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How does a speaker diaphragm produce the sound of 2 instruments at the same time ?

  1. Nov 3, 2008 #1
    I am quite confused how a speaker can produce two or more different frequencies at the same time ?

    Let's consider one instrument to be the thud of the kick drum
    Let the second instrument be a Shakuhachi flute. (From Enigma Sadeness)
    Let us have only one speaker( like in most of the headphones)

    Now how is the speaker able to produce the sound of both the thud & the flute at the same time ?

    Considering the sound of the flute to be 5KHz, and the kick drum to be 100Hz, how is the speaker able to move at both frequencies at the same time ???
     
  2. jcsd
  3. Nov 3, 2008 #2
    Re: How does a speaker diaphragm produce the sound of 2 instruments at the same time

    You can have vibrations superimposed on one another.
     
  4. Nov 3, 2008 #3
    Re: How does a speaker diaphragm produce the sound of 2 instruments at the same time

    They cant. As jaap de vries stated, you can only superimpose frequencies with a single speaker.
     
  5. Nov 3, 2008 #4

    marcusl

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    Re: How does a speaker diaphragm produce the sound of 2 instruments at the same time

    You can decompose any acoustic waveform into a sum of pure tones. This is called Fourier analysis, and it rests on the principle of superposition: you can simply sum up independent signals to get the resulting output, so long as the system is linear.

    That is exactly the case you are asking about. The speaker output is the superposition of two frequencies, and your ear performs the Fourier analysis to separate the tones. This breaks down if the system turns non-linear (i.e., if you turn the volume up too high the sounds get distorted and fuzzy. You hear distortion products that aren't present in the original signal.) All is good when the system is linear.
     
  6. Nov 11, 2008 #5
    Re: How does a speaker diaphragm produce the sound of 2 instruments at the same time

    The signals (in this case, the pressures) of both instruments add in the speaker just as they already added in the amplifier, in the microphone, and in the air - and as they add in your ears.

    The miraculous part of the operation is not that they add, but that your brains is capable of separating them. This is something machines do very badly.
     
  7. Nov 17, 2008 #6
    Re: How does a speaker diaphragm produce the sound of 2 instruments at the same time

    You can also consider than your ear is decoding this complex waveform while using only a single diaphragm (not counting your other ear).
     
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