I have no education in music theory so I don't understand most of this... harmonic progression?Underlying
sequence of chords.
What harmonic progression? There are no chords in Machinary.
There are some synch chords, though you might have them sampled as single 'notes'. The bassline also implies a harmonic structure. I can do a chord breakdown of machinery (though it's pretty simple), if you think it would help?
Or do different instruments playing different notes count together as a chord?
In terms of harmony, yes. Even if they're not playing at the same time
And what's chord inversion? If I understood Wikipedia correctly, it's when you have say a chord of C5, E5 and G5; and an inversion would be G4, C5 and E5? (like the top/bottom note flips to the other end?)
That is it. Inversions have a similar effect to the original chord, but are usually 'weaker'-sounding in some sense.
If you think it'll be a good learning experience for you to do the brief as given, I can happily keep on this chit-chat if you feel it beneficial. If you would like me to give you a new (but similar) brief in a less-theoretical register, I can do that also.
can we please ditch the sadistic lyrics?
If you mean to imply that your mistress is a sadist, well, that would be correct