To my knowledge, ever since the launch of WAW, there has been a major problem involving sound quality of things like voices when your output device's sample rate is set to anything above 16-bit/44.1KHz. This is a problem exclusive to WAW, and does not happen on games prior to WAW, such as COD2, and COD4.
A good video demonstrating said problem can be seen here.
My hypothesis as to why this happens, Is that WAW handles sound a bit differently in the way of which you can't manually set the sound quality like the games before. Instead, WAW attempts to read the windows settings to automatically configure the sound quality. Unfortunately, the game doesn't seem to know what to do when the audio device is set to above 44.1KHz, so it chooses to default to the lowest possible quality.
The only method (published online) that's known to fix this, is to set the sound quality in windows to 16-bit/44.1KHz. Okay, Pretty easy, right?
Unfortunately, with certain sound devices, it won't even allow you to change the setting to said value. and even if you were able to change it, it still requires you to revert this setting back to a higher setting in windows when you don't want to play WAW anymore. Pretty inconvenient, if you ask me.
I'd like to bring this up to the team at Plutonium, because being able to look into the problem and potentially fix it, would improve the experience for so many other players looking to play. Even if a fix isn't possible, I hope bringing light to the problem can allow the community to potentially find a workaround.