What should I use to transfer bigger files (audio files<=1GB) wirelessly (from an SD card) using an Arduino Nano? The range would be 7-10m through 2 walls.
For bluetooth I'd like to make a mobile app to pull files to the phone or a regular PC, for the nrf part, I'd make a receiver with an SD card on it and another NRF24 module.
What's the speed and power usage between the two, since the one sending the file will be battery powered?
The NRF24 maximum payload size is 32 bytes
That may influence your decision
How many hours are you prepared for the transfer of a 1Gbyte file to take ?
10 hours.
So why not carry out some tests, so that can be sure that the HC05 or NRF24 will actually work at that distance through the walls in question ?
How transparent walls are to RF varies hugely depending on the type of wall............
Well depending on the tests suggested in post #5, it could take a fair bit longer than that, or not work at all.
Neither the HC05 or NRF24 have the 'long range' modes that might be needed.
Because I can only afford one of those at the time.
Walls are european walls; brick.
Get testing.
If you manage to get 500 Kbps on a 1 Gbyte file, it will take almost 5 hrs to transfer
So it's unrealistic to transfer it with either bt or nrf24 in that time frame?
Depends on the walls ..............................
What about the realistic speed without walls 2-3m away?
At 2-3M the NRF24 should work at its highest data rate of 2,000,000bps.
However the NRF24 is limited to 32byte packets, so with packet overheads and the need for a send and acknowledge process you might be lucky and get a achieved transfer rate of a bit more than 500,000bps.
7m through two brick walls is almost certainly beyond an HC-05, and I doubt getting close to the walls will help.
Some other bluetooth module then?
Perhaps explain the actual project, as in why you want to use Wireless to transfer very large audio files between a couple of Arduinos that are only 2m apart.
Easy to do on SD cards ......................
The modern day version of sneakernet 
Yea maybe, I do sense an XY issue here.
it will be in a very tall place so I can't really deal with SD cards. I plan on putting it up on a tree to record birds then send audio back down to my house.
So what device is recording the 'audio' ?