how do we understand sound

Discussion in 'Off-Topic' started by Lightfire, May 21, 2012.

  1. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
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    hi,

    i know little about sound.. i understand it is a vibration, and varies by pitch, sound . but how can we understand "hello"? i mean in radio, eg. FM, it is modulate by freq. but how we understand the sound "hello"? sorry i can't explain it further .
     
  2. maxpower097

    Well-Known Member

    Feb 20, 2009
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    as a wave form. All sound is waves. waves hit your ear drum which is super sensative and that produces electrical signals to your brain creating sound. One cool experiment I did when I was like 7 or 8 was to get an old LP record. Roll a peice of paper into a funnel and glue or tape a sewing needle to the small end. Spin the record with the needle and it actually produces sound. You could probably make something to experiment with like this and learn a couple things. In anycase its just fun kitchen science to do. Like vineger and baking soda/ Mento's and diet coke. This experiment shows how analog sound works. For digital they basically just take all the peaks and valley points and decode it the same. So you don't get the full wave form, just the highs and lows. Thats why sound people are still all about analog and the warm sound it produces. When you convert analog to digital you actually loose a lot of data, but much of that data is noise.
     
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  3. bretm

    Member

    Feb 6, 2012
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    Sound is pressure waves, and hearing is primarily based on sound, but it's ferociously complicated and the brain also incorporates visual cues and probably other information. See, for example, the McGurk effect.

    If you look up how to train a neural network it might give you some sense of how our brain learns to understand sounds.
     
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  4. studiot

    AAC Fanatic!

    Nov 9, 2007
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    If you mean speech then you might like to consider this.

    You have already observed that sound varies in pitch. Indeed we can tell "hello" whether it is spoken by a man or a woman, whose speech is of very different pitch.

    In fact the information in speech is not carried by the vibration shape or pitch it is carried by a sort of digital code we call phonemes, which simplified are pulses of sound and it is these pulses that we hear as speech.
     
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  5. Wendy

    Moderator

    Mar 24, 2008
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    I remember the demonstration of a variable speed motor and a wheel with evenly spaced holes in it. You blow the air though the holes as the wheel turns, and you hear sound as the air puffs through the holes. Vary the speed of the motor, and the pitch (or tone) changes. This is the most basic way of making sound.
     
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  6. #12

    Expert

    Nov 30, 2010
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    Don't forget phase shift. Humans don't seem to get any information from absolute phase (that's why it doesn't matter where a Leslie speaker stops), but the phase changes in words are part of the information. When meeting a person with a different acccent, the first word is usually lost because the brain isn't expecting that particular phase shift, so it fails to interpret the first word.
     
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  7. maxpower097

    Well-Known Member

    Feb 20, 2009
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    I'm gonna try that it sounds pretty cool.
     
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  8. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    I destroyed the high frequency response of my hearing. During one test, the doctor stated a word and I was to repeat it back to him. As the doctor was reviewing my results, I told him I knew my response was terrible above 1 kHz. He asked how I knew what 1 kHz sounded like, I told him it was a common frequency used in radios for testing. He told his student aide that most people were not like me and that she would be explaining in detail about the loss. He did give me a sample of what he said and what I said ... boy was I way off. He did explain that the small bone, the one that resonates to higher frequencies, was gone.

    My wife finally understood why I sometimes didn't understand what she says.
     
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  9. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
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    Hello!

    Very good answers! But what pitch and frequency would make the tone "Hello"?

    E.G. You talk to your new class mate and you say "From what school are you from?"

    What combination of pitch and frequency would make the tone "From what school are you from"?

    I believe it is more than frequency and pitch?

    I do make tones using audacity it's great ! i do make 1000 hz sine wav for my NTSC signal test! xDDD
     
  10. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Pitch and frequency are words that mean the same thing.

    Pitch is a musical term, frequency is a physics term.

    You are right that the word is more than just a collection of sounds of different frequencies - what did you make of my post#4?
     
  11. bertus

    Administrator

    Apr 5, 2008
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  12. maxpower097

    Well-Known Member

    Feb 20, 2009
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    Me 2. I used to follow bands so I've seen probably near 500 concerts. I hear fine but I was stunned at work one day when a coworker whipped out one of those sound testers. Everyone in the office even the 50 year olds could hear 18,000, 16,000, 14,000. I forgot where I started hearing it but it was way after everyone else. Everyone was like really? You can't hear that? I was just thinking damn.... I screwed my hearing when I was young.
     
  13. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Loosewire,

    If you use windows media player, and show the bars, that is a graphical analyzer. there are plenty of "hello" wavs or you could record the loosewire.hello.wav on your computer and analyze your own hello. I won't vouch for the accuracy of that because I hadn't swept it ...
     
  14. justtrying

    Active Member

    Mar 9, 2011
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    you may find this interesting http://www.pcworld.com/article/16276/how_it_works_speech_recognition.html

    In regard to humans, we learn rules of common language. Unless we know the language, "hello" is meaningless, it will be heard but not understood. For how sound is interpreted, brain is very important in tuning out noise. Why humans cannot be replaced by a machine http://www.ucsf.edu/news/2012/04/11868/how-selective-hearing-works-brain

    What always fascinated me is music, there seems to be a common thread through all cultures of musicality and of what people find important in music - beat for example. Doesn't matter where you are from, you will understand the beat...
     
  15. JoeJester

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    Apr 26, 2005
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  16. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010
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    where's loosewire
     
  17. #12

    Expert

    Nov 30, 2010
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    Somewhere near Miami Florida.
     
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