High BL drivers.

[Acoustic Absorb]

I read an interesting article at http://www.aes.org/sections/uk/meetings/0403.html about high BL drivers using very powerful magnets. It seems it is possible to achieve low frequency response from very small enclosures using these drivers.

Some questions spring to mind from reading Mr. Vanderkooy's extract:
Is it true that because a very small enclosure is used the Fc must be increased so the driver is operated mostly below resonance ?

It seems to me that the 'cost' of getting bass from a small enclosure using high BL drivers is an amp capable of high voltage swing to overcome the back emf of the driver, and an eq circuit to flatten the response. While it is not a free lunch, it seems like a gourmet lunch for the price of a take away.

Are there other drawbacks?

I would be interedsted in opinions on this subject. Has anyone built one?