can somebody please explain how an "Orthodynamic" headphone works?

Magnets.

“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. In theory, the benefits of this approach are twofold. First, the diaphragm can be very light and responsive (lighter than the voice coil/diaphragm assembly of a traditional dynamic driver). Second, driving forces act over the entire working surface of the diaphragm, potentially offering more precise control with greater freedom from unintended resonance or vibration.”

They need power because large magnets and they're inefficient. Not all of them do (myth)

Quote:

Originally Posted by scannon18 

Wow, that's a very interesting way to make a headphone.  I can see why it'd be inefficient, but I can also see how it would make one hell of a headphone.

Wait until you actually *hear* an ortho. My guess is that its going to take you by surprise if you have spent most of your life listening to conventional dynamic headphones.

How do these compare with electrostatic headphones? Don't electrostats also use a thin membrane, but electrically-charged rather than magnet-based?

Quote:

Originally Posted by scannon18 

Wow, that's a very interesting way to make a headphone.  I can see why it'd be inefficient, but I can also see how it would make one hell of a headphone.

It's a compromise, like anything else.  Main disadvantages are having two heavy iron disks prone to ringing and resonance, and having to listen through a matrix of small holes in said disks.

Quote:

Originally Posted by infinitesymphony 

How do these compare with electrostatic headphones? Don't electrostats also use a thin membrane, but electrically-charged rather than magnet-based?

Stats follow the same three-layer sandwich arrangement, but the diaphragm has no voice coil - it carries a constant electrostatic charge.  The audio signal rides on the outer layers (the stators.)  Advantages are a super-light and responsive diaphragm, and a skeletal construction for the stators (often just fine wire grids.)  Disadvantages are the requirement for very high voltages (requires a special amp, or in-line transformers, or both) and limited excursion, because the gaps are very tiny.

Makes sense to me. Thanks for the informative and concise explanation.

Quote:

Originally Posted by estreeter 

Quote:

Originally Posted by scannon18 

Wow, that's a very interesting way to make a headphone.  I can see why it'd be inefficient, but I can also see how it would make one hell of a headphone.

Wait until you actually *hear* an ortho. My guess is that its going to take you by surprise if you have spent most of your life listening to conventional dynamic headphones.

Just like any headphone, they aren't for everyone.  I definitely prefer dynamic to orthodynamic.

Has anyone here compared planar magnetic driver to conventional moving coil driver speakers, as well as planar magnetic (orthodynamic is just a marketing term) headphones to moving coil headphones?

I'd be interested in how they compare, generally speaking.  I like planar driver speakers, but I've never had the opportunity to hear planar headphones.

I just have to say, Mr. Green, that that was *the* perfect, spot-on response to the poster's question....If only every post begat such an initial response, complete with detailed diagrams!

Quote:

Originally Posted by mijbil 

I just have to say, Mr. Green, that that was *the* perfect, spot-on response to the poster's question....If only every post begat such an initial response, complete with detailed diagrams!

Copy+paste works wonders.

yeah, but this is a vintage Yam' ortho...who does what in a T50RP exactly? strong magnets(133dB SPL max) on both sides, a copper diaphragm in between...and that's it? it's all explained here: http://www.fostexinternational.com/docs/downloads/pdfs/RP_Headphones_Brochure.pdf

how can this thing sound so good? and sell for so cheap?

magic and magnets, ;p

the fostex design is more simple than the one shown because the magnets are just rectangular blocks and do not require much if any machining to make (unlike circular magnets with square holes in them), also the membrane is just very very tiny printed circuitry (or more likely photoresist) which is very very cheap, the housing is, well, plastic like abs, the padding is minimal. the designs are very different but the principle is the same. 

fostex has figured out how to make a very simple design sound as good or better than more expensive, but older, ones. (I believe it is due the small size and pattern of the circuitry). they really are amazing drivers for the price.

the lcd2 probably has a design that is more similar to the one shown (circular rather than square) because it is a better design, but more expensive to make. I would love to see pics of one torn apart