That's the image, and the sound, I can't shake after watching HBO's Hear and Now, the evocative, emotional, breathtakingly personal documentary by Irene Taylor Brodsky.

The documentary, premiering tonight at 8, is Brodsky's up-close-and-super-personal study of her own parents, Paul and Sally Taylor, both of whom have been deaf since birth. At age 65, they decided to risk the same operation and get fitted with cochlear implants, giving them the chance to hear, for the first time, the world and people around them.

Hear and Now spends more than a year with them. Home movies let us know how they met and married as young adults and spent their lives together, raising a hearing daughter and outfitting their lives with inventions generated by Paul, a professor. Brodsky films her parents taking a solitary winter walk, shortly before undergoing the operation.

Overhead, geese fly by and make that unmistakable honking sound. Well, unmistakable to us -- inaudible to them. Brodsky achieves exactly what she set out to do there: to make us notice the sounds we take for granted, and to imagine what life would be like without them.

And then, on the flip side to imagine what it would be like to hear those sounds, and others, for the first time. The daughter and her camera are in the room when her parents have their implants turned on for the first time, and hones in on their faces as they absorb their firs auditory experiences. He hears an electric tone, and his eyes widen with amazement. She says "Hello," to herself, and can't believe what she's hearing. Or that she's hearing.

"What does it sound like?" the doctor asks Paul, the professor.

"That's a tough question," Paul replies deliberately (subtitles help us understand what they're saying when their speech patterns aren't clear). "It's like, how do you describe what green looks like?"

Because this is real life, and because Brodsky is an unflinching filmmaker, Hear and Now has its sad moments as well as its happy ones -- plenty of them, in fact. But late in the film, when the two of them go out on another winter walk and discuss whether the geese are communicating by honking, well, it's a moment I'll never forget.

And I'm guessing it's a moment they, and their daughter, will never forget, either.