Noise Cancellation Project Idea

Discussion in 'The Projects Forum' started by supedave, Feb 27, 2010.

  1. supedave

    Thread Starter New Member

    Feb 27, 2010
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    I am brand new to circut board projects, and I have an idea. The thing is that I have no idea how to start off.

    I want to make a noise cancellation device. I want to be able to plug headphones into this device, and be able to plug in the device to some sort of audio scource. The audio scource simply passes through the device, and the device injects the inversed phase to the headphones.

    I am familliar with the phase cancellation concept, and how it plays into active noise cancellation. I just have no idea how to impliment it.

    From what I know, I need a microphone, whatever chip that inverses the phase of the wave, a way to integrate a calibration knob, and a power scource.

    I need beginer level stuff, seeing as this is my very first project. I need everything from where to get the parts, to how to put them together, to what exactly they do and how they do it--the works.

    Thanks in advance,
    Superd@ve
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
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  3. supedave

    Thread Starter New Member

    Feb 27, 2010
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    Well, I'm looking for something along the lines of making a box that can cancel sound in an everyday scenerio. Say, like, where i can listen to my own music on my iPod without being able to hear my parent's music that they are playing over the car stereo.

    I would really like to make it myself, and not buy it, because i think it would be fun, and I could use it as bragging rights.

    I also want a way to block out my parent's music...

    Thanks,
    Superd@ve
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
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    Oh jeez. I remember those days. There is a better way.
    Learn to appreciate all music and you will find a bond with just about anyone you come across in life.

    With the quality of music being made these days, I would give the device to your parents! :D

    Ok. So this is no where near as easy as one would think. You must know the frequency response and special nuances of the headphones to be sure they are reproducing the EXACT phase reversal of the offending noise. If not, you will just hear your parents music louder. Also, you have to be sure that you subtract the phase from the music you want to hear to be sure if the same frequencies are used in both, your music won't be canceled too.

    Have you any amplifier experience yet?
     
  5. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    In a car, there will be lots of reflections, plus it is likely to have at least two speakers. What's important is the phase at your ear, not the phase at the source. That's why Bose uses a pick-up right in the headphone. I suspect you will need to take that approach, rather than plug into your parents radio. I recall seeing some projects on the Internet, but don't have the links handy right now.

    John

    It Internet if full of the $20 video that simply uses passive noise blocking. But, here is one DIY project that actually uses inversion: http://gilmore2.chem.northwestern.edu/projects/noise_prj.htm
     
    Last edited: Mar 15, 2010
  6. supedave

    Thread Starter New Member

    Feb 27, 2010
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    Hey, Thanks jpanhalt. That's exactly what I'm looking for.

    I Do take this in consideration, and I wonder if Incorporating a knob that will change the velocity of the inversed wave to help match both waves more efficiently.

    Well... I learned about phase inversion when training on the sound board at my church...
    In regards to circut board projects and using amplifiers there, I have none. this is my first project.

    Thanks,
    Superd@ve
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
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    Well you sure are jumping into it with both feet. You have found a great resource here. You should read the eBook chapters at the top of every page. The book will teach you much. And anything you can't seem to wrap your head around, bring it to the forums.
     
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