I don't want to discourage you but this project is huge:
- Bluetooth (not with simple commands but with a continuous stream of data (audio))
- Airplaiy compatibility
- Signal processing (the DSP part)
- I2S communication to a CODEC
- Analog amp to drive something
Well... This is HUGE! I suggest that you split it into parts. Especially when you say that you are learning and not sure what the DSP is doing.
What I suggest is splitting the work into modules.
First you design your amp with your selected chip. You play with it with a dummy sound source (basic microcontroller producing I2S signal like tones). Then, when you are happy with it, you go to a bluetooth module. Try to implement some bulk transfer and try to obtain the data throughput you will need for audio.
Then, you can think if you need to perform some signal processing that cannot be done on your microcontroller which would justify the DSP.
Then try to put everything together.
If you want to do everything at the same time here is what is likely to happen:
- It's never right the first time. (especially when you are learning) thus you will need to debug and solve issue in all parts. When everything is together and interconnected and interdependent, this is much more complicated to do.
- It's a so difficult project taken as a whole that it will end up in the graveyard of unfinished project...