I have a 2010 cMP and I just installed sierra. I'd like to try Siri out, but I need a microphone to do it. I am not sure how good of a mic I need. Part of me would like to use the old PlainTalk mic that apple used to ship with their computers decades ago, but that would take some reengineering to get it to plug into either the line in port or a usb port (it used a proprietary plug that helped power the mic). So anyway, what usb or line in mic works well with siri without breaking the bank on a pro audio level device like a blue snowball, blue bottle, sennheiser etc? Alternately, if anyone has ideas on adapting a plaintalk mic to usb, let me know. So far I know that the plaintalk uses between 5v and 9v and that the Tip (White) is the power supply for the enclosed preamp, Ring (Black) is the line-level output from the preamp, and the Sleeve (Shield) is Ground. On ebay there are lots of USB audio adapters with built in mic jacks, that look like they could possibly be modified. I wouldn't mind cutting off the wires on the PlainTalk, and soldering them directly to the usb board. Since USB is supposed to supply 5V and 500mA, this might be perfect to run the PlainTalk mic. I am not sure what amp draw the PlainTalk mic might have however.