The one audio tool you can’t start your film career without?

Okay you need a full tool bag to get started in film making but one item you should use on your first film, last film and all the films in between is a 2 pop. If you don’t know what a 2 pop is let’s be honest, you’re not a film maker.

Editors use a MARKER or 2-pop at the start of every film. A 1 kHz tone that is one frame long and placed 2 seconds before the start of picture (whether that picture is black grey fading in or test pattern). It is a simple and effective method of ensuring synchronization between sound and picture in a video or film.

https://en.wikipedia.org/wiki/2-pop

Typically a 2-pop is placed at the end of a visual countdown. As the countdown hits 2 seconds before picture a number 2 is shown (usually in white as opposed to the black background white numbers of most countdowns) and the remainder of the 2 seconds prior to the program is black. This provides a unique point of reference where the frame-long image and frame-long sound should align, similar to the way a film clapperboard is used to generate a synchronization point.

A 2-pop is useful whenever picture and sound are handled separately. And in the real world of film making … this is almost always the case.