I played Project Zomboid few days ago and i was suprised how dangerous are the zombies with acute hearing. This feature not just missing from the CDDA, but our zombies are so ignorant to sounds, this severly hampering their dangerousness in the game.
Every time i make a loud noise they ignore it or - seemingly - aware of it just for few turns only. In an older release i shot zombies with gun in a FEMA camp and the soldiers in the nearly tent made some noises but never came out.
Now i hit dozens of zombies with a loud truck in the Research Facility, there are zombie cries, sound of crashes and shreading car parts, but the other zombies not far away just don’t give a damn. They act perfectly fine when they see me, some zombies even follows other zombies to me (i see the exclamation mark on the leading ones), but they are almost totally oblivious to non-continuous(?) loud noises.
I think it is a big problem. Hearing range should be larger also zombies should be much more persistent to investigate noises.
Now, i think about it, i was never discovered by zombies by hearing when i looted a house, not even when i made noises like climbing on furnitures or put away items. The only exceptions when i purposely smashed fridges or walls. This alone makes the looting much more easier.
Also, i think they are too passive, i can sleep in a house while zombies outside. They come in if they can smell me, but they never wandering in accidently. At least this was my experience with them in the past, i didn’t do it in the recent past.
Edit: zombie security guards thump to lure other zombies to the player, also useless. 
