There are many types of microphones, usually designed for a specific purpose. There are carbon, dynamic, pizeolectric, condenser and others. Some will sound 'metallic' (tinny), since they typically that don't have a full frequency range. Sort of like speakers. A 'woofer' doesn't respond to high notes and a 'tweeter' won't do the low bass notes.
Notice the difference in quality between two types of mics in the attached clip.