I think its a little stupid that you flat out cant understand a word from someone using the motor bike helmet or gas mask, you already discouraged players from wearing these with the limited visability and not being able to breath in the gas masks.Speaking of gasmasks i think your stam recovery should only be poor when wearing the gas mask only when you have a filter in it. (gives diversity to the clothes that players are wearing).

Potensial fix for the voice volume could be still having the voice filter on but reduce and also setting anyone wearing these masks to whisper only mode until they take the helmet off.