drop down ceiling in basement...??

Read Earl Geddes' Premium Home Theater.

http://www.gedlee.com/downloads/HT/Home_theater.pdf

http://https//forum.audiogon.com/discussions/subwoofer-with-zero-punch-help
My subwoofer is performing very poorly with a drop ceiling (it became a huge bass trap). Plus it rattles. I would strongly suggest against it.

Read Earl Geddes’ “Premium Home Theater.”  It’ll help you decide the best methods and materials for ceilings, walls, insulation, resilient channels, etc. 

Agreed. The suspended ceiling and false plenum will act as a resonator and sound board. I use open joists and sheetrock in my space in a basement.

Drop ceilings are not a great idea, unless you have tons of head room. Try to get as much height as you can. Dry wall or dry wall with exposed floor joists.  

If you are using in ceiling or in wall speakers, be advised that proper damping is required. Some of this may be included with the speakers you purchase. Ceiling tiles won't affect sound in the way you think, so that's a good thing. (in this particular case)