Out of Phase sounds (crickets)

Discussion in 'Archived Threads 2001-2004' started by Chris Tsutsui, Apr 11, 2002.

  1. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I was walking to my car and I noticed a constant chirping/ringing from a field. It sounded like a mass of crickets and I couldn't localize or find a single cricket. The crickets (or noise making insects) must be producing an out of phase noise by rubbing their legs together. This way predators can't find them while they make their loud calls.

    But that leads to the idea that crickets can sense "out of phase" sound and and find the source. Because afterall, arn't they doing mating calls to attract others?

    So crickets can't experience home theater like we do because everything out of phase will be localized right in front of them.

    Too bad for them I guess.
     
  2. BrianW

    BrianW Cinematographer

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    Crickets, unlike their predators, don't percieve sound with only two ears which can be influenced by phase and direction. Crickets, like most insects, hear with their legs, wings, skin, and tiny hairs that cover most of their bodies. Their auditory systems are influenced much more by proximity than by phase or direction. Their home theaters would consist of a single full-range couch-thumper.
     
  3. Jason Handy

    Jason Handy Second Unit

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  4. Julie K

    Julie K Screenwriter

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    Only some insects have hairs on their body to sense vibrations. Crickets indeed have two eardrums located behind the 'knee' on their front legs. Ears are sometimes quite difficult to find on insects as they have them on legs, antenna, or elsewhere on the body.

    There is a species of mantid that the males have only one ear located on their body. This is thought to help the male avoid bats while flying around looking for a mate. The female has no ear.

    The small fly, Ormia ochracea, which is parasitic on crickets, has the best known directional hearing. It has two ears and can differentiate sounds by 2 degrees. That's better than we can do and we are certainly not bad at all in this category.
     
  5. BrianW

    BrianW Cinematographer

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    Julie, as always, your expert contribution is kindly appreciated. I happily stand corrected regarding the cricket's auditory senses.
    That's what I get for using Pinocchio as a basis for entomological studies. (But to my credit, if Jimminy hadn't worn those elbow patches, I'm sure I would have seen those ears of his.)
     
  6. Holadem

    Holadem Lead Actor

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  7. Vince Maskeeper

    Vince Maskeeper Producer

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    Actually this idea of phasing and polarity in cricket noises is also a bit misguided.

    In order for a signal to be "out of phase" - there actually must be more than one signal. So, the cricket would have to be creating two or more signals at the same time in order to have one and then have a second to be "out f phase" with the original.

    While this is not impossible- the problem is you have applied the concepts of localization in a STEREO environment to the idea of crickets. In your HT system, 2 signals in reverse phase from one another will not be able to be localized- when orignating from two DIFFERENT points in the room.

    The problem is, the cricket- even if he created 2 different signals with his legs-- they would origninate from the same mono point. Try feeding a signal and an out of phase signal to a single mono point (like your center channel for instance)- you will get silence as the two inverted waves would cancel one another.

    So, unless multiple crickets could come together to create the exact same sound- in exact reverse polarity - from two points in a field-- you wouldn't be getting the issue of phase localization that you are assuming.

    -V
     

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