I am currently working on a piano piece and am at the same time trying to analyze its harmony.
I am puzzled by a small section where it seems to modulate from C major to C minor, but everything doesn't seem to work from a theoretical point of view (to be more precise, it doesn't seem to fit from my perspective, which is not professional at all).
On measures 13 and 14, the melody played on measure 11 and 12 is repeated, with an Eb instead of an E to suggest the tonality of c minor.
However the bass part, from my point of view, seems to be a deceptive cadence in Eb major, which lands on C minor. I assume it is a way of modulating whithout using a dominant seventh chord.
What bugs me is that, if we add up the bass part and the melody at measure 13, it makes an Fm7 chord with an Eb at the bass. This chord would make sense in C minor, but not in Eb major (the key of the deceptive cadence).
On top of that, if we in fact assume we are already in C minor at this point, the next chord (measure 14, Bb major) doesn't make sense because in C minor, there should be a B natural. Right ?
Sorry for the sloppy explanations and conjectures, but I could really use some help with that one. Thank you in advance for your answers.