Cockpit Volume control seems to mute engine noises below a certain threshold

[Eddie]

I usually fly on VATSIM and thusly have to keep the cockpit volume turned quite low down in order to properly hear ATC. I can typically hear the engines spooling up and down during taxi and takeoff, but can't hear them at all in other stages of the flight. To test this, I turned the air conditioning volume all the way down and continously throttled the engines up and down during approach, but couldn't hear anything from the engines at all until I turned the cockpit volume up past the halfway mark, at which point the engines became completely audible again. It seems that the slider is selectively cutting the engine noise out altogether below a certain threshold, and for some of us for various reasons, turning the volume up is not a viable solution all the time.