Recording clean dialogue beside a waterfall
On Lord of the Flies we had a full scene played metres from a waterfall. There is no plug-in for that. There was no single trick either. There was a stack of decisions, made in a particular order, and one of them made post's day.
Every producer I have worked with has, at some point, said a version of the same sentence: we will fix it in post. For most problems that is fair enough. Post is extraordinary now. But a waterfall is one of the specific cases where it is not true, and it is worth understanding why, because the reason dictates everything you do on the day.
Why a waterfall cannot be fixed later
Most noise you can remove is narrow or repetitive. A generator hums at a frequency. Air conditioning sits in a band. A fridge cycles. Modern noise reduction is very good at finding something with a shape and subtracting it while leaving the voice intact.
Falling water has no shape. It is broadband, effectively random, and it sits directly on top of the frequency range where speech intelligibility lives. It is not sitting next to the dialogue, it is sitting inside it. When you try to subtract it, you subtract the consonants with it, and the actor starts to sound like they are talking through a pillow underwater.
So the noise is not the enemy. Trying to remove the noise is the enemy. The job on the day is not to eliminate the waterfall. It is to record a dialogue track where the voice is far enough above the water that the mix has somewhere to go, and to hand post everything they need to rebuild the environment on their own terms rather than fight yours.
Decision one: the boom, as tight as the frame allows
Nothing beats proximity. The inverse square law is the only genuinely free improvement available on a location, and it is worth more than any piece of equipment in the bag. Halving the distance between the capsule and the actor's mouth gains you roughly six decibels on the voice, while the waterfall, which is effectively an infinitely large source spread across the whole environment, barely moves at all.
That means the entire negotiation is with the camera department and the director, not with the gear. How tight is the frame. Can we take a slightly longer lens and buy fifty centimetres of boom room. Is there a shot order that lets us get in close on the coverage even if the wide is a write-off.
On this scene Adyt Santoso was on boom, and a great deal of what made it work was simply him being braver about the frame line than a less experienced operator would have been. That is not a technical decision. That is trust built over four months.
For producers
If you know a scene is beside water, wind or traffic, the single most valuable thing you can give the sound department is not equipment budget. It is thirty seconds of the director's attention at the tech recce, and a shot order that puts the tight coverage before the light goes.
Decision two: radio mics, rigged and re-rigged
Radio mics on a boy wearing almost nothing, in a rainforest, is its own problem. On Lord of the Flies the costumes progressively degrade across the series, which is exactly right for the story and exactly wrong for concealment. Every week there was less fabric to hide a capsule in, and more skin, sweat and movement to contend with.
DPA capsules did the work, rigged and re-rigged as the costumes shed. There is no clever answer here, only attention. You reposition, you re-tape, you check after every costume note, and you accept that a rig which worked yesterday will not work today. Utilities on that unit was Reza Feryanto, and the honest truth is that the quality of a lav track on a shoot like this is decided almost entirely by how many times somebody was willing to go back in and redo a rig that was nearly good enough.
Beside a waterfall the lav earns its keep in a different way from usual. It is not necessarily cleaner than the boom, because it is picking up the same broadband wash. What it gives you is a second perspective with a different ratio, and a fallback when the boom has to pull out of a wide. In the mix, having both is worth far more than having either one be perfect.
Decision three: perspective consistency across takes
The thing that quietly ruins water scenes is not the noise level, it is the noise changing. If the wide take has the falls at one level and the close-up has them at another, every cut in the sequence draws attention to itself, and post ends up doing a great deal of unglamorous work smoothing a floor that should have been consistent to begin with.
So you hold your positions. You note where the boom was. You resist the temptation to creep closer on take four because it sounds better in your headphones, if creeping closer means the take will not cut against the others. Consistency beats quality here, which is not an instinct that comes naturally.
Decision four: the one that made post's day
The part I would do again on every location like this: a proper library of surround wild tracks, captured on location in pristine resolution.
We recorded the falls and the surrounding rainforest as full surround material on a Sennheiser AMBEO VR microphone. Not a token thirty seconds. A genuine library, from multiple positions and distances, at different times of day, with the crew silent.
This changes the conversation in post entirely. Instead of the supervising sound editor trying to remove our waterfall from under the dialogue, they can duck the recorded environment, sit the dialogue in a bed they control, and rebuild the world at whatever level the scene needs. The waterfall in the finished show is not the waterfall that was fighting my dialogue track. It is the waterfall we recorded separately, on purpose, placed where it serves the story.
Post on the show was led by supervising sound editor Niv Adiri, and that library is the reason the sequence works. Wild tracks are the least glamorous line in a sound report and the first thing cut when a schedule tightens. They are also, repeatedly, the thing that saves the scene.
The waterfall is not a problem to be removed. It is a character to be recorded separately and then invited back in.
What I would tell a producer
- Flag water, wind and traffic at the recce, not on the day. Almost every fix available is a scheduling fix, and scheduling fixes are free if made early and expensive if made late.
- Protect wild track time. Twenty minutes of silence on the unit at the end of a day is worth more to the finished show than an extra setup.
- Do not budget for a repair in post. On broadband noise the repair does not exist. Budget for getting it right in the field, which is cheaper.
- Crew, not kit. A boom operator willing to sit on the frame line, and a utility willing to redo a rig for the fourth time, will beat any equipment upgrade you can buy.
You can watch the sequence in my showreel, at around 1:20.
Lord of the Flies (BBC / Netflix), directed by Marc Munden, filmed on location in Langkawi, Malaysia. Boom: Adyt Santoso. Utilities: Reza Feryanto. The series received two 2026 Primetime Emmy nominations for sound.