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Sound waves and location? please help with my phantom!

  1. May 19, 2005 #1
    sound waves and location??? please help with my phantom!


    Here is my problem strange as it may be:

    I have an old piano which due to it's age and condition, when played, emits no musical notes or musical sound it is more of an attractive antique furniture piece than anything. However, of course if someone sits down to play it you can hear the keys as they are pressed but of course have no idea what tune is playing. This is where things get a little more scary you could say, you may not believe in ghosts but I do, so even if you don't believe in ghosts please do help me if you can. Basically at night, not every night but at night, in total darkness I have heard, at least once a month if not more, the keys of the piano as if someone is playing it, it is not extremely long but i would say long enough for a short tune. This has been going on for years, however this is besides the point ....... I want to know or at least get a good idea of what tune it being played ......... I was thinking that if I had a sound meter or perhaps a microphone, set in a fixed location, to capture these key sounds I may be able to determine which keys were being pressed. For instance I could set up a sound meter or microphone, not sure what equipment I could use or would be best? at a fixed location, say on to the far right of the keyboard and then record the sounds made by striking each individual note, I would assume if the equipment was good enough, each key would make a unique sound or the sound would have its unique power value? Also, I know the power of sound decreases with distance and thus knowing this I would think a person could calculate which key was being struck since the meter or microphone is at a fixed location as well as the keys? The location may not be exact or always right but i would think you could work out probabilities? Also, since each keys is at different distance from the meter or recorder I would think that if a person could capture how long it took the sound to travel from source to recorder, you could then identify which key was struck since the further away keys would take longer than closer ones etc. , although we are talking mili seconds I guess but i would think with computers such calcuations could be made? So, basically I want to know if this could be done and what method(s) could be used and equipment etc.???

    Thanks for any help you can provide, Michele
  2. jcsd
  3. May 19, 2005 #2
    Hahaha wait ok :rofl:

    Get a video camera that will work in low light and focus it on the keys. You can then play back the tape and wright down the notes....good luck. :rofl:

    Im guessing this will be moved.
  4. May 19, 2005 #3
    I agree with that advice. Your idea of recording the sound and trying to figure the distance from that is probably just about impossible in practise.

    The best reason to use a video tape is that you're almost certainly going to find the keys are being manipulated by some kind of pesky animal: your cat, a rat, a squirrel, a possum, etc.
  5. May 19, 2005 #4
    Get an audio recorder and just record the tune, then hand it to a musician.
  6. May 19, 2005 #5
    She said the piano doesn't sound anymore. All she can hear is the thump of the dead keys being pressed. She wants to know what tune is trying to be played, if any. If she could hear it, she could just hum it to people till she found one who knew what it was.
  7. May 19, 2005 #6


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    Whozum, there is no tune!

    I'll echo everyone else here; you're not gonna solve this with a microphone. The video camera seems to be the best solution here. Alternatively, with some imagination I'm sure you could come up with an elaborate system of sensors on all the hammers, and use some data acquisition technique to obtain time values for when each key was pressed. Wouldn't be easy though...
  8. May 19, 2005 #7
    Oh I'm sorry, I thought the piano was not workin but for some reason she still heard music at night. I've been watching too many horror movies I guess.
  9. May 20, 2005 #8


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    If you have a cat, that definitely is the most likely source. Any cat that I've had avoided the keyboard because it scared the hell out of them the first time they jumped up and it made a noise. Your keyboard, being silent, wouldn't intimidate one and might even be fun for it because of the springiness. Once you identify the cause, and if you want to stop it, I would recommend keeping the lid closed at night.
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