Digression warning-
gnu, if you have 'old' ears, an audiologist can give you new ones. Mine sold me on a pair- very good, except for the monstrous price she charged. I am deaf in one ear; the new aid has a transmitter one places on the deaf (or poor) ear that picks up and sends sound to the main hearing aid, thus keeping sound separated.

Which reminds me, a place in Toronto supplies hearing aids for those who are deaf (or partly so) in one ear but want to keep the defective ear free. Both channels are fed into the one good ear. Musicians are the main customers.