Typically, the microphone that comes with your receiver has been VERY specifically selected to work with any in-built calibration and setup software. I don't think the microphone needs to be particularly good, it just needs to be consistent. So, they calibrate to something VERY high end, then use something really cheap, but repeatable, that then does a great job faking it. Using something not calibrated specifically to your Onkyo is more likely to cause negative side effects.