A student sent me a screenshot after lecture four, circling four bars of tied notes and asking a fair question: do you keep this pattern going for the whole exercise, or is there a point where it's supposed to stop? The pattern he meant is the suspension chain, prepare, suspend, resolve, over and over, one tie per measure. He assumed he'd missed a rule that told him when to break it. There isn't a rule. There's a judgment call, and it's worth learning to make on purpose instead of by accident.
A suspension is three events tied to one tone
Fourth species counterpoint sets a moving voice in half notes against the cantus firmus, the fixed whole-note melody every species is written against, and its signature move is the suspension: a note held over the bar line so it turns dissonant against the note underneath, then steps down to resolve. Three things have to happen in order for that to count as a suspension rather than just a wrong note.
The preparation sets the note down as a consonance. Before the tie, the note you're about to hold over has to agree with the voice below it: a third, a sixth, an octave, something stable. If it starts dissonant, there's nothing to suspend.
The suspension holds that same pitch while the bass moves under it. The bass changes on the strong beat, the upper voice doesn't, and now the two disagree: a second, a seventh, a fourth against the bass. That disagreement is the whole point. It's where the tension in the phrase actually lives.
The resolution steps down by a second to a new consonance. Not a leap, not sideways, down by step. That downward step is what tells the ear the dissonance was intentional and has now been spent.
Do that four times in a row and you get exactly the pattern my student circled: tie, dissonance, step down, tie, dissonance, step down. It sounds orderly because it is. It also starts to sound like a machine if you never do anything else.
The chain breaks when the line needs air, not because the rule expired
Strict fourth species allows you to drop the tie occasionally and let the two voices move together for a measure, what's usually called breaking the syncopation. Students read that permission and ask the same question in reverse: if breaking is allowed, why not do it more, why not skip half the ties and keep things interesting?
Here's the practical limit. Every suspension you skip is a bar where the line stops pulling toward a resolution and just sits in consonance. One or two of those across an eight or ten bar exercise reads as phrasing, a breath between gestures. Four or five and the exercise stops being fourth species at all. You've written note-against-note counterpoint with a couple of ties left in for decoration. The tension-and-release architecture that makes the species worth practicing is gone, and so is the reason a listener's ear tracks the line at all.
So the chain breaks for a reason you can name: the melody wants to leap somewhere the suspension pattern can't reach, or four straight measures of the same shape have started to sound predictable before the phrase is actually finished. It doesn't break because you got bored writing ties, and it doesn't break on a schedule. You're not following a rule about when suspensions are allowed to stop. You're listening for the moment the line asks for something else, and trusting that you'll hear it if you've spent enough time inside the pattern to know what it sounds like when it's still working.
Train the ear to notice the difference before you write it down
The fastest way to learn this isn't reading about it, it's writing short exercises and testing your own ear against them.
Two voices. Eight bars. Tie every measure for the first four bars, prepare, suspend, resolve, exactly as drilled. Then, starting in bar five, break the chain exactly once, wherever the line tells you to, and finish the last three bars back inside the pattern. Play it. Sing the top voice against the bass. Ask yourself honestly whether the broken measure sounds like relief or like a mistake you didn't catch.
If it sounds like relief, you heard it correctly before you wrote it down, audiate the phrase first and the notation just confirms what you already know is there. If it sounds like a mistake, that's useful information too: it means the break happened because you ran out of ideas for the tie, not because the phrase asked for it. Do it again. The goal isn't to get the rule right. It's to get to where you can hear a suspension chain and know, the way you know a sentence needs a period, exactly where it wants to stop.
The lecture that prompted the original question covers the full fourth species pattern on screen, with examples you can hear:
If fourth species keeps raising more questions like this one, I built a full course around exactly this kind of voice-leading work. It walks through all five species with the same emphasis on hearing the pattern before you notate it. It is over at uremusic.com/counterpoint-for-composers whenever you are ready.
New here? Start with my free course, Audiation: Inner Ear Training for Musicians, sixteen short lessons on hearing music in your mind. No card, no catch.
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Counterpoint Is How Independent Melodies Learn to Agree
Theory Is the Composer's Map: Why the Rules Are Worth Knowing
