Oh yes, they definitely know the feeding tub, lol. I'm not sure about listening, but they all certainly respond to my voice. Cleo responds to my voice to the point that if she gets startled while eating, talking to her will have her immediately start moving the prey down her throat again. I've been able to reproduce this so I know it is not a fluke.
They definitely are smarter and more responsive to us and their environment in general than I believe science currently gives them credit for, though I try to avoid anthropomorphism. Reptiles in general and snakes in particular are not stupid. They have finely honed snake skills, and at the least talking to them does no harm.