a question about buffer

Hello all,

Whilst I nderstand the basics of buffer, I could save a lot of time if someone could answer the following question:

What sounds can you place in a buffer?
Recorded sounds/sound files, wav. aiff. etc I understand

but can you create a buffer that is constantly updating (or creating other buffers for each instance)?

My insturment will play many sounds from a buffer object so If my instrument keeps changing the sounds to be played and It is set up to play sounds from a buffer is there an easy way to make this happen or can I only load sounds from a buffer that already exist?

Thanks for any and all help

Ali