What do people think about the frequency response? I know cards drop off at the low end but this doesn't seem too bad (esp on-axis). How does this compare to larger and more expensive card mics?
That response is noted as being measured at 8", which is appropriate for the intended use of this microphone, yet is well within the 'proximity effect' zone where the low end response is boosted. Expect far more limited bass response than shown there at mic'ing distances greater than 3'. Those are very minimal, highly smoothed response graphs and only a single idealized polar. Doesn't really indicate a whole lot.
Also has a detachable connector.....??
Looks like a miniature coaxial connector which may be interchangable with DPA microdots?
Doesn't say what power required or permissible, but can be bought with XLR ($675 ea.) or pig-tailed ($570 ea.)
Presumably a low voltage powered mic similar to the B3/B6. Phantom power XLR adapter.
Pricey. In that range I'd look at the DPA 4098H ($500 with XLR adapter). It's slightly longer, but designed for choir mic'ing at a greater distance and probably has better though still limited bass response and an odd form factor that may or may not work for you. It has better documented response and polars at least.
[edit- self-noise figures are quite high]