Monsoon drivers?

[Capn Haddock]

I have just stumbled across four apparently identical "Level 9 Sound Designs, Inc" drivers. They appear to be magnetic planar drivers, but I don't know how to use them without specs, specifically the low pass crossover point. How low can they go?
The info off the driver reads: "PFT-150-4"
Can anyone help me with specs? I would like to use these drivers to build a set of PC surround speakers, and would appreciate any guidance I could get.
Thanks!

 

[tubesaregood]

http://www.anandtech.com/multimedia/showdoc.aspx?i=1108.

250 Hz.

 

[Capn Haddock]

Thanks for the info and link. I'm sure that's a reasonable hi-pass point, but I may push it up to 300hz or so to be sure.
The drivers I have actually appear to be a bit different than the the ones pictured in the link. I'd include a picture, but the 100K limitation on file size won't allow me to post anything with useful detail.
Thanks again.