Headphone pitch phenomenon

October 30, 2012 3:18 PM

If you take off a pair of headphones and lay them down somewhere, the music sounds like it's in a different pitch than when they're on your head. Why?
posted by facetious to sports, hobbies, & recreation (7 answers total)

"Apparent Frequency Change With Intensity" might explain it.
posted by Aquaman at 3:21 PM on October 30, 2012

My first thought is to the Doppler Effect.
posted by MansRiot at 3:43 PM on October 30, 2012

I think it would have more to do with the size of the speakers in headphones than anything else - they are too small to project bass frequencies very far. It's not that the music it at a different pitch, it's that all of the low end is missing.
posted by InfidelZombie at 3:46 PM on October 30, 2012 [6 favorites]

The Doppler effect is a product of the sound being in motion, its not in effect here.
posted by bitdamaged at 5:07 PM on October 30, 2012 [2 favorites]

Apparent Frequency Change With Intensity" might explain it.

When I first listened to the linked sound-files with louder and softer tones I thought, "holy cow! it sounds like a full half-step difference!"

Then I read the context more carefully and saw that the tones in the demo aren't actually the same.

"the weak first tone in a pair is always exactly the same. But the following strong tone is successively rising in frequency, by 0, 20, 40, 60, 80, and 100 cents respectively."

So the idea of the demo is that they gradually change the pitches so you're supposed to find when they match. The effect didn't work for me (the pair that's supposed to be the same sounded the same) so I wonder if musical training is supposed to make the effect go away.

Doppler effect can't explain what the question is talking about, which is I presume stationary headphones and a stationary ear. I think Aquaman's suggestion is the right one even if I couldn't hear it. Then again, I can't really find anything solid on google scholar about it. Closest is this: http://psycnet.apa.org/journals/xap/8/1/17/
posted by spbmp at 5:14 PM on October 30, 2012

InfidelZombie has the answer. Small drivers like in headphones project high notes much better than low ones. This is fine when they are close to your head, but take them off and you can't hear the bass so they sound tinny and weird.
posted by Scientist at 5:32 PM on October 30, 2012

I don't know if this is true or related, but if an opera singer needs to sing off stage yet still be heard, I was told they have to sing a semitone or so above what is written to counteract the effect of being further away and to fit in with the rest of the music.

Would this be the same thing or is my contribution entire nonsense!
posted by stenoboy at 1:46 AM on October 31, 2012