I *personally* think it has something to do with the total RMS power able to reach the ears and the fact that the headphones may be tuned to compensate for the frequency response of being used directly over the ear.. It seems like it would be something like listening to a speaker in an enclosure, then removing it from the enclosure and letting it play in the open air. There is a definite change in the sound without the enclosure. I believe the audio guys over here agree that the ear canal resonates at 2-5Khz, depending on the individual, so that would probably be enough to change the percieved pitch and make it seem higher when you put the phones on. Then theres always the phase cancellation of the two speakers facing each other. Rob > ** Original Subject: RE: Headphones changing pitch automagically [OT] > ** Original Sender: Wagner Lipnharski > ** Original Date: 8 Apr 2000 00:53:58 -0000 > ** Original Message follows... > > The original post says clearly: > "...Then I take the headphones off and hold them away...", it means to > me he is NOT moving the phones, just holding them away, so, it is > impossible for doppler effect if the distance is fixed along the time. > Why the thread divert so much? probably in few days we will be talking > about the chicken counter in Australia is generating the pitch change at > his hearphones... :) > Wagner. > > David E Arnold wrote: > > > > This is known as the "Doppler Effect" or "Doppler Shift". Look it up in the > > encyclopedia or > > a fundamental of physics textbook. > > > > Think of when a fire engine drives by, recall how it seems to have a higher > > pitch when approaching then a lower pitch after it passes and is going away. > > > > -Dave > > > > "M. Adam Davis" on 04/07/2000 07:43:06 AM > > > > Please respond to pic microcontroller discussion list > > > > To: PICLIST@MITVMA.MIT.EDU > > cc: (bcc: David E Arnold/SYBASE) > > Subject: Re: Headphones changing pitch automagically [OT] > > > > Well, the act of moving the headphones away from you would cause a drop in > > pitch, but it would normallize once the headphones stopped moving away from > > you. The pitch would rise while you bring the headphones towards you, but again > > the pitch would normalize when they stopped moving (relative to your head). > > The faster you move them, the higher (or lower) the pitch goes. > > > > If the change does not follow this description, then you might be looking at the > > inability for the headphones to send higher pitched notes very far, so they > > become less-audible the further the headphones are away from you. This would > > make the spectrum of the music sound lower, and you might percieve that the > > pitches shifted instead of the top ones disappearing. > > > > Or your psycho. Perhaps to gov't is beaming info into your head to make you > > crazy. You should try wearing an aluminum helmet (except in thunderstorms!). > > > > -Adam > > > > I respect faith, but doubt is what gives you an education. -- Wilson Mizner > > > > Rich Leggitt wrote: > > > > > > So I'm building this MP3 player, and I'm listening to the music through > > > headphones. > > > > > > Then I take the headphones off and hold them away so that I can still > > > faintly hear the music. And the strangest thing -- there's a very dramatic > > > drop in apparent musical pitch. I put the headphones back on, and the > > > pitch goes back up. I take them off again and the pitch goes down again. > > > > > > Now, I don't think the frequency is actually changing (unless perhaps the > > > bulb in the refrigerator is also staying on.) > > > > > > But I'm wondering what's going on? Is this a known phenomenon, i.e. large > > > changes in apparent amplitude and/or apparent bandwidth translated by some > > > psycho-acoustic process into changes in apparent frequency? > > > > > > Or perhaps I AM the psycho in 'psycho-acoustic'? :) > > > > > > -- Rich >** --------- End Original Message ----------- ** > Download NeoPlanet at http://www.neoplanet.com