lowest audible frequency?

Discussion in 'Archived Threads 2001-2004' started by PaulDF, Oct 22, 2002.

  1. PaulDF

    PaulDF Second Unit

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    Just wondering what would be the lowest audible frequency by human ears. Around 18-20 hz? Also at what point does a frequency start to become locatable (for lack of the proper word). I had thought around 75 hz, but probably lower? Thanks.
     
  2. Dustin B

    Dustin B Producer

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    Lowest audible frequency depends on the person, and how loud it is. Not many subs can play below 20hz loud enough that the people who could hear it if loud enough can. But yes at ~20hz is where people stop being able to hear the sound and instead feel it.

    The point at which you can localize a frequencies direction, I don't know for sure. I think it will depend a lot on the placement and quality of the sub, if it generates significant harmonics and/or is placed poorly, it will be easy to locate even at very low crossover frequencies. If it's a good sub well placed, 80hz crossover will be no problem, you could probably even get away with 100hz.
     
  3. Brandon_M_S

    Brandon_M_S Agent

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    i believe all things being equal, 20hz is the lowest audible sound, and i *think* anything lower then that, you start feeling it more then hearing it.
    [​IMG]
    brandon
     
  4. Shawn Solar

    Shawn Solar Supporting Actor

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    like dustin said it also depends on if it is loud enough. I heard that 20hz is not really audible until 75db where as 1khz is very audible at 75db. hearing also degrades overtime. at 15-18yrs old a person can probly hear down to 20hz but as you get older it starts to take a decline.
     
  5. Nick V

    Nick V Second Unit

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    Doesn't it matter how big of a room you're in? If your room is the same size or bigger than the wavelength, won't you be able to hear that frequency no matter what?

    20Hz is about 56ft. right?
     
  6. Dustin B

    Dustin B Producer

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    Nick, I don't think you are talking about room modes, but the myth that the room has to have a dimension longer than a wavelength in order for the sound to be heard.
    If that is the case please read this thread:
    http://www.hometheaterforum.com/htfo...eed+sound+1130
    Humans have a range of frequencies they can detect. It varies from person to person though. Some people can hear 20.5khz, some people can't. Some people can hear 18hz, some people can't. Also some peoples threshold for detection of 18hz will be at a lower level than someone else. In other words one person maybe able to detect a 18hz tone at 95dB while another person needs it to be 105dB before they detect it. All of this has absolutely nothing to do with the room you are in.
    The room can greatly affect the over all frequency response of your stereo though. Room modes can cause huge peaks and valleys in the response (modes). And the smaller the room, the more gain you will get in output in the last few octaves.
     
  7. Brandon_M_S

    Brandon_M_S Agent

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  8. Dustin B

    Dustin B Producer

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    Yep, low end, amount of gain increases as frequency decreases.

    I don't remotely understand how the physics of room gain work. Just know they do and that the smaller the space gets the larger the amount of gain and the higher in frequency it starts to occur. It's why car subs can have such a high Fs and start their roll off so high. The tiny car cabin provides huge amounts of gain down low.
     
  9. Ned

    Ned Supporting Actor

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    Hearing loss only occurs at the top end, so even when you're an old man you can still enjoy thunderous bass [​IMG]
     
  10. Chris PC

    Chris PC Producer

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    Perhaps the person is asking what the lowest recorded "audible" frequency is. I guess you'd then need to combine that with the exceptional person who heard the frequency that low. What I mean is, there is probably a person out there who can hear really low, loewr than most people.
     
  11. Dustin B

    Dustin B Producer

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    Well in that case some of Telarc CDs have some ridiculously low frequencies at significant levels (3hz or 5hz or something like that). I believe there is one recording of the 1812 Overture in particular.
     
  12. Bill_Weinreich

    Bill_Weinreich Second Unit

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  13. Dustin B

    Dustin B Producer

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    I've dropped a few jaws with the recording of the 1812 overture I have and my Tempest tuned to just over 16hz [​IMG]
     
  14. Jason Wilcox

    Jason Wilcox Supporting Actor

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    as shawn said...we aren't very sensitive to low bass at low volumes....but as the volume goes up past 85db our hearing response begins to flatten out....i think we are most sensitive to 4khz sound
     
  15. PaulDF

    PaulDF Second Unit

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    Wow. That more than answers my question. I was pretty close with what I thought, but as always I learned a little extra. Thanks all!
    And no Chris PC, "the person" didn't want to know the Guiness record for hearing the lowest frequency...(thanks for taking the time to scroll up to my name...)
     
  16. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Here's something on my mind,

    a 15hz slam creates a bundle of sonic waves that can be felt by your body. Your mind then might process these sensations and change them to sound because basically sound is simply moving air.

    The widest, deepest and loudest SPL ever could have been at ground zero of a Nuclear bombo exploding. Or perhaps if we were able to measure the air speed during the implosion of a planet or star. Or the movement of particles in a blackhole with moving dark matter. One things for sure is that there are probably louder SPLs than what can be measured.

    On the other hand, there are some crabs that click their claws to create sonic waves that knock shrimp senseless. They have special claws that cock back like a pistol and then fires an air bubble so fast that the air implodes and reaches an instantaneous temperature exceeding the surface of the sun.

    Now that's some serious hit if that air bubble was to hit a human ear drum.
     
  17. Larry B

    Larry B Screenwriter

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    Chris:

     
  18. Tom Vodhanel

    Tom Vodhanel Cinematographer

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    It was discovered a while back that felines *purring* increased recovery time for them if they were ill or injured. Some hospitals actually started experimenting with low freqs with humans to promote quicker healing...but I don't remember the details.

    House cats purr in the mid 40s, a bobcat was in the mid 30s and the big kitties...like the mountain lion was in the mid to upper 20hz range.

    TV
     
  19. Jeff_M

    Jeff_M Stunt Coordinator

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    Tom, perhaps you could start equipping hospitals with SVS? Nurse, I need 115db's of PC+, STAT!
     
  20. Lewis Besze

    Lewis Besze Producer

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    I think it is actually 16hz as the "threshold" of the human hearing.
    And yes age won't have an effect on it, like it does on the upper end of the spectrum.
    Dustin,
    regarding room gain,I'm no expert either, but my understanding is that,the larger the room,the lower the frequency,as when it is come to "play".One of the reason why larger rooms have a hard time to get real bass,like in the cinemas[below 30hz].
     

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