Graeme explained on 18/11/2018 :
Earworm. An instrumental, as far as I remember, but with 'da da da' voices.
Possibly/probably 1960s.

Da da da da
(lower key) da da dum dum,
Da da da da
Dum dum dum dum

Or something like that ...

Possibly used as a DJ theme, or similar.

Now I have an earworm. I know the one you mean, later than that,
possibly 1980's/ 1990's.