Something as simple as the following should work –
In the timeline, you can use a UE4 Curve asset or just draw the fade curve.
Optionally doing a linear-to-dB conversion might result in a nicer fade. The Volume Multiplier value on audio components is a linear volume value currently so it’ll sound better if you either do a non-linear curve or do a linear curve (in dB) and convert to linear volume value before setting it on the audio component. dB-based fades always sound better than linear fades (since volume perception is non-linear, it’ll sound linear if it’s exponential).
So, doing that would look something like this:
Where the timeline curve is just a simple line going from (0.0, 0.0), to (1.0, 1.0).
