I recovered from the flu a few weeks ago, but my voice hasn't returned to its normal range. I'm a fairly high soprano usually, and have a comfortable range from about a Middle C to a high Eb.
For the past few weeks my top range has remained much the same, but I have a low B and A (and occasionally a G!) that certainly weren't there before. I also appear to have a lot more body in my lower range than I did before being sick - more of a "belt" - which I've never had before.
I've never heard of changes sticking around after an illness like this. Has anyone else had experience with this? Do you know how long it will last? (Can I keep it?)