Glancing over various measurements for Bowers and Wilkins, DeVore, Wilson, Harbeth, GoldenEar, and KEF, many had various lumps and bumps in their impedance, Wilson being among the flattest and B&W often going clean off the graph past 20 ohm. Generally though, the group didn't see big lumps in their tweeter regions. My Focal 936's would fall into the group too. The big lump Focal Be tweeters exhibit is at least somewhat unique based on my randomly pulliing measurements out of a hat.
So, while a McIntosh amp would probably play well with most of the speakers who's measurements I glanced at, justifying their philosophy on autoformers, speakers with those Be tweeters might not be a good match. Not so sure about those off the chart upper mid-range lumps some B&W make either.
So, while a McIntosh amp would probably play well with most of the speakers who's measurements I glanced at, justifying their philosophy on autoformers, speakers with those Be tweeters might not be a good match. Not so sure about those off the chart upper mid-range lumps some B&W make either.

