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History of headphones - a good article - Page 2

post #16 of 21

Do these companies have patents filed as to who was first or is it who is first to market is the winner?  

post #17 of 21
Quote:
Originally Posted by obobskivich View Post


Electrets have a permanent charge - electrostats do not (and rely on an external bias supply). They are similar but different. The HD 800 comparison isn't really related imho (ring radiators are a type of dome driver, and while they have different radiation and performance characteristics than conventional cones, they are still very much dynamic transducers).
More info:
http://en.wikipedia.org/wiki/Headphones#Electret
Sennheiser claims the Unipolar 2000 was the first open-back Electret headphone on the market. I believe Audio-Technica (and perhaps STAX) released models around the same time period, and just like the invention of the electrostatic headphone, there are competing claims to who got there first. redface.gif

 

The description on the wiki page for an electrostat is along these lines (if I got it right): charge on diaphragm, charge (audio signal) on metal plates that surround the diaphragm. The (covert) description on that page for an electret is the exact same: charge on diaphragm, charge on metal plates around the diaphragm. So electrets and electrostats operate on the very same principle, only differing in where the diaphragm charge comes from.

 

(But if one is to make a distinction that electrets aren't electrostats, they should maybe also start worrying about which amp an electrostat gets its charge from - whether they can be classed as true electrostats or not depending on the quality of the amp, since to me this dichotomy at its base seems a question of prestige, people wanting to separate cheaper electrets from the more expensive regular electrostats.)

 

I think you're right about the Unipolar claimed as being the first open electrets.


Edited by vid - 9/29/12 at 9:41am
post #18 of 21
Quote:
Originally Posted by Nectar View Post

Do these companies have patents filed as to who was first or is it who is first to market is the winner?  

In different countries and for unique inventions - emgm Koss in the US and Sennheiser in Germany. They own their own tech for sure. But its like MartinLogan and Quad - both make stats but both hold unique related patents. Very confused issue.
Quote:
Originally Posted by vid View Post

The description on the wiki page for an electrostat is along these lines (if I got it right): charge on diaphragm, charge (audio signal) on metal plates that surround the diaphragm. The (covert) description on that page for an electret is the exact same: charge on diaphragm, charge on metal plates around the diaphragm. So electrets and electrostats operate on the very same principle, only differing in where the diaphragm charge comes from.

(But if one is to make a distinction that electrets aren't electrostats, they should maybe also start worrying about which amp an electrostat gets its charge from - whether they can be classed as true electrostats or not depending on the quality of the amp, since to me this dichotomy at its base seems a question of prestige, people wanting to separate cheaper electrets from the more expensive regular electrostats.)

I think you're right about the Unipolar claimed as being the first open electrets.

I don't see it as prestige; its just different operating modalities. They are separate albeit similar tech - even the manufacturers point this difference out. The biggest advantage of electrets in theory is being able to drive from "normal" amps (Look at the Rotel as an excample). I think the quality concerns are inflated - consider that electrets "died" in the 1980s - stats from that era aren't world-beaters either.

While the basic operating principle is similar, its like saying an isodynamic is a dynamic because it uses magnets - it grossly oversimplifies the discussion.
post #19 of 21
Quote:
Originally Posted by obobskivich View Post

I don't see it as prestige; its just different operating modalities. They are separate albeit similar tech - even the manufacturers point this difference out. The biggest advantage of electrets in theory is being able to drive from "normal" amps (Look at the Rotel as an excample). I think the quality concerns are inflated - consider that electrets "died" in the 1980s - stats from that era aren't world-beaters either.
While the basic operating principle is similar, its like saying an isodynamic is a dynamic because it uses magnets - it grossly oversimplifies the discussion.

 

Though what's the difference in operating principle between regular electrostats and electrets - other than where the diaphragm gets its charge - which sets them apart so that it can be said that electrets aren't electrostats at all?

post #20 of 21
Quote:
Originally Posted by vid View Post

Though what's the difference in operating principle between regular electrostats and electrets - other than where the diaphragm gets its charge - which sets them apart so that it can be said that electrets aren't electrostats at all?

The diaphragm is permanently charged, it isn't receiving a bias supply from an amplifier or step-up transformer (which is what makes the distinction - whether or not the diaphragm is permanently charged or externally biased). They are very similar, but not the same thing. I really don't see why it's such an issue that they're distinct from other designs.
Edited by obobskivich - 9/29/12 at 10:20pm
post #21 of 21
Quote:
Originally Posted by obobskivich View Post

The diaphragm is permanently charged, it isn't receiving a bias supply from an amplifier or step-up transformer (which is what makes the distinction - whether or not the diaphragm is permanently charged or externally biased). They are very similar, but not the same thing. I really don't see why it's such an issue that they're distinct from other designs.

 

To me it seems that the electrostatic principle is like this: a charged diaphragm responding to charged plates around it. Whether the charge comes from the factory or through a wire to me seems a question of subtype - electrostatic being the umbrella term.

 

And I do think this is a semantic issue then, because you agree that electrets and electrostats are similar but not the same; the Stax SR-009 and SR-007 are similar but not the same as well. It seems that you assign the name electrostat to those electrostatic headphones where the diaphragm is charged via the amp - but why so? What if I were to call electrets electret electrostats (as they have been) and regular electrostats needy electrostats - would they seem as different then as they do when called electrets and electrostats?

 

One can of course always hit the dictionaries for the term electrostatic as well.

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