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How to give speech a Donald duck effect?

  1. Nov 4, 2012 #1
    Hi PF,
    I read that in the communication engineering book by simon haykin saying that if the phase response of the voice signal is altered we can get the donald duck effect. But how should I play with the phase response. Any advice.

    -Devanand T
     
  2. jcsd
  3. Nov 5, 2012 #2

    sophiecentaur

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    A poor SSB demodulator will give a good 'donald duck' effect. If you have a DSP program then you could arrange that quite easily. However, I'm not sure that a simple 'messing about' with phases would do what you want - more like frequency shifting would be needed. Inverting the frequency spectrum of the audio could do it, perhaps - easy to do, once you have DFT'd a short passage of speech.
     
  4. Nov 5, 2012 #3
    I have the strongest doubt about our ears detecting any phase. I had made a software to synthesize a sound from its harmonics (...hence only periodic sounds... I had been fooled by Helmholtz' initial mistake) that could adjust each phase individually and that made zero difference for the ear, nada, niente, nitchevo, walu.

    Though, I haven't still checked if we locate a noise source by the phase difference between our ears, so I could still accept this allegation.

    De-tuned SSB lets the local oscillator beat, hacking the received signal quickly. This deforms the voice for sure. >30 years ago a hobbyist paper proposed a phase inverter driven by an oscillator to do this on voice and instruments. On electronic pianos then, the "chorus" effect was obtained this way; it sounded more or less like several instruments playing not exactly in tune.
     
  5. Nov 6, 2012 #4

    sophiecentaur

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    If it's tuned the 'wrong side' it will invert the audio frequency spectrum, too.
     
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