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Dispelling the 'Myth' of the Missing Fundamental

  • 1.  Dispelling the 'Myth' of the Missing Fundamental

    Posted 01-22-2024 03:17
    • Dispelling the 'Myth' of the Missing Fundamental
    • Video Presentation YouTube Link: 
    • https://youtu.be/Gj0xobcBpdM
    • There is a widely held 'myth' called 'the missing fundamental' in the bass register of a piano. 

    • * This myth is very unfortunate and very untrue.
      * I am here today to dispel that myth once and for all with irrefutable evidence. 
      * Is the fundamental present all the way down to A0. Of course!
      * This evidence was collected from a PianoSens sensor on a large concert grand, a Fazioli F308. However, I did a similar experiment over 15 years ago using an instrumentation quality microphone on a Steinway D and got a similar result.
      * As you watch the video and hear the explanation, you will clearly and unequivocally see that there are clean, pristine periods of repetition at the fundamental frequency all the way down to A0. 
      * You will see the spectral view of the time domain showing that the fundamental A0 is down only 9 dB from the 2nd harmonic A1. A factor of 9 dB is still very easily heard by human perception even at that frequency.
      * I also show just how 'messy' the transient response is from the hammer strike moment, compared with the PianoSens sensor.


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    Steven Norsworthy
    Cardiff By The Sea CA
    (619) 964-0101
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  • 2.  RE: Dispelling the 'Myth' of the Missing Fundamental

    Registered Piano Technician
    Posted 27 days ago

    Yes, there is a string vibration at the fundamental frequency, as Scott Murphy showed in a high speed video, looking at the string at the bridge pin. He also demonstrated that the bridge pin moves at that frequency. However, audio analysis shows that the fundamental frequency as heard (by a microphone, or by the ear) is very weak, really imperceptible among the various upper partials. Presumably the weakness is due to the soundboard/bridge system's inability to project that frequency.

    So, yes, the pianosens sensor is verifying the presence of the vibrational frequency, but that doesn't mean the fundamental is present for practical purposes (ie, heard by the ear). Your "proof" applies to string movement, as that is what pianosens is measuring. String movement is not sound. 

    Sound at the fundamental frequency can be present in large pianos, but it is so weak that we can say that it is essentially missing relative to the rest of the spectrum.



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    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
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  • 3.  RE: Dispelling the 'Myth' of the Missing Fundamental

    Posted 27 days ago

    Fred,

    Didn’t you see the mic results also? I think you did not follow me. I re-did the mic experiment that I did 20 years ago, same result. As a matter of fact, the mic experiment showed that the ratio of the fundamental to 2nd harmonic was even a little greater that it was with the sensor, furthering my point.

    My major frustration with the PTG forums is 'lots of conjecture and opinions' but 'lack of experimental data'. 

    Steve