where are sounds/samples in logic x

Where are the sounds and samples for Logic stored by default?

More importantly, how can i change that? -- i hope, by default.

I want to always keep my sounds on an external disk, actually internal disk partition. Every time i download some update or more sounds, they go to the startup disk, which quickly becomes full.

I have Garageband too, and i imagine that they share sounds and have the same issue.

Thanks all.

P