Ever crewed an armored vehicle personally? I served in a mechanized infantry unit for four years. We used M2 series Bradleys, including the M2, M2A1, M2A2, and M2A2ODS variants. I personally spent time in my unit as a Bradley driver. Every single variant, as well as every other armored vehicle that I encountered in the U.S. arsenal had plugs for this kickass helmet called the CVC helmet. CVC stands for Combat Vehicle Crewmember's helmet. Basically, it is a helmet with big *** headphones built in that drastically reduce noise, while providing amplified volume for communications inside the vehicle.
(Source)
Of particular note, I will quote from the linked source:
SOUND-ATTENUATING EARCUPS: The rotatable earcups are designed for a secure fit and optimum sound attenuation. The earcups can be adjusted vertically via the adjustment straps on the CVC liner. A tension spring adjusts pressure of the earcups to the crewmember's head. A raised ring on each padded, non-hardening, polyurethane earseal further enhances the fit and sound attenuation with minimal pressure to the head.
OPTIONAL ACTIVE HEARING PROTECTION (AHP): An optional Active Hearing Protection (AHP) talk through system is available for use with the DH-132S/DH-132AS. This battery-operated system allows the crewmember to have noise attenuation plus the ability to hear conversations clearly; it also helps protect the crewmember's hearing by suppressing noise levels above 85 decibels. The AHP system consists of an outside communications module on the left earcup (as worn) and a rotary switch on the right earcup. Alternatively, the AHP feature is available from Gentex in a self sustained plug-in module which is worn on the body with a clothing clip.
ACTIVE NOISE REDUCTION (ANR): ANR is available as an option for increased attenuation at the lower frequencies 31.5 through 1000 hertz.
ELECTRET MICROPHONE: The MK-1697/G headset-microphone can be modified by installing a transformer and diode capacitor network in the left earcup to permit the use of a high performance electret microphone with superior noise canceling characteristics and improved EMI performance.
In conclusion, I see no realism argument against this idea. The statement about lowered game audio settings affecting survivability in infantry play is without a doubt correct, however.