Time travel on the radio

Live radio talk shows have a problem. What happens if one of the callers says something inappropriate? A naughty word! You can’t let that happen. To get round this, live radio normally includes a time delay to allow any naughtiness to be removed. On radio shows it’s called the dump button. The transmission of the caller’s voice is delayed by around seven seconds and if bad words happen the dump button is pressed and the caller goes silent.

The problem is that you’ve just used up your delay time and are now live. So how do you create another seven seconds’ worth of delay so it’s safe to go back to the callers again? You can’t just sit quietly – that’s dead air and radio listeners don’t like it. Enter computer science. As the host chats, a computer system recognises the natural pauses in their voice, and makes them just that little bit longer. It’s not noticeable to the listener, but after a while you have accumulated enough delay time that the dump button can work again, and it’s back to normal.