I provided a link to a website on the history of singing at the previous list of links I referred to in this thread. Here is a quote from that history regarding the advent of popular recorded and amplified singing. I've mentioned this in other threads, but it is worth quoting here.
click here

"Until about the 1920s there was no essential difference between 'classical' and 'popular' singing, though a fuller voice and greater technical accomplishment were demanded of opera singers than of those who sang operetta and popular songs.  During and after the 1920s the two styles became separate as popular singers began to use the microphone, for which a technique aimed at projecting the voice was no longer called for.  At the same time, Afro-American blues and vaudeville singers such as Bessie Smith and Ethel Waters were making their earliest recordings, which taught white singers to shift pitch and metre over a steady beat.  This oratorical or conversational style of singing, exploiting the contours and cadences of speech, was less concerned than 'classical' singing with vocal display or a sustained melodic line and was particularly suited to the radio and later to public-address systems in ballrooms and auditoriums which emphasized the projection of text rather than tone.  Because it was harder for sound engineers to accommodate a loud, resonant voice than to amplify a soft one, early radio performers had light, mellow, intimate voices (see CROONING).  Later singers like Bing Crosby, Perry Como and Mildred Bailey adapted their bigger voices to Afro-American phrasing and to the microphone by using half voice or head voice in the middle range and by singing, throughout their range, with less intensity of pressure on the vocal cords. " go to the website on the history of singing for the full article.

Although the article mentions that many popular singers do not depend on having vocal training but rather "on style, promotion and association with a popular repertory than on any refinement of the voice", many popular singers (and we are talking about the genre called American Popular music) DO use vocal training to protect their voice in long, successful careers, such as Tony Bennett.

Again, I come back to my statement that the good voice is the one that fits the song being sung. There are alot of singers who will eventually lose their voice by the style they are singing. There are some people who are born with pleasant sounding voices and natural talent that do not require as much guidance as others to stay on pitch or make a good sounding tone. There are some types of music that do have a nasal sound to them, that do have shouting, groaning, sounds that are a part of that particular type of tradition. This should not be in conflict with a person learning to use their voice the best way they can, no matter what type of music they want to sing.

THANK YOU Judy for providing your story on the development of your voice. Judy's testimony should give insight into the value of those who want to sing ANY type of music, including folk music, jazz, blues, and to have the PHYSICAL ability to sing the notes you need, the confidence to stand up in a crowd and sing, and the knowledge to protect your vocal cords from damage so that your voice gets better and better, singing all your life long.

Here is a link to "Singing" and related articles (the one I quoted) by Owen Jander and Henry Pleasants in The New Grove Dictionary of Music and Musicians.click here

-Alice