How do electrostats work?
Jul 5, 2008 at 11:56 PM Thread Starter Post #1 of 15

TheMarchingMule

Headphoneus Supremus
Joined
Feb 1, 2006
Posts
9,158
Likes
20
Location
SoCal
I remember there being a thread awhile ago that had .gif images of how an electrostat headphone/speaker worked compared to a dynamic headphone/speaker. The OP post was really long and explained a ton of detail, IIRC. I think it was Duggeh who did it, but I'm not quite sure anymore.

Thanks in advance to whoever finds the topic or is able to re-explain it here!
biggrin.gif
 
Jul 6, 2008 at 12:30 AM Post #5 of 15

TheMarchingMule

Headphoneus Supremus
Joined
Feb 1, 2006
Posts
9,158
Likes
20
Location
SoCal
@Faust2D: Perfect! Thank you!
biggrin.gif


@Uncle Erik: Sweet, I'll check that out next.

@spritzer: My bad, I have a bad headache right now, so I can't think of the obvious right now.
 
Jul 6, 2008 at 1:07 AM Post #6 of 15

Uncle Erik

Uncle Exotic
Joined
Mar 18, 2006
Posts
22,597
Likes
501
If you want more info, check out the books by Wagner and Sanders:

Old Colony Sound Lab -

Those will guide you through the theory and even building a pair. Though I'm partial to Verhagen's ribbon book there - I built a pair a few years back and still get a lot of use from them.
 
Jul 6, 2008 at 1:14 AM Post #7 of 15

synaesthetic

Headphoneus Supremus
Joined
Mar 5, 2008
Posts
2,263
Likes
11
How difficult is it to build a pair of electrostatic headphones? Looking at the theory of operation and the construction, it doesn't seem very difficult. The design looks incredibly simple.
 
Jul 6, 2008 at 1:22 AM Post #8 of 15

ak40ozKevin

100+ Head-Fier
Joined
Apr 4, 2007
Posts
345
Likes
0
Seems easy enough to make a basic electrostatic headphone.

HeadWize - Project: DIY Electrostatic Headphones by Andrew Radford

Here's a pretty good guide which helped me better understand how they work. While this guide doesn't necessarily build a high quality headphone it shows you how it can be done.

I've also seen a few sites dedicated to DIY speakers and they have different thicknesses of the mylar film and some other components available to order.
 
Jul 6, 2008 at 1:55 AM Post #9 of 15

BigEat

500+ Head-Fier
Joined
Sep 26, 2007
Posts
606
Likes
10
We used to work on projects with electrostatics all the time when I was in engineering grad school. Basically, it's like playing with two magnets with a "diaphragm" between the magnets. Instead of magnets, the speakers or headphones in this case use "stators", which is a fancy term for the transparent grilles. The grilles are electrically conductive material, but typically acoustically "inert" as well. Thus, the stators are conductors but don't color the sound acoustically. Between the stators is inserted a material used as the diaphragm. In school we used all sorts of material but I suspect the typical source is Mylar, very rigid, durable etc.

The stators are enabled with current conducting materials throughut, usually copper, but not always especially in headphones as I understand it. The amplifier simply delivers voltage to the stators and the diaphragm. This creates an electromagnetic environment where there are positive and negative charges just like a magnet. The positive charges repel one another just like sticking common ends of a magnet together while the negative and positive attract one another.

A signal passing through the amplifier creates a positive voltage on one stator and a negative voltage on the other stator. Then, the voltages alternate back and forth between positive and negative but at ultra high speed of course.

This sound is prouced by the following. At one instant, the front stator will be positive while the back is negative. The diaphragm's polarity does not change and remains static. If the diaphragm is negative it will be attracted to the positive stator and repelled simultaneously from the negative stator. Remember, the diaphragm does not change polarity like the stators.

The amplifier poduces current in costantly reversing polarity. The constantly reversal of the stators polarity changes the polarity of the stators which in turn causes the diaphragm to move the opposite of the way it moved in the prior signal impulse. This "oscillation" of course happens very, very quickly and produces air pressure waives through the movement of the diaphragm, just like any speaker or headphone. The ear perceives the waves as sound or music.
 
Jul 6, 2008 at 2:09 AM Post #12 of 15

BigEat

500+ Head-Fier
Joined
Sep 26, 2007
Posts
606
Likes
10
NP my man. We screwed it up enough times; I couldn't build one, but I generally know how it's supposed to work.
 
Jul 6, 2008 at 2:10 AM Post #13 of 15

synaesthetic

Headphoneus Supremus
Joined
Mar 5, 2008
Posts
2,263
Likes
11
I wish. That's my end goal. Once I have those I'm officially done, I win Head-Fi, see the credits roll, uninstall and put the discs away.
 
Jul 6, 2008 at 5:07 AM Post #14 of 15

krmathis

Head-Fi's Most Prolific Poster
Joined
Jan 13, 2004
Posts
34,764
Likes
74
They do work very well, thank you!
smily_headphones1.gif


Seriously. The Wikipedia page 'Uncle Erik' linked to are quite explaining.
The SR-Lambda Pro have not arrived in the US yet, so you still have some time to read up on the subject.
 
Jul 6, 2008 at 9:53 AM Post #15 of 15

spritzer

Member of the Trade: Mjölnir Audio
Joined
Aug 22, 2002
Posts
10,055
Likes
128
Quote:

Originally Posted by synaesthetic /img/forum/go_quote.gif
How difficult is it to build a pair of electrostatic headphones? Looking at the theory of operation and the construction, it doesn't seem very difficult. The design looks incredibly simple.


The drivers look simple but they are anything but that as the devil is in the details. I can make a set of drivers in about an hour from scrap materials found around the house and they will play but to reach something like a Lambda or SR-007 requires serious knowledge and experience. Every last part of the drivers plays a crucial role and understanding how all these factors and compromises work together is the key. When somebody does get it right you end up with a legendary product like the Stax SR-1 and Quad ESL which are still great after 50 years.
 

Users who are viewing this thread

Top