need help with ATC

When I fly 4-engine jets (b747, A340, etc). I cant hear ATC but i can see the text. after i shut 1 or more engines down I start hearing ATC. Is there a way to fix this? 

Flight Simulator and other chat
https://forums.simviation.com/phpBB3/
https://forums.simviation.com/phpBB3/viewtopic.php?f=30&t=87333
Finally, you may be asking yourself what use it is turning the audio on for Nav1, Nav2 and the ADF? All you hear is this annoying morse code!