Radio sound effects

Thin whistling notes sliding past each other as the dial travels. The card most scenes want, because it is the one radio sound an audience recognises with no picture at all.

Small dry clicks with almost no tail on them, spaced unevenly the way a hand actually turns a knob. Use it when the shot is on the hand rather than on whatever the set is receiving.

The click, the short rough burst and the beep that bracket a transmission. Put one at each end of a line and dialogue recorded anywhere starts sounding like it came down a channel.

A soft thump through a paper cone and the steady hum that settles behind it. Older equipment takes a moment to come alive, and that moment is what dates the set for the audience.

Short and long tones at one pitch with clean silences between them. It reads as a signal carrying information, which is why it works over a map, a console or a title card.

A tone rising and sinking under a slow warble with the high edge gone. Nothing here says how far away the transmitter is, and yet everybody hears that it is a long way off.