Electrostats and Dust

[Hipper]

Currently I use ribbon/cone box floorstanding speakers in my flat. This flat seems to be rather dusty. The dust is not a sonic issue as far as I can tell.

Reading about electrostats it seems dust can be an issue. Quad say in the manual for the ESL 2912 that loudspeakers are protected against the ingress of dust etc.. Periodic servicing is recommended at two year intervals to keep your speakers in pristine condition.

Sanders 10e manual says if the electrostatic panels are dusty, you may gently wipe them with a damp sponge. There's no mention of regular maintenance.

Martin Logan suggest vacuum cleaning or blowing three or four times a year.

Do users find dust an issue? Is covering the speakers when not in use a good idea, or is most of the dust captured because of the electric charges on the panels when in use so covering when not in use is pointless? Is regular servicing required as Quad say?

 

[RayDunzl]

I keep a black "body pillow" pillow case over my stats. Stretchy cotton jersey (like soft t-shirt material). It's just the right size to cover the panel.

Wash it every five years or so.

I don't remember ever cleaning the panels themselves.

Once in a while pull the cover up if somebody wants to look. I already looked.

MartinLogan reQuest - 22 years old now.

They have a music sense circuit to turn the static charge on and off. The charge leaks down after a few hours of being idle.

 

[Blumlein 88]

Quads have plastic sheeting around the panels or at least ESL63s did and I think the modern ones do as well. That pretty well protects them.

I've gently vacuumed the fabric covering of other brands I've owned. Acoustats, and Soundlabs. Though some do, I've never run mine naked.

I had ESL 63s something like 12 years. The Acoustats were used when I purchased them as were the Soundlabs. And no issue with dust on them either. Closest I've come is one panel would very slightly arc at very high volumes in a certain spot. It was a tuft of the covering fabric that had come loose inside. Gently moving it and vacuuming it out fixed it.

 

[Scgorg]

Generally dust in electrostatic loudspeakers is not an issue, for headphones it can be. When there is dust that makes the diaphragm discharge at the stator it will generally be a very localized discharge due to the high resistance of the diaphragm coating. For loudspeakers these discharges should be inaudible or almost inaudible in most cases, as the diaphragm as a whole still retains its charge, and the discharge sound should be low in level. A good example of how the diaphragm holds its charge can be achieved by disconnecting the diaphragm bias but still supplying the AC signal to the stators, the loudspeaker will still play for a while before fading out.

For electrostatic headphones the problem is somewhat larger, as it is much closer to the ear, so the relative SPL of any discharge is much higher. For this reason almost all electrostatic headphones use thin film dust covers (typically in the range of 1-2 micron) in front of both stators. For electrostatic loudspeakers other solutions also exist, such as the ceramic stator coating on the Sanders 10e. To conclude: dust can be an issue, but probably not for you as the end user. The engineers behind the loudspeakers should already have made efforts to minimize the effects of dust.