Hello
have you seen the new ANDROID QUAD CORE credit card sized computers.
They are just 69 dollars new.
An Android 4.1 "quad core" arm 1.8 ghz with 1 gig of RAM. (i think it's about 40 times more powerful than the rasberry Pi....but similar price. They also come with a CASE and free ship.
Model = ODROID-U
http://www.hardkernel.com/i think they have "digital micrphone over HDMI" meaning that many large screens that contain built in MICS will send that sound into the ODROID over HDMI.
otherwise the ODROID-U2 at 89 dollars has an analogue microphone socket on it
Vince.