Old Analog Recording

I have an aiff of a bad analog recording of my high school choir from 1976. What are the best strategies for getting it to a place where it can at least be understood?

Audacity 2.0.2/DMG
OSX 10.11.4 (El Capitan)

There’s a fuzzy rule that if you can’t understand words now, there isn’t much we can do.

The only tool likely to help at all is the “telephone filter” in Effect > Equalization. It makes your voice sound like a telephone for the same reasons your telephone sounds like a telephone. It’s a little easier to understand.

This isn’t likely to help at all if the show is music.