Goofy tone phenomena

[Blumlein 88]

This might be interesting.

Attached is a zip file that opens into a 90 second mp3. Right channel is 440 hz at -20 db. Left is 442 hz.

Try playing this file, and move about. You can hear the warbling 2 hz difference if you are stationary. If you move at a normal shuffling or walking speed side to side the warbling goes away. Sort of works going forward and back as well. Also works if you twist your head right and left at the right rate.

 

[RayDunzl]

440 and 442 Hz

Approach the 440Hz speaker and depart the 442Hz speaker at a rate where the Doppler shift changes both to the same intermediate frequency and there's no longer any warble to hear.

https://www.omnicalculator.com/physics/doppler-effect

Ok, so the answer won't be my guessed 441Hz, but it is close. I leave it to the mathematicians to figure the exact frequency.

0.778m/s is your speed relative to the speakers.

Not goofy.

Physics.

 

[RayDunzl]

Put on headphones and play 440Hz in one ear and 442Hz in the other.

Then your brain gets all goofy and creates the warble where there is none in the air or at your eardrums.

 

[Blumlein 88]

440 and 442 Hz

Approach the 440Hz speaker and depart the 442Hz speaker at a rate where the Doppler shift changes both to the same intermediate frequency and there's no longer any warble to hear.

View attachment 10252

https://www.omnicalculator.com/physics/doppler-effect

Ok, so the answer won't be my guessed 441Hz, but it is close. I leave it to the mathematicians to figure the exact frequency.

0.778m/s is your speed relative to the speakers.

Not goofy.

Physics.

Yes, I knew it was a doppler thing. Was still a fun experience. Thanks for getting the relative speed needed to make it work. For extra credit repeat with doppler beating against the ceiling fans while turning.

 

[RayDunzl]

Yeah, I think about that sometimes.

We never figured it out, or if we did, I forgot...

The ceiling fan problem: https://audiosciencereview.com/forum/index.php?threads/close-in-jitter.1621/page-15#post-41686