That article only makes reference to the old 208E Sigma, which
is not that great a driver compared to more recent Fostex
offerings. The current FE208Ez is what I would consider a
superb midrange. It is capable of doing bottom end like the
other 8 inch offerings in the category of high-efficiency / full
range but it does need a tweeter at about 10 KHz and above.
It is extremely efficient and has a pretty smooth response with
surprising clarity. At the top you will see some diffraction issues
which impart some directionality, but I consider it a great driver.