Hi, I use 60 BPM - Metronome YouTube to optimize Sync of different Receivers by my hearing and changing Monitor Delay.
It seems that hard Metronome Beats are dampened on A1 driving a Bluetooth Amplifier to my Box.
The other channels are not dampened, when a Windows Notification is played on same Bluetooth Device, the dampening goes for that time and the beat is played at full volume.
Other Music isn't dampened but played at full volume.
I have no idea where that effect comes from, windows effects seems to be all disabled.