Update, TLDR: given multiple semi-written lines of music, which line should be deemed the cantus firmus before working on the counterpoint of the other lines?

Given a "free" (?) soprano line (by this I mean not of any consistent rhythmic form, such as just half notes or just whole notes, etc) and a bass line in first species (whole notes only)--I believe, relative to one another, these linear structures would be called unaligned and not parallel--how should I go about filling in the alto and tenor voices using species counterpoint? I would like for the for the lines to be "two-against-one" with the bass line (second species)? I eventually want to include suspensions (fourth species), but i'll let that go for now.

Should my point of reference be the bass line or the soprano line? Do I need to simplify/reduce the soprano line so that it is easier to see/build intervals? Essentially, I would like to know the most logical way to develop my piece give a free-flowing melody and a bass line in first species.

For reference, here is the music as is:

enter image description here

  • 3
    As written, this question doesn't really make sense. Species counterpoint isn't defined by individual lines — an entire line in whole notes does not make it first species. It's defined by the relationships between the parts and the types of movements allowed. It also relies on a cantus firmus, by which the other voices are determined. But OP doesn't have a cantus firmus (or, not one that adheres to the rules of species counterpoint).
    – Aaron
    May 17, 2021 at 16:22
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    Short of making any changes yet, can you give me a sense of your overall goal and why you are looking to use species counterpoint?
    – Aaron
    May 17, 2021 at 16:31
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    Is this a particular exercise from the Westergaard book? May 17, 2021 at 17:47
  • 1
    @286642, have you already done all the exercises the book has for species counterpoint? May 18, 2021 at 15:14
  • 1
    @286642 Try working through Fux. He writes out the exercises, solutions, and corrections to the solutions.
    – Aaron
    May 19, 2021 at 5:33

1 Answer 1


Given that you want two-against-one with the bass, it would make the most sense to use the bass as the cantus firmus. While you develop those voices, treat the soprano as a descant voice,1 which will help you keep everything in sync.

I do think it would be helpful to simplify the soprano so that notes fall (primarily) on the beat, then returning them to anticipations/suspensions once the other parts are in place.

You can have it both ways by simplifying the soprano for the purpose of interval-checking as you develop the inner parts, but then play it as written for evaluating the actual composition.

1 "Descant: an independent treble melody usually sung or played above a basic melody." (From Google search)


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