If you’ve ever gone under the water at a pool party while music is playing, you’ll undoubtedly notice that there’s a clear change in the sound of the music. Maybe more commonly is you’ve simply heard this change in tone when seeing the representation of music heard under the water in a movie or TV show. It’s easy to replicate this effect in your own mix, so let’s talk the underwater EQ settings you can drop on any track in your mix to get this effect.
Underwater EQ Settings
The trademark of the underwater EQ sound is a very aggressive top end low pass filter.
A low pass filter removes everything ABOVE a certain point, allowing the lower frequencies to pass through unabated:
As I covered in my comparison of high and low frequencies, high frequencies get reflected or absorbed by walls and obstacles more easily:
Conversely, low frequencies move more slowly but are able to travel farther distances, even permeating some walls and obstacles.
This is why when a car drives by you with its windows up or passes by your home while blasting music, all you can hear is the bass thumping.
This is the same principle at play when it comes to hearing music under water; higher frequencies are effectively filtered out because the surface of the water creates an impenetrable wall for higher frequencies.
With that in mind, drop an EQ at the end of the chain for whatever you want to apply the underwater EQ effect to.
On the low end, apply a high pass filter at 20Hz. While theoretically the lowest frequencies would be the last thing you’d lose, 20Hz is as low as the human ear can perceive, hence the optional filter to remove what we can’t hear anyway to add mixing headroom.
The important filter doing all the heavy lifting in the underwater EQ to simulate that effect is the low pass filter at 300Hz.
Note that 300Hz is a suggested starting point; you may prefer to this a little higher to let more of that mix through. It’s all about what you want that effect to sound like, or what sounds most convincing for that effect.
You can also use this low pass filter point to reflect the literal depth under the water you want to simulate. If you want to go deeper, drop that filter lower down to 200Hz. If you want to feel like you’re closer to the surface, raise it up to 400-500Hz.
You can also automate this filter higher to simulate the effect of swimming to the surface and coming out of that water. This makes for a very satisfying use of mixing automation for an intro, tail end of a bridge or fill, etc.
Going from this very filtered sound to experiencing the full spectrum of the audio, particular when we’re using this underwater EQ effect on the master bus, is very refreshing to the ear.
Bonus Tip – Add Chorus
While the underwater EQ does that heavy lifting for that effect, I like to add a little chorus after the EQ.
Arturia’s Chorus Dimension-D adds a little warble which lends a bit more of that underwater feel to the audio:
My favorite combination is depressing the buttons for both mode 3 and 4.
You don’t need this specific plugin; any chorus can add some of that warble-like, evolving sound which can give that audio the feeling of moving around and through the water molecules.
Try a “Rate” setting somewhere on the faster end, 4Hz is a good starting point, and turn it up for more noticeable movement or down for a more subtle feel.
A 50/50 Dry/Wet mix is also a good starting place to get the dry and chorus doubles to be on equal footing to really hear the effect by way of that dissonance.
