Bach Sinfonia #12 in A Major - confusion

[shaunarundell]

All,


I know there have been quite a few posts and discussion here around the Bach inventions and WTC. I think I have read them all, but I am still a little confused and could do with some help with Sinfonia 12.

My  problem identifying the themes or motifs, splitting out the 3 voices and determining their entry and exits and in deciphering what parts are  thematic and what is extra or decorative.  I would like to identify the voices so that I can practice them independently before putting them together

A few questions

1.  I understand this piece is a Fugue - is this correct ? I guess my questions below would then be general questions around fugal structure.
2. The motif starts at bar 1 and continues for how many measures ? I can see 2, 4 or more being possible
3. It starts in bar 1 with both  a treble and a bass part. Are the bass and the treble both considered part of voice 1 (and carried through into the other voices) or are they 2 voices or is the bass just a harmonic decoration.
4. I notice that there are minor modifications to the theme as they each enter ?
5. Once each of the 3 voices have entered - bar 1, bar 3 and bar 5,  I am not sure how to proceed with the Analysis and how to move forward with the analysis with rest of the piece

thanks for your thoughts
shaun