I contacted B&W about that today and, for myself, both good news and bad news.
First the bad: I bought my px8s off craigslist (from a reviewer, $500). I foolishly had neglected to first read the warranty info on the B&W site, and it clearly states I must have a receipt from an authorized dealer, or no warranty service. So, word to the wise, make certain that's in place if buying second-hand.
Now for the good news: I think I fixed it. The way the battery problem manifests is it will quickly go to 100% with a solid green light, and stop charging, then rapidly deplete when used, because it was a phantom charge. So, still smarting from a self-inflicted hard face-palm after the support call, I decided not to take 100% for an answer, and repeatedly pulled and pushed the charging cable back in until it showed the real percentage, 23% or something. I did this a few more times and it went up a couple of pct before jumping back to solid green . Long story short, I found that if I used them for a time, even just a few minutes, followed by a charge, they would work their way up a bit more before stopping solid green. Over the course of my work day I got them to over 90%, and since then they've been discharging normally at the 30 hour rate. Also, the diminished amplification problem went away shortly after I started this charging game. My hope is that I somehow reconditioned the battery it will be back to normal, but hey I can live with this! Gives me something to do during meetings.
