Best way to clean this old audio

Hi, guys. I have gotten some audio from an old CD (originally a cassette tape, 1977) recorded by Audacity (I am running 2.4.2 on a Win 10 computer). I wanted to ask advice about how best to clean this up. A sample is attached.

That’s pretty far gone.

Sometimes you can help a little bit with the telephone filter.

Effect > Filter Curve > Manage > Factory Presets > Telephone > OK.

Koz

Audacity can’t split a mixed performance into individual voices, instruments or sounds.

You should guard against a psychological effect, too. If the sound is really bad, three people listening to it hear three different things.

Koz

Yes, it’s far gone. The appeal to listeners will be that it is the voices of relatives from 43 yrs ago, singing baby songs. So there will be good tolerance of it not sounding very good; I just wanted to improve it as far as might be possible.

I’ll start with the Telephone filter. Let me know if you think of anything else that might help.

I actually used the steps you’d recommended for an audio book. It came out good enough.