more adjustments:

```text
Render an audio-only pass and check the mix end to end: voice clear through
the loudest musical moment, effects where the action is, nothing surprising
at the open, and the music finishing on purpose rather than at the file edge.
```

Audio problems are easier to notice when the picture is not competing for
attention. Listening once without watching catches things twenty prompt rounds
will not.

*Next: [Design systems and brand](/prompting/design-systems) — pointing the agent
at a source of brand truth instead of describing a vibe.*
