Low cut for movie audio

Discussion in 'Mastering' started by Dr_Willie_OBGYN, Jun 26, 2016.

  1. Dr_Willie_OBGYN

    Dr_Willie_OBGYN Active Member

    What is the low frequency cut off point that you're supposed to use to cut out low end that people can't hear? i know there's low frequencies below a certain point that only cause distortion.
     
  2. Boswell

    Boswell Moderator Distinguished Member

    There are several different questions here.

    Firstly, audio recording can be required to go down quite low, sometimes below the conventional lower point of hearing. This point varies from one individual to the next, but is often taken as being 20Hz. Note that it is not a sharp cut-off in the hearing, but more a point where the sensation moves from being mainly heard to being mainly felt. Whenever I have used spaced omni microphones to make recordings of cathedral organs, at set-up time I ask the organist to walk slowly down the pedalboard repeatedly while I look at the microphone waveforms as an X-Y display to check for phase irregularities in the extreme low end. Some churches have very odd responses around there, and it's a matter of moving the microphones around until an acceptable place is found. When I come to replay these tests at mixdown, I am aware of the movement of sensation from hearing to feel, and by the time it gets to the lowest note at about 16Hz on a 32ft pipe, it is almost entirely felt (except for the rattling of everything that's loose in the studio). My sub is coughing around there anway.

    Secondly, there is no inherent distortion in the low end of the hearing range at normal volume levels. Any distortion you hear in your recording comes either from not knowing how to use your equipment or trying to use gear that's not up to the job.

    Having dealt with those two points, the rest is largely down to how you should shape the frequencies of individual tracks in a mix. In studio recordings, it's conventional to cut the low end of vocals at 80Hz or so (higher for female singers) to minimise breath noise and other vocal artifacts and make the vocal track "sit" better with other tracks in the mix. Live recording work can often need more low cutting to keep out bleed from bass instruments, HVAC, stage floor boom and other unwanted LF.
     
    Brien Holcombe and kmetal like this.
  3. dvdhawk

    dvdhawk Well-Known Member

    If you're asking because you have a song being considered for use in a movie, just produce the best song you can and let the movie people worry about optimizing it.

    If you're producing a movie, and trying to keep everyone's woofers from 'farting out', I'd say use the same philosophy. Produce it the same as you would any other project. A tinny built-in speaker won't even try to do lows, and a person with a serious theater sound system will take all the lows you'd typically mix/master with your studio monitors. Hopefully the audio recording was used because it's overall vibe matches the visual (light and airy, warm and welcoming, down and dirty, dark and twisted).
     
    Brien Holcombe likes this.
  4. DonnyThompson

    DonnyThompson Distinguished Member

    If you are mixing audio for a commercial movie, then the film studio should tell you what format they want you to deliver in - it might be standard stereo, or it might be 5.1/7.1 - at which point you should mix and monitor in the appropriate format.

    If you are asked to simply provide a stereo audio file - unless they give you specifics as to HPF, or other processing or frequency adjustments - mix it as you would any other project that you would do, and let the sound editors handle the file on their end.

    For example, if a movie decides to use something like The Stones' Sympathy For The Devil as an overlay for a scene, they're not going to expect the recording studio to open up the original master and remix it; they'll just use the original commercial version, and then the sound editors on the film will make any adjustments necessary.
     
    Brien Holcombe likes this.

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