Hello soundies.. I was wondering if anyone knew an example of when a film has used a single tone frequency (or if they ever have) that sits below the mix and creates an almost subliminal 'uneasy feeling that could be perceived as tension. A bit of a weird question, but why not ey///


10 Answers 10


Good question; i know this occurs to a lot of sound designers at one time or another. A lot of examples of cinematic tinnitus are around (Children of Men, Saving Private Ryan, Noise, etc.). In those films it's more of a psychological diegesis than a non diegetic effect, though (which is what i think you're talking about).

A couple of potential problems for this approach are:

  • Playback system frequency response; if you're trying to use a very high (or low) tone to induce discomfort, it may not even come through on some playback systems. Not to mention the fact that an older person might not even hear a higher frequency tone, while it won't be subtle at all for a teenager.

  • Habituation; Constant sounds that don't change are pushed to the back of our psychoacoustic perception. I can't say whether or not this will negate any subliminal effects, though. An interesting idea that this brings up is that an audience member may notice when such a tone stops, while not being aware of what exactly has changed. I think raising a question (however small) for the audience can be very effective in the right place.

IMHO, using a single tone in an attempt to subliminally affect the audience is a bit of a clumsy technique by itself. The idea behind it can be a good starting point for creating effects more specific to your film's needs, though. Like the tinnitus/ear ringing thing, or low thunder/synth rumbles.


Gaspar Noe's Irreversible does this in the first 30 minutes of the film. I've heard that it was so effective that when the film was screening at festivals around the world, there were occasions of people vomiting, fainting and all other kinds of hysteria happening. Watch at your own risk though, it's a very intense movie and not for the faint of heart.


As @Roger mentions, subtly removing tones / ambiences / that have been established without the audience even noticing is something to experiment with -- it can have the same effect subconsciously, and personally I prefer that approach because it's harder for anyone to say "yes I can hear your 'tension' sfx, thankyou very much", which can be a bit of a boom-in-shot.


In the Black Swan I noticed lo frequency tones used to anticipate tension. I noticed them because I was paying a lot of attention to the sound track. They are quite evident for some one "analyzing" the sound track but I don't think the average viewer would consciously understand their use or their presence..

Very low frequencies which are not perceptible by the ear can be felt through the body, but as Roger explains above, a play back system that can reproduce such frequencies is an issue. Cinema play back systems have always had a problem with the reproduction of low frequencies.

This link is not related with film but is about low frequency noise and its effect on people.



eraserhead has a horrible hum thru it that created a ton of tension.

  • 2
    I think it's mostly the sound of machinery hum, which helps set the "industrial wasteland" tone very nicely. I believe the bulk of that background "ambience" is made from tapes that Lynch found in a dumpster on the film lot where they were shooting it. Old stock audio footage. Something like that. He talks about it on the special edition DVD. Dec 5, 2011 at 22:41

not focused exclusively on frequencies, but you should check out this thread on creating tension. a lot of great ideas and information contained in it.

Tension sounds like…


More to do with uneasy harmony but "How to Disappear Completely" by Radiohead has a high-pitched tone that carries for the first 1.5 minutes of the song.


Silence: The most uneasy frequency of all. :)

Badalamenti uses it masterfully in the Lynch films.


thought of clusters?


thank you all for your replies,, really helpful..

@dbp - I think that the radiohead method could really work if used as a subtle, low in the mix sound that when taken out abruptly reinforces/ elevates the viewers emotion.

@ruben - I have seen the film but obviously my speakers didnt pick that up.. still thats a dark film.

@Eric baca - interesting stuff, thanks for the link - i still need to see Black Swan, ill check it out.

thanks again all.. i will put up a link on the finished product..

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.