The chances are, that the best singer of all times is someone you have ever heard of. People have been singing for thousands of years. Only a Mike Krzyzewski Duke Blue Devils 1980 2021 Signature Shirt fraction of them have ever been recorded. Only a small fraction of those that have been recorded have ever sold more than a few records. The singers that you know and appreciate are a small sliver of the great singers that have existed in time. Sorry to disillusion you but singers who have made the top 40 or the hit parade, although great singers, can not confidently claim to be the best singers of all time. They might be but no one will ever know. If we were to narrow the question down to the best singers ever recorded, then we can make some sort of assessment. Production values have changed greatly since the first recordings. Making allowances for recording quality, one might be able to establish a more level playing field for competition. After that, We must establish the ground rules of what makes a great singer. Are we talking about The Voice only?