I want to build some kind of audio processing unit. I would connect some microphones to it (like those in phones, not the big ones for singers). I have some experience with reading the raw audio data in Android, that’s an abstraction level I can handle. Everything that gets more low level is a bit hairy for me. (Raw means here that I read integers from a buffer.)
Is there a hardware platform that allows me to easily connect microphones and read the raw audio data? And I want to connect it to a computer over USB to transfer the raw audio data. I think the further processing would happen on the computer, like Fourier transformations, etc.
I have heard about Arduino, does it provide a good abstaction level for that? What platforms could I use instead?
No reason to use an Arduino for this, a standard PC sound card works just fine! What you are asking for is exactly how it works. You can capture audio, and read sampled values from the buffer.