Since the last major update, the sound of allied engines has been way overtuned. I use Steelseries Sonar, which boosts the bass, and with it, you can actually see (hear) how absurd it is.
Allied tanks have around eight times more bass than your enemies. In order to get the bass equalised, I needed to put the bass in Sonar to +8 dB (out of 8). At that level, an allied IS 2 moving literally disables my headset’s subwoofer for safety reasons. And note that dB is not linear, meaning that while 0 to +8 might be an 8-fold increase, the perceived sound difference is much greater.
I don`t know what Gajin did, but they fucked up tremendously and have ignored all reports of this issue.
Right now, it is impossible to hear an enemy 20 metres from you over the sound of an ally 500 metres away. Making the game considerably worse.