Hello all. I'm trying to record some songs for a choir group that I'm in. We're actually using a keyboard connected to my iMac via MIDI to USB. But the mic that we're using is the internal mic on the iMac. After playing the track, there's too much background noise being picked up and you could hardly hear the vocals even though we're right in front of the iMac. Without spending too much money, is there a USB mic out there that can eliminate background nosies decently and get good quality on playback? I'm in need of the mic ASAP so I would really appreciate any advice. Thanks!