How to test the quality of the conductive membrane?

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Well-known member
Apr 7, 2005
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Central Sweden
Have you ever gone up close to the stators to find out where the sound is coming from? Of course we all have, and what more is we sometimes discover that the SOUND is not equal across the panel. Well it should be on new speakers, but after XX amount of years the sound can start to decline in various areas. The smaller bands towards to top of the speaker can be quite faint if not entirely silent and the bass can seem somewhat domineering from the sides and the bottom area.

In the past it has been critical for me to know that my speakers are performing at their best. What good is it to me pondering over components needing to be upgraded or speakers moved if they are loosing a few decibels in the highs and additional gain from the amp is required to reach that all time earth shattering volume.

Well here’s a simple test that should put your mind at rest and first of all I should remind anyone attempting this they are doing it at their own risk. We are dealing with the static charge trapped between the 2 HV stators and if you don’t feel comfortable doing this please don’t. Any flaws in the insulation on the stators can yield a spark.

What we are attempting to do is transfer some of the static charge from one area of the speaker to another. When we do this we are in essence proving that the less sounding area still can hold a static charge and that there could be a static leak or static discharge somewhere.

Take a standard RCA cord and hold the center pin through one of the small holes at the base of the stator against the membrane (the center pin should have a smooth surface). Now take the other end of the RCA cord and place the center of that plug against any weak sounding part of the membrane (try to avoid resting the center pin on the stator). Needless to say you should have music playing when doing this. If the sound returns to that area of the panel then you know that there could be a drain on the static charge somewhere.

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