Hi @Sakku tatsainyo ,
I found a few threads with similar issues; take a look at them:
https://steamcommunity.com/app/1761390/discussions/0/5363238800593536947/
https://steamcommunity.com/app/1761390/discussions/0/591761524439174017/
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So, the first thing I would check is whether all your audio devices are using the same default format. Go to Settings → System → Sound → More sound settings → Playback, select each audio device you use, open Properties → Advanced, and check the Default Format. As a first test, I would recommend using 16 bit, 48,000 Hz or 24 bit, 48,000 Hz on all devices.
If one device is configured for 44.1 kHz and another for 48 kHz, switching between them may cause audio resampling or compatibility issues, which could potentially contribute to freezes or stuttering in Mega Mix+.
The second thing I would try is disabling all audio enhancements. In the properties of your playback device, set Audio enhancements to Off. If you are using features such as Spatial Sound, Dolby Atmos, DTS, Nahimic, Sound Blaster effects, or similar audio-processing software, temporarily disable those as well. These additional audio processing layers can sometimes cause compatibility problems with specific games or audio drivers, so disabling them is a useful troubleshooting step.
The third thing I would check is the Windows App volume and device preferences settings. Go to Settings → System → Sound → Volume mixer and look for the option to Reset sound devices and volumes for all apps to the recommended defaults. This is particularly worth trying in your case because you frequently switch between different audio devices and also play different games using different outputs. Windows can maintain separate audio settings for individual applications, and resetting these settings may resolve an incorrect or corrupted audio-device assignment for Mega Mix+
Let me know how it goes
Elvis