Dave is the sound guy for the movie Hell Hazers II: The Reckoning.
During a scene in which an actress, portraying a woman named "Kendra", delivers her line, Dave begins to receive a staticky feedback through his headphones, causing distortion to the dialogue.
After Director McG yells "Cut!", Dave informs him that the sound is no good. Although the crew are dismayed by this, with one worker noting that this isn't the first time they've had "costly sound delay", the entire crew agrees to go again.
Dave says thank you in response.
When Brad Redding ends up dead, Sam and Dean decide to investigate the cause. Dean notices something wrong with the sound recorded, and asks Dave to show it to Sam. Both brothers notice the staticky feedback that Dave heard earlier, and Dean assumes it's a ghost – an assumption later proven true.