Cardiod?Fig8?Omni? I need to purchase a usb mic for work to record eLearning audio. One mic has just cardiod, the other model of the same mic has switchable from cardiod to Figure 8 pattern recording to omni-directional. I think I only want to record a single narrator at a time, so I don't think I want the omni. I think Cardiod (heart pattern) is good because it picks up the diaphram sound but not sure what the Figure 8 is and I don't want to pass up the options; but i don't want to pay more for buttons that may just cause accidental mis-settings and bad results.