Forgive my ignorance as I have never used BFD before but I have the app (but not the core library) and there is an add-on of just cymbals that I would like to use but do I need to have the core library installed before I can use an addon ?

yeah its a stupid question but if I don't ask I wont know...

 

It seems that I am not going to learn by asking either... jezzzzz

 

does the installer ask for BFD3 Core Library location?

the only way to learn is testing, you 'll get the response faster. because everybody here use the complete version.

 

I 'm sure that you can install it and run it without the core library, and then install the expansion you 'd like.
BFD 3 is in my opinion the best choice for realistic recorded drums in vst format, try the Andy Johns expansion (kinda thin but you can mix them to have the right amount of low end) Vintage Recoring Technics expansion is realy great (dont be fooled by the "retro" in the name, its a great expansion for many genres), Modern Retro and Heavy expasnions are great too !!! And dont forget the chocolate audio Black Album Drums, ULTRA GREAT SNARES for rock , heavy rock and metal!!!
I ve tried every drum vst out there and every time i end up using bfd3. Have a great time making music buddy !

 

Yes, @Mister Grimm is right. I just tested it. The core library is handled like all expansions. You set the path yourself. I can disable every library (even the core library) in the BFD content manager. BFD starts without libraries and sound. I can activate only 1 expansion, BFD starts.