Sound quality and volume change in X-Plane 12 when launching VoiceAttack

[voiceclik]

Hi, I haven't found yet the way to maintain the same quality and volume of sound while using X-Plane 12 once launched VoiceAttack: volume gets lower and quality worse. If I close VoiceAttack situation returns normal.
Tried with and without earphones.
Any hints or suggestions more then wellcome.
Thx in advance for supporting, appreciated

[Pfeil]

Are you using a Bluetooth headset?

If you search the Windows Start menu for "Windows Speech Recognition", start that application, dismiss the dialog that comes up about deprecation (this does not directly affect VoiceAttack, it only applies to the application you just started), then make sure the orb on the left is blue (if it's any other color, click it, so "Listening" is shown), does the same issue occur?