In my punk band, our singer sometimes plays the melodica (basically a flute w/piano keys!). We have had a hard time micing it live, and although this isn't a recording question we'll be recording it soon. As far as live goes, what would be the best way to mic it without feedback? We have used a 57 and a 421, both with minimal success. To get the instrument loud enough in the mix (think marshall halfstack) I have to crank the gain, which leads to feedback. The 421 works a bit better with the bass roll off but I am hesitant to carry that thing around at shows with how easliy mics can "walk." I have been thinking about one of those "horn" mics with the clip and small diaphragm but I'm not so sure that would be any better. Any suggestions?