MI> Gordon has corrected me: only about 6 feet tall.  In any case, I 
 MI> believe (it's been a while since I looked) that they are comprised of 
 MI> only the ribbon driver, and a (relatively small) woofer (one may want 
 MI> to add a subwoofer to extend the lows).  That's one of the 
 MI> (theoretical) advantages of ribbon speakers: the extremely light 
 MI> elements reproduce highs very well, while the sheer size of the moving 
 MI> surface extends the lows quite well.
 MI> Of course, there are always trade-offs.  A near-ideal design for 
 MI> reporoducing sound, but 
 MI> they must be extremely large, the ribbons are relatively very fragile, 
 MI> they're hugely 
 MI> inefficient, and being an entirely capacitive load, require an amp that 
 MI> can deliver 
 MI> *LOTS* of current.
The load is purely resistive, unlike dynamic drivers which have reactive
elements which do require current as you describe.   It is
electrostatics which are largely capacitive.  The stable non-frequency
dependent load of a ribbon is another mark on the positive side of the
list.  Ribbon drivers need not be low in efficiency.   The Carver 60"
long version is 90 db with an active xover.  This is probably a bit
over the average for all types of drivers.  The foil on diaphragm
versions, like the Carvers, can have multiple turns of ribbon in the
gap.   The non-diaphragm versions usually have one turn in the gap and
are inefficient.  The Carver drivers are extremely durable compared to
other kinds of drivers.   With the ribbon in air, the thermal limits
are very high.   It is said to take 500 watts with no difficulty.  The
diaphragm is made of a very stable material which does not change
dimensions with temperature.
--- Via Silver Xpress V4.3 SW11977
---------------