I want to create a microphone array that can be connected to my laptop. Previous discussions in stack exchange and other forums suggested me to get a USB audio interface. I would want to do a lot of real time signal processing on the sound arriving at the microphones (To be precise, I want to calculate the time delay of arrival of sound at the different microphones). But from what I saw, the audio interfaces are a bit expensive. But external sound cards are not! Here:
Can I use an external sound card to receive input from multiple microphone (create an array, that is).
I will require 4 mics, but right now I need to do it with only 2 mics to test the algorithms. Sampling rate would be around 40Khz.