Hi Pete,
By Neutral Sound I meant no big EQ spikes noticeable and reasonably true to what I expect my bass to sound like. All somewhat subjective I know but if you go to http://www.prodipe.co.uk/mics/2140-bl21-lanen-contrabass.html and click on Specifications there is a frequency response chart.
48V phantom power is often required for Condenser Mics - most mixing desks will provide this through the XLR cable, as will some computer audio interfaces (The Scarlet 2i2 and similar) and some double bass preamps. Failing that, Google "48v phantom power" and you should get some options for external power supplies that can be purchased.
I used the mic with a Zoom A3 preamp which provides 48v phantom power and is excellent, but unfortunately no longer in production, although available 2nd hand on ebay etc and well worth the hunt as it can be used to blend a mic and pickup together.
Thanks for the enquiry and hope this helps
John