Dynaudio (Evoke) + ExpertPro 220

[David A]

Possibly @Jean-Marie is referring the cross-over?

That's what I wondered, and why I asked, but the problem with that if what SAM is primarily designed to do is to correct phase errors then a speaker which has had its bass phase response corrected by the crossover has no need of SAM. There is one other problem and that is that I have never seen a test report for a speaker that has perfect phase response in the bass.

If @Jean-Marie was referring to the crossover he would be correct, you would expect to see no difference between SAM off and SAM at 0% if phase correction is the only thing happening at 0% and that's what Devialet's statements suggest but @Delija has Dynaudios and @jvoki has Magicos and the test reports I have seen for  several models of speaker from both manufacturers have always shown phase errors at low bass frequencies so neither of those speakers is going to fall into Jean Marie's "Speaker A" group hence we should expect to find a difference between SAM off and SAM on at 0% in their test results.

I cannot think of a speaker with a cone bass driver that does not have phase errors below 150 Hz. If there is a speaker that does not have phase errors in that area then it probably doesn't have a cone woofer so it's will use something like  a ribbon or electrostatic panel (only other bass driver technologies I can think of) and Devialet say they can't make SAM profiles for those types of drivers so we would not be able to test their performance with SAM.