There are lots of perfomers with a small range but are great singers. Bing Crosby had not a lot of range but amazing control and great power. Johnny Rivers was is the same way. No great range but good style. Kenny Rogers has a week voice but is a unique stylist which makes hom bankable, And anyone who remembers Malvina Reynolds remembers a great writer and a no generous voice. But she had a way with it. Jim Post has amazing Range power and control over a voice I can take or leave.

Joni Mitchell has a very good voce which I can't stand. I know its a good voice because my sister says so and Martha wouldn't lie.

I know a woman who can sing in three keys at once, none of which is anyone playing in. She is totally tone deaf but she is enthusiastic.

I think you may have aske d the wrong question, What makes a good singer may be better than what is a good voice,

Don