What external memory I should get for my MIDI project?

I am fully new into Arduino, so hopefully my questions make sense. I read quite a bit last day about it, but I am uncertain about what I need or if I miss some solutions.

What I need is: - Store minimum 32 KB, which is retained when the power is off - I need low MIDI latency, like 15 ms and reading on various places within those 32 KB, performing some calculations (no rocket science) and send like 5-100 bytes through MIDI. - One midi in, one midi out (maybe one midi through) - Later possibly DMX (for controlling light)

What I think I need is: - Arduino Mega (because I have read the MIDI and DMX all need their own UART and I also might need EEPROM/SRAM using RX/TX). - EEPROM to store the 32 KB and retained while power is off; the Mega does not have enough - SRAM to load the EEPROM 32 KB and add some calculation result or structure the 32 (condensed?) KB into an easier form to use

Questions: - Do I really need the Mega (because of the 4 UARTs) or will an Uno be enough? - Is EEPROM the best solution and what type is best/easiest to use? - Is SRAM the best solution and what type is best/easiest to use?

I also thought about SD storage instead of EEProm, maybe that works too. If I read the 32 KB I don't need the EEPROM/SD storage anymore, unless SRAM is expensive, but if I have to reread the EEPROM or SD it might affect the latency.

Kind regards,

Michel Keijzers

small ? http://www.ti.com/lit/ml/szzt014a/szzt014a.pdf (U'll find faster Arduinos)