Hey there, just wanted to share my experience with my ProMedia 5.1 Ultras.
Purchased back in 2004, they started making a horrible squealing noise a few weeks ago. A little research on this site pointed me to one of the BASH chips. I wiggled it around and sure enough the sound would come back, but only for a short time. Naturally, I wanted to get it repaired.
I called Klipsch, but apparently they don't service this system anymore, so I decided to attempt repair myself. After a bit more research, and a few e-mails and phone calls, I ended up at Harman Audio. They were one of the few places that actually stocked the HC1011 BASH Chip.
Once I received it, it was a relatively simple swap. The only soldering experience I have was from 2 years ago when I installed a mod chip in a Wii. Other than that, I have no experience soldering.
The system now works perfectly. Like new.
My concern is that these BASH chips will eventually be hard to find, and the person at the parts department didn't mention a "successor" to this chip that we could use in its place.