You are walking down a street with a few tall buildings either side, you hear a helicopter approaching.

Which direction in the sky do you look?

Even though I can quickly figure out where the sounds are going to reflect against the buildings and pinpoint the helicopter, my ears automatically direct me to the wrong direction.

My question then is, where or how would you pan this helicopter sound in your film?

6 Answers 6


Whatever is less distracting.

If the picture clearly shows the helicopter coming from the right, but I pan it to the left because of the reflections, the listeners are going to think it's really odd and will definitely pull them out of the film. In that scenario, I would pan it in relation to where the chopper is.

If you can't see the chopper, I would probably keep it centre. A helicopter sound with a decent amount of reverb is enough to create the illusion, panning would just be distracting.



Do you mean that your ears direct you to the wrong location in real life? That happens all the time because of obstruction and reflections.

The better person to ask is the person directing the film. What's trying to be conveyed in the scene? Sound does not have to conform to real-life in all settings. The important thing is how it helps focus the viewer through the story. Will it be distracting if it's panned to the wrong location, or will it support and blend with what's going on at that given moment?

  • Hi Shaun, I have a fair understanding of acoustics, it's a hypothetical question directed at sound people, no right or wrong answer, just want to know what you would do knowing that from the image in front of you if you would fake it or make it sound like reality. That is, before the director gets in there and ruins your ideas!
    – ofa
    Oct 29, 2011 at 16:47
  • 2
    @ofa - it's a judgement that i would make in the context of the scene/story. in addition ot the panning ideas, i could very well decide not to use it at all. anything you add to, or leave out of, a soundtrack affects the presentation of the story. my personal decision would be based on too many other factors to provide a definitive answer here Oct 29, 2011 at 17:10

I agree with Fred here. I think cinema sound has a set of conventions which don't necessarily reflect reality. When you break those conventions for no other reason than to reflect reality, it tends to stick out as a "mistake" to an average viewer. Film is a collaborative medium though, so a realistic sound treatment can work very well if it's supported by another area, such as cinematography, editing or acting.

I was actually thinking about this exact phenomenon last night, walking home. Fireworks to the west sounded exactly like they were coming from the east whenever i was between buildings. It's a cool psychoacoustic effect.


In a standard film scenario I think I would fall on the side of the cinematic approach, where panning corresponds to the direction of the helicopter as opposed to what would happen in reality. I guess it's a similar argument to the way distant explosions/lightning strikes are traditionally treated in films; you hear them as the event is seen rather than after what would be a small delay in real life. This is one of those crazy conventions that Fred and Roger refer to.

Incidentally I was reading some comments on a Battlefield 3 trailer earlier and everyone was complaining about hearing the gunshot at the wrong time i.e. it wasn't realistic. I think people were more intent on pointing out the fact that they knew the gunshot would come later rather than trying to improve gameplay - I'm sure the sound designers at DICE are well aware of the physics but chose this approach because in such a fast paced game it would be utter chaos (not saying that you have the same reasoning for bringing this up ofa :D )

I also agree with Shaun however that the sound treatment is relative to whatever is happening in the story at that particular moment and/or the style of cinematography. Maybe it would benefit the scene to intentionally make it disorientating and flip all the panning round (I quite like the idea of doing that for something....dibs!)

So anyways, back to the original scenario, maybe a good way to illustrate the building reflections would be to pan the helicopter in the "correct" direction, and send the same signal to a bus panned in the opposite direction with 100% wet slapback reverb of some kind? So you get the dry signal coming from the helicopter on the right and a slightly delayed reflection bouncing off the building on the left sort of thing.


I often fall back on the question, "Does the object (not the sound, the cinematic element) in question sit in the foreground, midground or background of the scene?" Is it shooting at me (foreground), does it represent some amount of danger (midground), is it ambient in nature (background)? Does this change during the course of the scene? etc.

On a side note, a heli is a beautifully complex sound that is affected greatly by wind, obstruction/occlusion, and acceleration direction (toward, or away). There are at least 2 distinct elements (engine and blade) and they respond differently from each other (the rate of the thwop thwop remains pretty constant, while the engine changes pitch and intensity with acceleration and direction changes. Next time one passes by, give it a listen.


It happens a lot in film, panning is less than psycholigical, more than real, when I'm paying attention to things.

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