Where to Find a 22000-25000hz Speaker w/high DBA

Discussion in 'General Electronics Chat' started by Bueller, Mar 6, 2009.

  1. Bueller

    Thread Starter New Member

    Mar 6, 2009
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    I am trying to find a speaker capable of putting out at least 140dba, but would prefer higher. It needs to be able to emit 22000-25000hz range. I am trying to build a speaker to run constantly putting out sound in that range. I really dont know here to start. Any help would be appreciated.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    You would need a turbine or rocket engine to generate that level of sound!

    What are you attempting to accomplish? Kill all neighborhood pets inside a mile radius?
     
  3. Audioguru

    New Member

    Dec 20, 2007
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    Very poor quality rock speakers use a piezo tweeter that might still be available. The frequency response has many peaks and notches. I call it a whistle.

    With an input of 64W, a distance of 1m and at normal audio frequencies the sound pressure is 112dB.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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  5. Bueller

    Thread Starter New Member

    Mar 6, 2009
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    Thanks for the responses. I am trying to prevent a dog from continually leaving me 'presents' all over my lawn. I feel like I am navigating a mine field just to get to my mailbox. And I have lost the game several times, once with brand new just out of the box Nike's. I didnt think 140 decibels was that high, but I guess I am wrong. A jet engine would be great, but unfortunately in my town we have an ordinance against running jet engines after dark. Assuming I do get ahold of the speaker, what would I generate the sound with? I am not to familiar with electronics. Thanks again.
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    That cheap crappy piezo tweeter might not have any output at 25khz. At lower frequencies its output is deafening when its input is 50W. You will be sued by the neighbours.
    Squirt water on the dog.
     
  7. Norfindel

    Active Member

    Mar 6, 2008
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    I have seen some industrial ultrasonic transducers on the web that are able to output 40 KHz at high pressure levels. I'm not sure how's that measured, however. Take a look: http://www.macsemi.com.ar/pdf/40tR-12.pdf

    I don't know how this things are used, however. I assume you just drive them with 30V rms like it says there, but it's strange to me that the impedance is 1k minimum. Does that means that it can deliver that kind of ultrasound with only 0.9w ?
    I readed somewhere that large or old dogs aren't as sensitive to that frequencies, or just not at all. I also seen a table that listed what things you can kill with enough pressure levels of ultrasound, so it can even be dangerous if not used right.
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    The sound pressure spec for the Taiwan transducer does not specify a distance. Maybe it is very loud when you wear it on your ear. Sound pressure decreases with distance.

    It is a resonating tuned whistle so of course its input power is low. It is loud only at a single frequency.
     
  9. Norfindel

    Active Member

    Mar 6, 2008
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    I found the manufacturer's page. They say that's measured at a distance of 30cm: http://www.ctdco.com.tw/ultrasonic_sensor.htm . It's ridiculous that piece of information isn't on the actual datasheet, however.

    According to this calculator, it should be still pretty annoying at 15m, for something that can hear it: http://www.sengpielaudio.com/calculator-distance.htm http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm

    I suppose this cannot have any effect on humans, right? Even after continuous exposure?
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    A Piezoelectric transducer tht is driven at the proper frequency and power could frighten of a dog and so would a shock wave inducer.
    I heard of it, that could burst out air waves tht would induce shock to any one with in the range.

    ****
    Rifaa
     
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