I was searching for a good alternative for a MIC and I came across this project. http://georgielabs.net/
Basically you have to install the Soundwire server on Rasbian and connect your cell to it (via app, auto connect is available) and then run your commands speaking to the smartphone, which is handy cause you mostly have on on you. MIC distance would therefore not be relevant. (can even configure it over WAN)
You could also have the default audio played over the smartphone.
I'm quite new to the project so I'll have to figure some stuff out before the testing starts. Would love some help!