Re: [ARSCLIST] Not using headphones

[George Brock-Nannestad <pattac@xxxxxxxx>]

From: Patent Tactics, George Brock-Nannestad

Dave Bradley observed:

.............
> 
> I noticed years ago that when I was removing headphones while the 
> program was still playing that there was a dopler-like shift in 
> pitch. The shift stayed in place, though, even when I held the 
> headphones still. It seemed that the distance affected the pitch, not 
> the motion of moving them away. I have to wonder if there is 
> something involved on a smaller scale that makes the sound slightly 
> higher in pitch when it's closer to the ears. That might explain why 
> people would sing not in tune when using headphones....

----- this is a well-know phenomenon, at least by acousticians. S. S. Stevens 
described this as early as 1948. We cannot reproduce his graph here, and the 
curves are not linear, but let me read some figures off it:

5 kHz increases 6% in perceived pitch going from 50 to 90 dB
2 kHz is not much influenced
 300 Hz decreases 6% in perceived pitch going from 50 to 90 dB

(these percentages are about a semitone!)

above and below these, the effects are more marked.

This explains a lot of things, such as perceived distortion and Dave's 
observation.

Kind regards,


George