My bad The graph on my site is of the earlier version with the offset tweeter and mid. We switched to in-line drivers when we ordered the prefab cabinets because we didn't want to risk having the factory mess up some pairs with the same offset--not mirror imaged. The even spacing of the tweet and mid make for a very small diffraction peak around 30-40 degrees of faxis. I engineered in a little dip on axis because it sounded a tiny bit better due to a more even power response. The little bump in the highs is just a feature of the RAAL that isn't worth throwing components at. I think it sounds better that way. Although the common wisdom is that ribbon tweeters can sound harsh, quite the opposite is true, at least for the RAALs. Also, the bump is also centered around 10 kHz, not 7 kHz, which is even less of an issue. A little bit of a bump doesn't have any negative effect that I can hear, and frankly I prefer it. Virtually all of the recent BMR's I've measured have had it. If you look at the listening window response in the review, it fits within a 2 dB (+/ 1 db) window over virtually all of the frequency range. That's good enough for me.
