The reason the audio may not work could be due to the multiple audio channels. It often depends on what the audio is set to versus what the source is. For instance, if the audio on the TV is set to "stereo", but the source is 5.1, you'll not hear any of the center track on the TV, only faint surrounding "room" noises from the set, or things such as cars going by and the like. Since the center track usually is all the voice content (think that the subject is right in front of you, "front and center"), I found that to be a big problem with a TV where my father-in-law was staying at a rehab. Most of the TV content was 5.1 but the TV was only playing the right and left channels. There were entire TV shows he couldn't watch because he couldn't hear them talking. Then out of the blue commercials would come blasting in at ear-deafening levels. Or you'd hear music but no voice.