Audio Console Commands

When debugging games or other projects in Unreal Engine, it can be helpful to send commands to your game or the editor directly while it is running. This is especially true for audio. If you are trying to trace a bug that only occurs in narrow or unknown circumstances, console commands can help by enabling or disabling specific functionalities, or by altering a significant parameter in real time.

How to Use the Console

By default, the Command Console is included in the Bottom Toolbar. It is located at the bottom of the Unreal Editor window. You can jump directly to the Command Console entry field by pressing the tilde key ( ~ ) on the keyboard. Note that on British English keyboards, the key used is the grave key ( ` ).

If the tilde key does not open the console, or if you want to use a different key, you can change your keyboard bindings by going to Project Settings > Engine > Input > Console Keys.

When using the console commands, you may also want to open the Output Log. Click the shortcut located to the left of the Command Console. Pressing the tilde key ( ~ ) twice will open the output log drawer as well. This can be also set at Window > Output Log.

Most audio console commands involve setting a given console variable (CVar) to a desired value, through the syntax [CVar name] [Value].

For example, to debug a sound mix, you would set the CVar au.Debug.SoundMixes to true using the command au.Debug.SoundMixes 1 in the console, where 1 = true.

You can also find more information about the usage of a given CVar by entering the command [CVar name ?].

Commands that you type into the console will affect your editor in real time. Console commands can be executed from within the game, from within the editor, or, if the game has been started, by using the -server switch from the server's console.

Common Audio CVars and Uses

With the exception of a handful of older functions, console commands and variables that are audio specific have the au. prefix. Because the console supports autosuggestion, you can get a list of available commands by typing au. in the console and scrolling through the listed commands.

• au.Debug.SoundMixes — This variable, when set to 1, provides information on the currently active sound class mixes. As sound mixes are objects that can impact many sounds in the level at once, glitches with them can be hard to trace. By displaying information on sound mixes, it is easy to tell if any unexpected sound mixes are getting triggered, a sound mix is failing to be pushed and popped off the sound mix modifiers list as expected, or multiple instances of the same mix being active simultaneously. This is often a good first step if attempting to debug a situation such as a single class of sounds suddenly becoming inaudible.

• au.DumpActiveSounds — When set to 1, this variable provides a list of all sounds currently playing. You can use this to narrow down possible sources of errors for issues that sound identical to the human ear, but have different causes. For example, if a sound can no longer be heard, dumping active sounds can clarify whether it is an issue of a sound not being played or if the sound is playing at an inaudibly low level. Similarly, it can help distinguish between loud sounds that are the result of volume modifiers set to unreasonable volumes, and loud sounds that are the result of multiple instances of the same sound playing simultaneously which you might perceive as one very loud sound.

• AudioMemReport — Type the AudioMemReport command without a value (not required) to generate a detailed document on the memory usage of active sound objects. This is useful for tracking down unexpectedly large amounts of memory usage in the audio system. It is also useful for general audio optimization.

Audio Console Commands

Use the commands below to debug the Unreal Audio Engine. Where applicable, the table also indicates the deprecated command that a new command has replaced.

In most instances, enablement and disablement can be set with 1 or 0, on or off, or true or false (on/off and true/false are case sensitive).

The thing to keep in mind is that if 0 = false (disabled) and 1 = true (enabled), then with a command like au.DisableDeviceSwap, where the action of the command is to disable, then the true setting would be the enabling of the action of disabling. This means that to turn this feature on, you would enter au.DisableDeviceSwap 1.

Older Audio Console Commands

The commands below are included because some users may still employ them, and because they do have functionality.

However, these commands do not have any input arguments, and they do not auto-fill the way the newer audio console commands do.