Hero's door-opener doesn't need pipes and a bottle and a bucket: the expanding air could have moved the rope by filling a rubber bladder. Except the Greeks didn't have rubber. (Therefore if they had had rubber, we'd have no steam engines?) The noise-maker could similarly have sent air through its organ directly, I'm not sure what's wrong with that, it doesn't seem to use hydraulics to increase the rate of flow, maybe some evening-out occurs that improves the sound?