Just a quick update, I've been thinking about how to do the main FFT transformations, I need to do 2 FFT and 2 Inverse FFT calculations at the same time. To me, this immediately shouts FPGA, so I am currently researching the best chip to use. I'm thinking I could also produce a small tutorial on how to use FPGAs, including designing them into a circuit, board payout and soldering the little swine down.. BGAs.. urgh..

I'm also thinking it would be nifty to produce a board with FPGA and associated gubbins on it that has pinouts so it can be breadboarded or have headers attached. This would be great for future projects.

So far I think the pcb should contain:

FPGA(obviously..)

Power Supplies, it would be great to run it off a single 5v supply

a couple of ADC and DAC convertors

Program Flash

RAM

There is another project entered into the Hackaday Prize which is similar to DogEars, so to add a unique twist, I want to add a couple of ultrasonic transmitters, and investigate whether humans can be trained to use echolocation to navigate a dark environment.  This would be a fascinating experiment and would have positive benefits, for example for blind/partially sighted people.  

I want to investigate human ears, specifically the angle of hearing created by the shape of the ear, this could then be replicated with a 3d printed doodad to give the most accurate replication.  This would then allow the wearer to sense the direction of the sounds.