Crooners need a mike to make a sound - cannot be heard unaided - may have pleasant voice but no volume and not much carrying power - the ping or resonance you hear in a big or trained voice is not there

Singers can make themselves heard in medium sized rooms and project their voices whether trained or not without a mike - stand further back from mike as it only assists

How do I know 47 years of singing plus working as a teacher and singing everything from country music to jazz - cabaret - musical theatre and classical stuff