Raspberry Pi 5 + PiSound fan noise

Hello,

I use a Raspberry Pi 5 with PiSound (newest version compatible to Pi 5 with active cooler) and Modep and want to use it with my SY-1000 with VST Instruments.

My main Problem is that there is always a background noise on the audio signal coming from the active cooler on my Raspberry.

Have anybody an idea to get rid of the noise without disable the fan? Any passive cooling case that will fit or some sort of spacer or shielding?