Hi everyone, I've been gone for a while, but i'm back now. I have three ambient_generics playing at volume 10 with "start silent", "play everywhere" and "is not looped" checked. Two are triggered by buttons with the "onpressed > entityname > playsound" outputs and the third is triggered by a trigger_once with the "ontrigger > entityname > playsound" outputs. These three sounds play in the Hammer sound browser but don't play in-game.

These sounds are:

NPC_dog.Ravendoor_Creak
MetalGrate.StepRight
JumpLand.Metalgrate

At least for the MetalGrate.StepRight(and likely also the other ones judging from their name) I know it should produce a very low volume when set to 10 despite sounding loud in Hammer. Have you tried triggering them in a situation where the rest of the game is quiet?

I just tested and it works fine for me with similar settings so I wouldn't know why it doesn't work for you unless the activator entities are set up wrongly. Try typing this command ingame to fire the entity manually just to be sure: "ent_fire thesoundentity PlaySound"