Contact Gershman, they have excellent customer support. 

BTW, 50% of the preamp dial means nothing.  Depending on the source, at 50% of the volume dial you could be driving your amp to full power.

Will do and agreed, they’ve been very helpful in the past.  Not sure I agree on your assessment.  50% volume might be driving the output to 70% power, but don’t believe it’s possible that it could be 100% at 12 o’clock.  Amp should clip way before full power output.  

This failure likely reflects more on your amp than your speaker. 

You can also check your crossover. the fact that 2 drivers are misbehaving might point to the crossover, which would be much easier to find parts to rebuild.

Jerry

Jerry,

thanks for writing.  Curious what makes you say that regarding the reflection on the amplifier?  This amplifier

was recommended to me by Gershman, a Simaudio 340i.  It’s very capable.  
 

how does one check the crossovers?

I can really to help you to find and replacing maching woofers, located in Brooklyn

https://bacheaudio.com/