I want to fade a noise (beeping noise, like a heart monitor) in and out during different scenes/moments in a movie without the audience noticing the change. It should appear as being there all the time, but the audience should notice the change, when it gets in a new time. I hope that is understandable :D

I thought of more or less crossfading it to a white/brown noise or so, but that did not work out as expected.


5 Answers 5


The first thing is, don't make it totally gone at any point. Listen to the audio of medical dramas like Grey's Anatomy; the sound never really leaves the soundtrack completely. Fade it down and up, but not completely out.

Second, use viewpoint changes in the camera editing to adjust the level of the sound; take the opportunities when the camera moves further away from the sound source to reduce the sound level in a more natural way, then it's up to you whether to being the level back up when the viewpoint returns to put the monitor back in frame. You'll to pay attention to your stereo/surround image as well to make it believable; with the sound in center field while the camera has the monitor in view, when the camera moves right the sound moves left and v.v.

Third, you can usually get away with fading "background" sounds down slightly as a character starts speaking (or is just about to); we've become accustomed enough to the compressed sound of modern mastered audio that this doesn't sound jarring. Some of this really is from compression inherent in mastering and in broadcast transmission, but you can use a touch of it yourself in media formats like movies that are typically less compressed.

When the audience needs to remember the sound is there, or pay attention to a change in that sound, you simply bring it back up to prominence in the mix.


Keith gave you some great tips already. In particular, the idea of change is a key psychoacoustic cue to pay attention to something. The more regular and static a particular sound is, and the longer it remains that way, the more likely we are to ignore it. Get it to the point where we are ignoring it, and any little change draws your attention back to it. This requires time though, and sometimes we don't have the requisite amount to pull this off.

Something else you can do is utilize another masking sound to obscure the entrance and exit of the sound. So, here I disagree with Keith. There are times when you can take it out completely, but it's very context dependent. In the very least, you can use this masking sound(s) to hide a volume change that moves this sound between background and foreground. That will help counteract the problem of not having enough time for the psychoacoustic effect to take hold.


Try adding a Low-Pass filter to the beeping sound and automating it. The more high frequency is cut out, it will sound as if it's fading out.

  • The effect of cutting out the highs from a sound makes it sound like it's coming through a wall, so this may be especially effective if the camera moves into a different room than the sound source.
    – Kevin
    Jan 29, 2014 at 22:02

I think these guys have provided some great answers, but one answer I'm not seeing is to morph the sound. The idea being, the beeping monitor sound changes to something else over a period of time. Slowly morph the sound using filters, distortion, oscillators or other sound fx.

You could also morph the sound into another sound, and since a heartbeat is rather rhythmic, blending/cross-fading it into the beat of the song, or a percussion track could go a long way. This way you can make the sound completely disappear without it being noticed as "gone" because something is replacing it.


Something that realy helps is a insane amount of roomtone/atmo. A Lot of Professional Series have huge amount of those-> fadeing Sounds will be masked by atmo! Also as stated before use Loud Sounds and Camera changes to start or stop longer Sounds!

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