These unusual versions highlight many vocal and musical passages that were buried or mixed out of the final released mixes, or were edited out completely. In a couple of cases there are entire verses that were cut out of the versions released by ABBA back in the 70s and early 80s.
These mixes have variously been referred to as alternate mixes, early versions, demos or even different recordings. But in fact they are simply copied from the multi-track master tapes, with the volume of all of the vocal tracks turned right up, and the volume of the instrumental tracks turned down or right off. Several of these recordings include faults and drop-outs which indicate they weren’t properly mixed.
Once all the instruments and vocals were recorded the tape would then be mixed, treated with effects such as echo and compression, copied, edited and mastered for release. It’s very interesting to hear what Björn, Benny and Michael B. Tretow chose to mix and edit out of the final versions, to make the perfect pop records.
These recordings demonstrate the great effort that went into the many layers of vocal overdubs, most of which are barely heard in the backing “choir” on record.
The common theory is that these mixes were made by an anonymous studio engineer, roughly mixing the tracks to highlight the backing vocals for the arrangers and/or singers for Mamma Mia!, to hear the sounds of the vocals (rather than the words, as a few of the songs are in languages other than English). All the songs that have surfaced feature in the stage musical.