Swear Bleep Detecting Eyebrows

Swear on broadcast television and they’re going to bleep out the audio to protect the sensibilities of the general public. Swear bleeps are fairly standardised at 1kHz, or so [mechatronicsguy] tells us. You learn something new every day.

OK, it’s not as though there’s an ISO document somewhere detailing the exact tone to use when someone says a naughty word on camera, it is far more likely that a 1kHz tone is the most likely frequency to be at hand in a studio. It’s so ubiquitous that even audio engineers with nowhere near perfect pitch can identify it, and one to which an acquaintance of ours swears years of exposure have given his ears a selective notch filter.

Armed with this information, [mechatronicsguy] created a fun project. As a fan of the [electroBOOM] Youtube channel he made a set of LED eyebrows for a picture of his bleep-prone hero, and using a Teensy with its audio and FFT libraries he made them light up whenever a 1kHz tone is detected. It’s not the most amazing of hacks, but if you find yourself in need of a smile on a chilly November morning then maybe it’ll have the same effect on you as it did with us. He’s posted a quick video of the ‘brows in action which we’ve embedded below the break.


If this slightly frivolous project has sparked your interest in the capabilities of the Teensy audio library, we talked about it in a bit more detail a couple of years ago.

17 thoughts on “Swear Bleep Detecting Eyebrows

  1. Though bleeps on reality shows these days are like…

    Hubby: Is your dear mother coming to stay again this coming weekend?
    Wife: Yes after she’s finished visiting her hairdresser. Oh and honey can you take out the bathroom garbage you’ve been slightly lazy about it.
    Hubby: Sure thing bunnikins right after I put these insoles in your shoes.

  2. Hmmm, could make an automatic swear jar for TV shows.
    Hears beep, drops coin into jar.

    Bring it to an art gallery and sit the jar onto a television or tuned to whatever terrible ‘reality show’ is on at the time.

    1. A Discovery channel TV show about fishing for crab in the Bering Sea amusingly used loud boat/mechanical/equipment noises to mask the sailor’s swear words. Their audio engineers must have had quite a workout keeping up with all the salty language.

      Last time I saw it they had changed back to the standard 1kHz bleep, though. Perhaps too many of the censorship fans didn’t like the non-standard bleep.

  3. +1 for the notch filter. I’m a broadcast engineer. I swear to the ability to activate my notch filter some days.

    How about decoding the closed captions, and then do the swear jar idea. Put it on HBO and you’ll be buying that new boat in no time.

  4. 1kHz is the frequency to which VU levels are calibrated. In a TV studio it takes quite a few more steps to mount a video tape and start playing it back than just whacking it into a VCR and hitting “PLAY”. The first few minutes of a video tape are usually filled with a color bar and 1kHz audio.

    Speaking of which, not only do I have a 1kHz notch in my hearing, my wife says I’m also incapable of distinguishing more than 8 colors and I organize the T-shirts in my closet in the only logical order I know: White, Yellow, Cyan, Green, Magenta, Red Blue, Black.

    By the way 3141 Hz is also common in some audio-related places (though not nearly as common as 1kHz). Exercise for the reader: why 3141 Hz?

    ===Jac :-)

  5. Nice idea. Still, I would prefer to mute the beep and maybe replacing it with a nice profanity sample of your own choice (or a radom sample of your personal “best-of” list). :D

    On a sidenote.. that 1kHz signal (usually at some nice high ampl.) is so distinct.. one might even get away with just some simple peak-meter style envelope tracking? Not meant as a criticism.. just a thought that crossed my mind while reading.

    1. On the “De La Soul is Dead” album, there’s some skits between the songs where they made fun of censorship by dubbing the word “Crocker” (a sample from the Kojak TV series), almost but not quite over all the curses. I still sometimes tell people “Let’s get the fsck crocker crocker!” when I leave the room. I imagine it should be possible to automate this with a 1kHz detector or caption reader :-)

    2. But by the time it is detected the word would be too late, you’d have to also have a delay in the audio, or rather a copy of the audio running slightly ahead. (Which with some players/receivers comes naturally.)

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.