Audio gain, fades and crossfades in Video by Zaweba

Three small sound tools do a lot of the everyday work in an edit: gain, which sets how loud a clip starts out; fades, which bring a sound in and out gently; and crossfades, which blend one sound into the next. Video by Zaweba gives each a quick way in and enough shape choices to sound right.

Audio gain

Edit > Audio gain, or the G key, works on the selected sound clips. It can set the gain to a value, change it by an amount, or normalise the peaks. Normalising raises or lowers each clip so its loudest peak lands at a set level, which is a fast way to bring a batch of recordings to a similar starting point.

Gain is best thought of as the starting level of a clip, set before you mix. Get every voice clip into roughly the same range with gain, then use the faders and keyframes for the moment-to-moment changes. If you try to do it all with faders, a whisper recorded quietly will fight you the whole way.

Bear in mind that peak normalising doesn't make clips sound equally loud. A sharp laugh can set the peak while the speech around it is quiet. It's a good first step, not a finishing one.

Fades

Every sound clip has a small square at its corner. Drag it inwards and you get a fade: in at the start, out at the end. A short fade, a few frames long, removes the click you sometimes hear when a sound starts or stops abruptly. A long one lets music swell in or drift away.

There are five fade shapes. Linear changes level evenly. S-curve starts and ends gently with the change in the middle. Equal power keeps the perceived loudness steadier. Exponential and logarithmic bend the change towards one end or the other.

Your ears judge loudness on a curve, so a linear fade out can seem to drop away suddenly at the end. If a fade sounds wrong, try a different shape before changing its length.

Crossfades

Where two sound clips meet, a crossfade blends one into the other. There are three types. Constant power keeps the overall loudness steady through the middle and suits most joins, especially between two pieces of music or two ambient beds. Constant gain is a simple straight blend, which can dip slightly in the middle but works well between similar sounds such as two takes of the same room tone. Exponential leans the blend to one side.

The quickest way to add crossfades to many joins is the default transition shortcut for sound, Shift+D, on the selected edits.

Fade everything a little

Fade everything, even if only by a few frames. Hard starts and stops on sound are one of the most common giveaways of a rushed edit.

Match the fade to the content. A music bed that's ending deserves a long, smooth fade; a line of dialogue only needs a tiny one at each end.

And set gain before you start mixing. In Video by Zaweba, a little care with G at the start of the sound pass makes everything after it easier.