How to Create an Underwater Audio Muffle Effect in Adobe Premiere Pro CC (2018)

Audio is just as important as visuals when it comes to selling an effect. Think about how different the world sounds when you are underwater. Everything becomes muffled, bass-heavy, and distant. High-pitched sounds like voices and birds disappear almost completely. If your video has an underwater scene but the audio still sounds like it was recorded on land, the illusion breaks immediately.

The good news is this effect is incredibly easy to create in Premiere Pro. All you need is the Low Pass filter. It cuts off the higher frequencies and leaves only the low, bassy sounds that you actually hear when submerged. Let’s walk through it.

How to Create an Underwater Audio Effect in Premiere Pro

1. Find the audio clip you want to apply the effect to in your timeline. This could be music, dialogue, ambient sound, or all of the above.
2. If you only want the effect on a portion of the audio, use the Razor Tool (C) to cut the clip at the points where the underwater section begins and ends. This way the effect only applies to that segment.
3. Go to the Effects panel and search for Low Pass (under Audio Effects > Filter and EQ).
4. Drag the Low Pass effect onto your audio clip.
5. In Effect Controls, find the Low Pass filter. Set the Cutoff frequency to about 450 Hz. This removes everything above 450 Hz, which eliminates the crispy high end and leaves only the deep, muffled bass. That is exactly what sound underwater sounds like.
6. Play it back and adjust the cutoff to taste. Lower values (200-300 Hz) sound deeper and more extreme. Higher values (600-800 Hz) sound less dramatic.

Animating the Transition

If you want the audio to gradually transition from normal to underwater (like a character diving in), you can animate the cutoff with keyframes.

1. Click the stopwatch next to the Cutoff property.
2. Set a keyframe at the start of the transition with the cutoff at a high value (around 8000 Hz or above, which sounds basically normal).
3. Move forward a second or two and set a second keyframe with the cutoff at 450 Hz. The audio will smoothly transition from clear to muffled.
4. To bring it back, reverse the process. Start at 450 Hz and keyframe back up to 8000+ Hz.

Tips

• Pair with reverb. Adding a slight reverb on top of the Low Pass filter makes the underwater sound even more convincing. Water creates a lot of natural echo.
• Lower the volume slightly. Sound is quieter underwater, so dropping the clip volume by a few dB adds to the realism.
• Apply it to all audio tracks. If you have music, dialogue, and sound effects playing at the same time, make sure the Low Pass filter is on all of them. If only one track sounds muffled and the others are clear, it will sound wrong.
• Use it for other scenarios too. The Low Pass filter is not just for underwater scenes. It works for muffled sounds through walls, phone calls, dream sequences, and any time you want audio to feel distant or filtered.

That’s all there is to it. One effect, one slider, and your audio instantly sounds like it is underwater. Simple but incredibly effective.