Les Cargill wrote in news:Srdve.186089$w15.48496
@tornado.tampabay.rr.com:

Let's stamp on this one. Raising the chin makes anybody sing worse. It
stresses the vocal cords and limits the intensity of sound badly. Go
to any reputable singing teacher or voice coach, and "keep the chin
down" is one of the first lessons you will get.

Thanks for the correction. I'd actually learned this from a
school choir director.

If keeping your chin up also keeps you from slumping, it's OK. Good
posture means better back support (the power singing muscles are in your
lower back) and more room to expand your lungs (shoulders back). Then put
your chin down and relax your jaw.