# FMOD Parameter Trigger not updating parameter in Unity

**URL:** https://qa.fmod.com/t/fmod-parameter-trigger-not-updating-parameter-in-unity/23415
**Category:** Unity
**Tags:** unity
**Created:** [October 1, 2025, 3:50am UTC](https://qa.fmod.com/t/fmod-parameter-trigger-not-updating-parameter-in-unity/23415 "2025-10-01T03:50:45Z")
**Posts on this page:** 1
**Showing post:** 7

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### Author: ![li\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/li_fmod/32/6577_2.png) [@li\_fmod](https://qa.fmod.com/u/li_fmod)
#### Post date: [November 19, 2025, 4:56am UTC](https://qa.fmod.com/t/fmod-parameter-trigger-not-updating-parameter-in-unity/23415/7 "2025-11-19T04:56:02Z")

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Thank you for providing extra details and the log!

> [@MightyMuso](#):
>
> In this case, PegBasic instances aren’t being instantiated in the traditional sense, they’re preloaded into a parent prefab. The Emitter’s Play() method never runs because the object is never ‘created’, so naturally TriggerParameter() can never find the PegBasic instance.

It looks like the log confirms your findings: the parameter triggers fire before any `EventInstance` exists because `Play()` never runs. Since the pegs are preloaded and don’t hit the usual Unity lifecycle hooks (Start/OnEnable), the StudioEventEmitter won’t play automatically.

> [@MightyMuso](#):
>
> We’re working on a way to fix this that doesn’t require creating every instance of a peg (this would slow down the game significantly), unless there’s a way for Emitters to trigger for objects created at runtime.

Two approaches that might fit your workflow:

- **Trigger a lifecycle:** pool pegs as inactive, set emitter to OnEnable, then `SetActive(true)` when used. This ensures `Play()` happens before you set parameters.
- **Control it explicitly:** from Playmaker or a tiny bridge script, call `emitter.Play()` (or create/start an `EventInstance` directly) and then set the `Perk` parameter, which is commonly recommended for runtime driven behavior. You can find a related discussion here: [Changing a SudioEventEmitter's Event During Runtime - #2 by Leah\_FMOD](https://qa.fmod.com/t/changing-a-sudioeventemitters-event-during-runtime/19532/2)

Hope this helps!

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