Currently there is no voice level alterations, I believe it can be altered within your Voice settings to the level of your mic output. Once within the given VOIP range and the default key "n" pressed you will speak at an constant level. (You can also have voice activation i believe but i personally havent tested that out)
There is a fix for this in next update! Voice proximity and 3D audio, with relevant drop off! We will continue to assess this going forward but voice system is now 5000x much better.