# Using event property to switch BGM ends up playing all BGM cases
**URL:** https://qa.fmod.com/t/using-event-property-to-switch-bgm-ends-up-playing-all-bgm-cases/15344
**Category:** FMOD Studio
**Created:** [December 27, 2019, 10:45pm UTC](https://qa.fmod.com/t/using-event-property-to-switch-bgm-ends-up-playing-all-bgm-cases/15344 "2019-12-27T22:45:23Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@clpsplug](https://qa.fmod.com/u/clpsplug)
#### Post date: [December 27, 2019, 10:45pm UTC](https://qa.fmod.com/t/using-event-property-to-switch-bgm-ends-up-playing-all-bgm-cases/15344/1 "2019-12-27T22:45:23Z")
I have two versions of background music. Which will be played is controlled by a certain boolean flag.
I tried to use properties for an Event to do this. The bool property in the event is supposed to be linked to this boolean flag on runtime.
However, I ran into an issue with the following setup:
I have two separate audio files for both versions of the music, both properly loop-processed.
I added a boolean parameter, and FMOD Studio will now show me a tab with the name of the said parameter.
In this tab, I create an audio track and place the two files to the ‘False’ and ‘True’ sections.
This setup indeed allows me to play different tracks under the same event name, but I noticed that when I flip the flag while the event is playing, the version of the music on the flag state I flipped into starts to play **on top of** the already playing one.
This is not what I want. When the flip occurs, the music that is playing **must stop** - in other words, I want them **monophonic.**
I tried selecting both regions in the ‘True’ ‘False’ sections and set the Polyphony to “1” in the “Trigger behavior” settings, which did not do what I wanted.
I haven’t been able to spot the feature to do this kind of thing. What is the correct way to achieve this stuff?
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### Author:  [@alexzzen](https://qa.fmod.com/u/alexzzen)
#### Post date: [December 27, 2019, 11:02pm UTC](https://qa.fmod.com/t/using-event-property-to-switch-bgm-ends-up-playing-all-bgm-cases/15344/2 "2019-12-27T23:02:05Z")
Make sure the Cut mode is activated for both instruments/files:
Tip: if you need a smooth fade in and out when switching you can add an AHDSR modulator to the Volume property of the instruments 😊
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### Author:  [@clpsplug](https://qa.fmod.com/u/clpsplug)
#### Post date: [December 27, 2019, 11:03pm UTC](https://qa.fmod.com/t/using-event-property-to-switch-bgm-ends-up-playing-all-bgm-cases/15344/3 "2019-12-27T23:03:23Z")
That was exactly what I needed. Thank you 🙂