iPad Air 4 & latest iOS 15 Screencast via QuickTime Player and USB-C connection

Hi there,

I have a problem while recording on a Mac the screencast of my iPad Air 4 (latest iOS 15) via QT and other applications using the USB-C cable that came with the iPad. There is always an electrical buzz that happens randomly in the first 30 seconds and ruins the audio/video recording. This can be clearly heard and also seen in any audio editing software.

I connect the iPad, open QT, choose "New Video Recording", select iPad for both A/V sources, leave the volume down and pressing rec

I tried almost everything from forcing an iPad restart, closing all apps, disconnecting all the devices from my Catalina MacBook Pro 15 2017, changing usb ports on the Mac, deactivating BT & WiFi, deactivating background use for all apps...nothing worked and the buzz is still there, as you can see from the image. It shows a click generated by GarageBand and also a big wave fr the buzz. Tried several times with different conditions as I said, the result is the same.

In the end I took an iPad Air 2 with still iOS 14 and everything worked as expected.

I also have a friend with the same problem but on an iPad Pro and a Mac with Big Sur.

Here's the pic of the buzz:

Any advice or help really appreciated.

Cheeers

Claudio