Why so many used focals?

@rlovendale 

That's exactly what McIntosh amps are designed to do with the autoformer regardless of the load characteristics. That's why you aren't going to get the best sound from Focal using their amps. Let me try to explain it...

With a typical direct coupled voltage source amp the goal of the amp is to just drive the voltage into the load regardless of impedance. If the impedance is high, it just pushes the voltage with less current. If it's low, more current. That's not what McIntosh amps do. 

McIntosh autoformers are designed to maintain constant power regardless of load. When it sees a high impedance, it doesn't just maintain the voltage and let the current float. It will drive try to drive the same level of energy, both voltage and current, into that higher impedance load. The same for low impedance loads. 

The problem is that Focal designs their speakers to be powered by a voltage source that lets the current float around a bit. Focal uses low impedance through the bass region to get the better bass response by letting the amp drive more current into the speaker. Beryllium tewwters cover a wide range and as a result swing from 8 ohm up to 20 with phase angles that swing downward. You see that bump in their response at about 10KHz because that's where the phase angle is about 0 degrees and the impedance is pretty benign. You're getting good energy transfer, plus that where 1 inch tweeters begin to become very directional. If you're driving it with an amp that only seeks to achieve flat output power, you're going to get overwrought highs as the impedance rises sharply past 10KHz and the phase angle goes more negative. The speakers is expecting to get less power in the form of less current. That's what it's trying to tell an amp that's acting like a voltage source. But that's not what autoformers do. 

The thread started when I started to research focal speakers from owners by checking forums and in comparison to other big players there wasn’t much activity . for example Dynaudio has 10,000 posts on a forum that focal has 1,000 then looking on the used market for price comparisons there’s as many or more focal speakers for sale....soo if, and this is really not science, but if there’s 10 to 1 active on the forums is it wrong to expect a comparative amount of trade volume? I’m sure there’s many reasons that have nothing to do with quality. Many people go online only when somethings wrong and that interpretation would suggest focal customers are more satisfied and upgrade within the same brand or are dealer promo's. there’s any number of ways to interpret the observation that have nothing to do with bashing the speakers I was seriously considering to be my LAST speaker purchase. Since finding these Usher BE20-DMD dancers i'm tapping the brakes on changing anything.

I'd say there are lots of brands that are disproportionately represented in forum chatter. Take Tekton for example. They Dell a tiny fraction of what many others do, but their costumers are absolute fanatics on forums. 

kosst, you bring up some great points in your post but what you describe regarding the speakers’ impedance variations (as a function of frequency) is nothing unique to Focals. With a very few exceptions, majority of the cone driven speakers have similar behavior and many sound pretty good when paired with McIntosh Autoformers. It mostly comes down to the listener preference. In general, I think more efficient/sensitive speakers with higher and more stable impedance tend to be less picky about the pairing amplifier in most systems/rooms.

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.