Dennis, I recently bought the B652's and my ears agree with your first plot. The tweeters almost seem as if they're not hooked up. Your plot shows that the output drops like a rock above 5kHz. Either PE substituted the old tweeter for a newer cheaper (arguably non-working) tweeter or it is hooked up out-of-phase or the 3.3uF cap in series the driver is somehow not properly passing the highs. I'm very tempted to return the B652s. Zaph and others provided freq response plots that seemed reasonable for a cheap speaker, but with a tweeeter installed, the plot that exhibits highs that are completely gone is just wrong. Zaph took measurements many yrs ago, so it is quite possible PE subbed the tweet out. Granted I paid only $30 for the pair, but I bought them based on Zaph's results and simple mod that he said made it a passable sounding speaker. While I havent added a xo yet, I'm finding it hard to believe these speakers can sound halfway decent.
I'm wondering if you or Chu can take measurements with (1) the tweeter phase reversed and (2) the tweeter disconnected. I'm having a hard time believing that the tweet is wired wrong but it is weird that you show such a dramatic null at 9kHz. I'm wondering if anyone out there has both the "old" (2009) and "new" (2012) model, and would care to comment.