Hello
I had a chance to buy two pairs of Stax ESTA 4u speakers.
Both pairs look nice, but all four had imbalance issue and I decided to check what is inside and if I can repair them.
As you can see, drivers are easy to open. The disintegrated foam's particles got into drivers and stick to the diaphragm (foam was layered with some glue).
I had to clean it all from this and use Licron on diaphragms (I did that only with one pair atm).
Now the one pair works well, bas is not so strong, but it is enough to work with some active sub.
The stereo sweet spot is really thin, but when you seat in the right place the image is sharp and precise.
I'm thinking about rebuilding the second pair, but to use drivers to make custom speakers, rather tall, just to use it as computer speakers.
Naked driver.