Re: [ARSCLIST] Not using headphones

[Dnjchi@xxxxxxx]

In a message dated 8/26/2006 2:33:59 PM Eastern Daylight Time,  
pattac@xxxxxxxx writes:

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



Might this phenomenon also apply to those wearing hearing aids?
 
Don Chichester