What Unity can do with audio clips on its own

Unity imports audio, compresses it per platform and plays it, but it has never had a built-in waveform editor. What it does have is a set of tools that change how a clip plays without changing the file, and more recently an AI Assistant that can create edited copies. Here is what each one does, from Unity’s own documentation.

Overview

Facts as stated in Unity’s documentation on the date above.

Import settings

The AudioClip import settings decide how Unity stores and loads a clip: Force To Mono, Load In Background, Load Type, Compression Format, Quality, Sample Rate Setting and Preload Audio Data. None of them trims or fades the sound, and Unity never changes the source file on import.

The Normalize checkbox is easy to misread. Unity’s documentation says it applies during the Force To Mono mixdown: after mixing to one channel, the signal is peak-normalized. A stereo clip without Force To Mono is not normalized at all. The Audio Normalize Effect, which ranks first when you search for normalizing audio in Unity, is something else: an Audio Mixer effect that changes gain while the game runs.

Timeline

An audio clip in a Timeline has a Clip In value that skips the start of the file, a length you trim by dragging its edge, ease in and out curves for fades and crossfades, a speed and a volume. Unity’s Timeline documentation calls trimming non-destructive: nothing is written back to the file. That is ideal inside a cutscene. It does not help when the same clip also plays from a script, an animation event or a UI button, because those still play the whole file.

Scripting

AudioSource can start a clip at any position and stop it at an exact time:

• AudioSource.timeSamples sets the start position in samples. Unity notes that AudioSource.time can be imprecise on compressed clips, so prefer timeSamples.
• AudioSource.PlayScheduled starts playback at an exact DSP time, which Unity describes as the preferred way to stitch clips, and SetScheduledEndTime stops it at an exact time.
• AudioClip.GetData and SetData read and write samples in memory. They need clips that are decompressed on load, do not work on streamed clips, and only change the clip in memory. Unity’s AudioClip API has no method to save a file.

This works well when one component owns a sound. It spreads timing values across scripts and prefabs, though, and every new place that plays the clip needs the same offset.

AI Assistant

Unity’s AI Assistant can edit audio clips from a prompt: remove silence at the start and end, trim a time range, change the volume and make a seamless loop. Each edit creates a new clip, so the original stays. When we checked, the audio editing documentation was for a pre-release package (2.19.0-pre.2) that also needs the Unity AI Generators package, and the Assistant requires Unity 6.3 or 6000.0.76f1 or newer. Each Assistant message spends Unity Credits from a Unity AI subscription’s monthly allocation.

If you already use Unity AI, the Assistant is a quick way to make a one-off edit by describing it. Audio Tools covers the same edits and more, including seamless loops, without a subscription and back to Unity 2022.3. It shows the waveform, so you choose the exact cut instead of describing it, and it applies the same settings to a whole folder in one pass.

When to edit the file instead

Edit the file when a clip plays from more than one place, when you want to see and hear exactly what you are cutting, or when the fix belongs to the sound itself: a click at the end, a quiet recording, a silent start, a seam in a loop. Audio Tools does these edits in the Editor, for one clip or a folder, and writes new WAVs next to the originals. For repair such as noise reduction or equalization, Audacity is the better tool.