I just did test, and when i choose 24bit ,44100 Hz sound sampling i dont loose any sound in multi or single player.Default was on 48000 Hz.
;)


Sound properties-Speakers-properties-advanced other two tickers unchecked

Well, I've tried several different settings, but after tweaking my info box, I was able to get errors reported in the chat box. And as soon as the sound started crapping out I get this error;

1395162 ERROR [SOUND] Sample
$bob/speech/gb/Actor1/Feet.wav not found

It only happens when flying RED team. Which makes sense for me since its a gb (Great Britain) sound file not found. It never happens if I fly blue and stay blue, but once it goes out (by switching to red) it stays out until i restart game, sometimes I have to restart computer.

But I have heard different from others, that it happens on blue team to them...

Asus P8P67 Deluxe Mother Board
Intel 2600k 3.4ghz quad core Sandy Bridge
8gig RAM DDR3 COSAIR @ 1600mhz
On board HD Audio Realtek
Asus 580GTX 1.5 gig RAM DDR5

Yes indeed the drivers I called "custom" were precisely these ones, which I knew from before IL2 COD since they fixed problems associated with Audigy cards with other games (but I had shelved the card and was using the headset as my main sound device anyway, I only took it out again to test the bug).

I might give a go at testing the problem again if I can figure out how to log errors in the chat box as you did Srinidhalaya. I am almost 100% positive that I experienced the problem on the blue side too, but I shall check that too again.

Where to make this adjustment?
 

My in game audio menu only has volume adjustments showing and when I go to the conf file, I don't see how to make adjustment.