Flat Anechoic Measured Frequency Response Speakers

It's amazing to see that some of my favorite speakers tend to have similar frequency response: Dynaudio and Thiel. The impedeance plot is very helpful in matching amp.

Coincident speaker definitely is very friendly toward SET amp while Thiel and Dynaudio will rquire lots of low impedance driving capability.

Shadorne,

The ATC has a very flat response. Do you find that flat responses sometimes limit the 3rd dimension to the soundstage? In other words, do you find it is more like a two dimensional picture than a three dimensional picture depth-wise?

Thanks.

Looking at the measurements for several speakers I know well, it surprises me how similar many of them are. For example, Dynaudio C1 and Thiel 2.4 look quite similar (and both very flat) to my uneducated eye, although they don't sound the same. Interesting to look at something like the Reference 3a MM decapo, which seems to measure pretty horribly. Or the Silverline Sonatina, which has a big midrange dip. Even the Watt/Puppy is a bit ragged. How important is this, I wonder.

Would love to see measurements for some models of Harbeth.