Species Counterpoint, I am having trouble

I am trying to get to grips with this, so many rules and guidelines but I love it. Some general tips on how to go about it would be wonderful but I have two specific questions.

With 1st and second species, the tutorials tell me to pick intervals with either consonance or dissonance in accordance with the rules but I have seen no rule or mention (yet) of checking to see that the intervals keep consistent with the chord progressions.

If writing for a few instruments (I am nowhere near this stage) does one use counterpoint with the lower notes and the highest (the melody line)
of the piece in each case? In other words do CP rules apply for all classical music?

I do hope I am making sense.

Regards to all of you

Not exactly. However, if you analyze lots of classical music, you will notice that the melody (or upper parts) and bass tend to obey 2-part counterpart. The "rules" (for rule, read "widely used procedure") are a bit relaxed from Fux and other pedagogues. The idea is that if the melody and bass make reasonable two part harmony, the rest of the piece will sound pretty good. Both the melody and bass are "exposed" (easy to hear even for the non-musician) so these need some care. In one sense, harmonic progressions arise from the confluence of melodic lines; the extreme example would be Byrd's masses or Palestrina's work. In the baroque, a single (maybe ornamented) melody becomes the usual rule (except for fugues and canons) with a basso continuo and some harmonic support. The "classical" and later periods simply introduce strongly a sectional feeling by having lots of cadences to articulate the structure. Still, the bass and melody make pretty good counterpoint. Note that lots of phrase structures have harmonic progressions like I-X-X-X-X-X-ii-V-I or similar where X is anything that fits.

I've read somewhere (and it's easy to.see) that Bach's counterpoint often matches to fairly simple chord (degree) progressions.

Beside.that, it is useful to learn about the difference between structural vs linear degrees (chords); that is, the core of Schenker-Salzer analysis.

Also, a useful feature within cp inversion: as you invert a given CF-CP, you will.eventually get a change.of key (namely, a new.key a.5th or a.4th apart.from the former one).

Greetings

Thanks both of you,food for thought. My main difficulty is keeping to the "rules" as you put it ttw. Athair, you have got me reading Schenker stuff.

I am pleased I am interested in this, it seems that things get more complex when there is more than one answer.

Many thanks.