1

I was familiar with this phenomenon since my childhood. But I got curious about it just recently.

For example, imagine you are in a restroom with an air conditioning fan which produces sound while spinning.

When you move your head repeatedly right and left and/or up and down you perceive the sound in two different pitches (for example, F,G,F,G,F,G,...)

I suspect this is because of the change in the direction of fluid in the inner ear. But even in a high speed moving of the head you can still experience the phenomenon; And I think may be the fluid isn't the cause at the same time, because it doesn't have the time to change direction in high speed head movements.

But why do you only hear the sound in two pitches? For example, F when your head points to the right; and G when your head points to the left. Why you can't hear a third pitch either?

Update: I searched the internet and found this. But still don't know the reason.

I just think it's weird that I can change tone of low frequency sounds like computers and fridges by turning my head slightly left or right and they get louder.

8
  • I don't perceive a pitch change when I do that. Are you sure this isn't unique to you?
    – Carey Gregory
    Jul 15, 2023 at 21:09
  • I'm currently in front of the cooler fan in the living room (about 3 meters away). It has a regular sound when my face is in front of it and somehow when I move my head to the left. But I perceive a slightly different sound when I move my head to the right (addition of a second sound to the previous sound). The changes become more noticeable when I move my head repeatedly. Jul 15, 2023 at 21:45
  • Well, you describe changes in pitch in notes, so maybe your ears are more musically trained than mine.
    – Carey Gregory
    Jul 16, 2023 at 2:56
  • Pitch is not a musical-exclusive thing. It denotes the change in frequency of the sound perceived. A child's scream is also in a different frequency compared to an adult's shouting. Jul 16, 2023 at 16:15
  • 4
    I think I'm missing something here, but aren't you just describing the Doppler effect?
    – M.A.R.
    Jul 19, 2023 at 17:06

1 Answer 1

3

As @M.A.R. mentions in the comment thread to your question, this is nothing but the Doppler effect.

When you close the distance to an object emitting sound, the next sound wave hits your eardrum faster than it would if you'd stay stationary (same applies to the sound-emitting object moving towards you, like an ambulance). Hence, even though the frequency emitted is lower, it appears higher to you since you hit the sound waves in higher frequency due to your movement.

The opposite happens when you move your head away from the object: you delay the next wave hitting your eardrums as the sound wave needs to catch up with your moving head first. The result is that the tone appears as if it had lower frequency than that at which it is indeed emitted.

Since ears can be very sensitive towards pitch change, this effect can be experienced even when you just move your ear towards or away from a sound emitting object fast enough. When experiencing this by turning your head, this suggests your experience is created because of one ear being significantly more sensitive than the other one, since otherwise, they'd even out. I'd check with a doctor if I were you.

1
  • My mother has an inherited ear problem and I think I also inherited it from my mother! (She has sticky inner ear) The link I recently added to my question is also from a person with ear problem. Sep 11, 2023 at 21:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.