This isn't set in stone or tried and tested under strictly controlled conditions, it's just a rough rule of thumb, and as these fab four flavours of 'Get Back' show Beatles tunes can just as easily be refried funky side up...
Get Back - Chris Clark
The Merseybeaters get given a Motown makeover
Get Back - Deidre Wilson Tabac
A bubbly,shuffely, loose limbed lollop-a-long re-work.
Get Back - Sarah Vaughan
A brain-frying team up between those beardy
Get Back - Shirley Scott & The Soul Saxes
A hat-popping, horn-stomping spectacular so fast and furious it rollocks along like a runaway train.
There's a couple of other tasty Beatles treats well worth grabbing...
BLTP's unearthing of a gorgeous rework of 'Rain' - nothing like the original and none the worse for it - here
And Larry F16's Beatles based million-hit-mix here