A:

You can load data into IOP or SPU memory using the RAD_IOPQueueAsyncReadAtTop function with the proper destination pointer type.

Then, to use this data later, you can either copy it into EE memory using the same RAD_IOPQueueAsyncReadAtTop function, or, more convienently, you can simply stream the digital audio directly out of these other memory banks using the AIL_open_stream function.