After my  iPad updated to iOS 14.6 a problem arouse. After about 3 to 5 minutes the audio broke up and started to crackle. The degree of break up varies, it might be slight or very pronounce, but when present it can be amplified by scrolling the screen up or down.

On my iPhone iOS 14.4.2 all works normally.

Either something went wrong with the update or iOS14.6 is at fault.