The Differences Between Vocal & Instrument Mics
Just like speakers, the enclosure that a microphone transducer is mounted in affects how it sounds and what it picks up. The same transducer can be built into a vocal and instrument version. So getting a microphone designed for a specific sound is easier and more effective than adjusting the input EQ.
The next two major categories of stage microphones are VOCAL and INSTRUMENT mics.
Vocal mics are designed for the application and include a presence boost and pop filters. Presence boost is the EQing of the frequencies between 800Hz and 3KHz to enhance your sibilance sounds (intelligibility, ask Sandy). You can sing into an instrument mic, but you have to use input EQ to add boost and cut where needed. Dynamic vocal mics also have a proximity bass boost many vocalists use as an effect. Getting close to the mic increases low end. Every mic sounds different. If you can demo different mics, you can find one that makes you sound best.
Instrument mics should have a fairly flat response curve. Condenser mics have better high end for cymbals and are usually small and light. Dynamic and especially large diaphragm dynamic mics have great low end and high SPL capabilities. What does the musician want to sound like? A flute can sound good through a vocal mic, less breathy sounds and presence boost. But a condenser instrument mic will pickup all the detail. I like clip on horn mics because players overdo dynamics sometimes and back too far away from the mic.
This isn’t the studio. When playing live, you should close mic everything for a clean sound.