Recently I have been performing a series of Cabaret performances with my long-time friend and student Peggy. She is a classical singer who has flown the heights of The Queen of the Night, but who can also sing show tunes convincingly. I, at 80 and a half, am amazed that I have any voice at all, but if Elaine Stritch and Barbara Cook can still do it, so can I.
A number of my students have sung both classical and show songs but that doesn't work for all voices. Men have an easier time going from opera to pop than women, especially women opera singers. There are several disastrous examples of Divas trying to let their hair down and 'get with it'. Renée Fleming's cross-over albums attest to this fact. Eileen Farrell, who had a much bigger voice than Renée, made the switch brilliantly.
I tell my students who sing show, pop, and even rock, that your technique must not change when singing a different type of song. It is really a matter of style.
One of my students has his own band, for instance. He also is a soloist in church and has done regional theatre successfully. He told me only yesterday that in the past his voice would tire when singing with his band. It no longer does that. He has learned a good, free technique which he can adapt to what ever kind of music he is singing.
Years ago a young woman came to me with serious vocal problems. She had been singing rock for a number of years and her vocal cords were threadbare. It took a long time and a lot of convincing, but I finally got her to sing on a lower breath and a much better technique and she was vocally happy for the first time in a long while.
Early music singers for a long time, especially the sopranos, sang with what Anna Russell called the 'British Pure White Tone'. This is popular to this day, unfortunately, with some choral conductors who expect forty year old women to sing like six year old boys. Here it's all a matter of vibrato. Any voice with absolutely no vibrato is a voice that is being held. Vibrato is a natural result of the muscles of the larynx working (involuntarily, by the way) and the air passing between the vocal cords. Thank Heaven, along came Lorraine Hunt Lieberson who proved that one can sing early music with a full rich tone and be perfectly in the correct musical style for the period.
We only have one set of vocal cords. They are endlessly adaptive if one uses them properly with a low breath and a free technique. So- Cabaret-Smabaret.
Just sing the damned song!