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can somebody please explain how an "Orthodynamic" headphone works? - Page 2

post #16 of 24
2/7/11 at 1:47pm

I think the LCD2 driver is very similar to the T50RP, why reinventing the wheel.

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post #17 of 24
4/24/11 at 2:46am
Quote:
Originally Posted by MrGreen View Post

 

“In an orthodynamic driver, the diaphragm is a thin, light membrane whose entire surface is covered with a conductive coating whose ‘conductors’ are arranged in a specific pattern. The conductive driver membrane is in turn suspended near an array of magnets arranged so that, when an audio signal is fed to the driver, the entire diaphragm surface is alternately pulled toward or pushed away from the magnet array.



I'm still hassling to get to the gist of this, In stats the stators are electricly charged with everchanging polarity, How do the magnets achieve polarity so that the membrane would 'know' which way to go?

 

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post #18 of 24
4/24/11 at 6:20am
Quote:
Originally Posted by Amarphael View Post





I'm still hassling to get to the gist of this, In stats the stators are electricly charged with everchanging polarity, How do the magnets achieve polarity so that the membrane would 'know' which way to go?

 


Like in a dynamic headphone the magnets are permanent magnets and therefore provide the magnetic field. The diaphragm moves because the voice coil is embedded in it.
A dynamic headphone is actually very similar but here the voice coil is not embedded in the diaphragm and sits in a small air gap where magnetic flux density is very high.

Like InnerSpace mentioned it's a compromise like anything else. Theoretical benefits don't necessarily hold water in practice.
Edited by xnor - 4/24/11 at 6:38am
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post #19 of 24
4/24/11 at 6:55am
Quote:
Originally Posted by Amarphael View Post





I'm still hassling to get to the gist of this, In stats the stators are electricly charged with everchanging polarity, How do the magnets achieve polarity so that the membrane would 'know' which way to go?

 


It's basic physics that a current moving though a magnetic field creates a force, which in this case moves the diaphram.  In the case of dynamic headphones, it moves the magnet.

 

http://en.wikipedia.org/wiki/Magnetic_field#Force_on_moving_charges_and_current

 

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post #20 of 24
4/24/11 at 7:48am
Quote:
Originally Posted by scompton View Post




It's basic physics that a current moving though a magnetic field creates a force, which in this case moves the diaphram.  In the case of dynamic headphones, it moves the magnet.

 

http://en.wikipedia.org/wiki/Magnetic_field#Force_on_moving_charges_and_current

 


The magnets in dynamic headphones move? O_o I don't think so.
Edited by xnor - 4/24/11 at 7:49am
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post #21 of 24
4/24/11 at 8:12am

You're right, I typed that without thinking.

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post #22 of 24
4/25/11 at 11:54am

Thanks for clarifying guys, I didn;t think the magnets are permanent charges. So it is fair to assumethat since orthos  (the recent ones at least) have substantially larger magnets than conventional dynamics, thus achive greater magnetic flux correct? Is't this advantage also creats more EMI emission than regular dynamics?

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post #23 of 24
4/25/11 at 12:21pm

I'm not sure what the diameter of the magnets are, but I think it has more to do with materials than size.

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post #24 of 24
4/25/11 at 12:56pm
Quote:
Originally Posted by Amarphael View Post

Thanks for clarifying guys, I didn;t think the magnets are permanent charges. So it is fair to assumethat since orthos  (the recent ones at least) have substantially larger magnets than conventional dynamics, thus achive greater magnetic flux correct? Is't this advantage also creats more EMI emission than regular dynamics?


My guess would be that since the diaphragm needs some room to move between the magnets that the distance between them is bigger than the air gap in dynamic drivers. With increasing distance the magnetic field weakens (in the square!).
Regarding your second point, magnet size, the T50RP for example seems to use three bar magnets on each side that cover a big area so again I think that the magnetic flux isn't as concentrated as in a dynamic construction (but probably doesn't have to be because the diaphragm could be very light and the voice coil is spread over the same big area).

A simple way to compare the efficiency of those constructions is to take a look at the sensitivity (see specs and measurements). For example:
T50RP (50 ohm) = 98 dB

mdr-v6 (60 ohm) = 106 dB
HD600 (300 ohm) = 107 dB
all at 1 mW.

6 dB higher sensitivity means you only need a quarter of the power to reach the same output level.
Edited by xnor - 4/25/11 at 1:20pm
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