Human Hearing vs Phase Changes: Demonstration

I’ve often asserted that the human ear is a frequency sensor, and phase changes or phase distortion don’t affect hearing. It’s high time for a demonstration!

When Single Sideband (SSB) is implemented using the filtering method, the phase gets rather distorted. However, with the phasing method, phase information can be preserved. Some say that means better quality audio. This video demonstrates changing the phase between a fundamental frequency (256 Hz, about Middle C) and the 2nd harmonic (512 Hz, about High C). See if you can tell the difference. It’s obvious on the oscilloscope, but no matter the phase difference, it all sounds the same to me!

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3 Responses to Human Hearing vs Phase Changes: Demonstration

  1. Dave says:

    Tom, my organ has a way to emulate a “feature” of pipe organs, which is that the more keys are pressed, there is a slight pressure variation in the air chest, which results in very slight detuning of some of the pipes. I should have turned that feature off. Personally, I think it creates a richer sound, but I fear that may have created the beat note you heard. 73, Dave

  2. Bob Hill KC5IQZ says:

    I can hear the tone moving to a more sharp pitch as the sound proceeds. But I’m a trained musician with sight singing, ear training experience. I Dave, I enjoy and appreciate your videos. Thank you so much for sharing your HAM experience.

  3. Tom Field says:

    It seems to me I can hear a beat note when you play middle C and high C on the organ, but can’t make one out when you use the test tone generator. As you say I get the idea that there is something going on, but can’t make it out. By way of background, I’m 62 and have some high frequency hearing loss.

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