Good afternoon everyone!

Sometime 2 years ago I started practicing voice leading for 4 voices, but since I had to spend all my time on school I kind of stopped halfway. Since I graduated I've picked up practicing it again from the beginning (using a book) and I'm somewhat confused about the rule regarding hidden fifths/octaves.

I have to harmonize connections on I - IV - V in root position, but I feel like it's nearly impossible to avoid hidden fifths/octaves at all. The book stated that they are OK in the outside voices if the interval in the bass is bigger than the interval in the soprano, but if they appear between the other voices, "the ear has to decide" if it's acceptable or not. Now my musical ear is developed pretty well but I think this rule is a bit too vague since what one thinks is OK, the other may disagree.

So my question: What exactly are the rules stating whether hidden fifths/octaves are acceptable or not?

Voice-leading exercises I did last night.

This is a little exercise I did yesterday. You get a given bass in root position and you have to harmonize the chords. I haven't checked the exercise entirely yet, but as you can see, there's a hidden octave between bar 2 and 3 between the bass and alto going from A - C to D - D. I could make the alto go from C to A below instead to avoid that, but then there would appear a hidden fifth between the tenor and alto and I believe that's worse than the current situation I'm having now. As far as I can remember my music teacher once said that they are allowed, AS LONG as the lower voice has a bigger interval than the upper voice. Can somebody confirm this?

(PS. Don't mind the erase marks etc... It's difficult focussing at 1 AM... ^^)

  • If you want to keep the current soprano line, I would say that you're better off (by classical rules) in keeping the middle voices higher- then you don't run into these problems. By half notes, if the tenor and alto voices at the beginning are are e-a, d-f, b-e, c-e, then there's no problem. As a general rule, if you keep to contrary motion (as far as possible) between the outer voices, and keep the top three voices close, most such voice leading problems will take care of themselves. Commented Jun 22, 2017 at 14:18
  • Yeah I figured out that, since these are the first exercises, it's better to keep it simple and boring for the sake of really memorizing the rules and once I start working out inverted chords, I have more possibilities
    – koeno100
    Commented Jun 22, 2017 at 16:47
  • From a purely musical point of view, I would be more concerned that the bass and tenor are separated entirely by unisons and 5ths, except for one third. Remember the interval between bass and tenor can exceed an octave, and give yourself more space for the upper parts to move in.
    – user19146
    Commented Jun 22, 2017 at 19:36
  • You are right that IV-V in root position is always problematic, and even more so in the minor key because of avoiding augmented second interval, unless you are using the melodic minor scale where both chords can be major, or both minor. It's worth spending a bit of time systematically writing out every possible IV-V progression that follows all "the rules".
    – user19146
    Commented Jun 22, 2017 at 19:40

3 Answers 3


Wow, you are worrying too much XD

The canonical answer is:

A hidden octave or hidden fifth is forbidden only if the octave or (perfect) fifth is formed by the Soprano and another voice, and that the Soprano is jumping (i.e. adjacent notes do not form a second, but is a third or further away). This is because, in such cases, hidden octaves and fifths are too conspicuous. In your case, both voices are inner voices, the the octave is allowed, and in fact is completely normal.

If you are composing real music, the more important consideration would be the style of your music. If you are not composing common period music, the problem vanishes XD


A hidden fifth occurs when an implied consonant passing note would create a parallel fifth. A hidden octave occurs when an implied consonant passing note would create a parallel octave. So in your example, the motion from A to D implies a consonant passing tone A-C-D, and of course C-D and C-D creates a parallel octave.

Hidden fifths and octaves are admittedly a gray area, and depend on context. For example, if you are writing an eight-part piece for double choir, hidden octaves and fifths are perfectly acceptable, but if you are writing a three-part piece, they are completely unacceptable.

In four-part harmony, generally speaking, they are allowed between middle voices. Honestly they only become an issue when they occur between soprano and bass and the the soprano is the voice with the implied passing tone. Sticklers may point out your hidden fifth/octaves between the bass and soprano when the bass is making the leap, but you can see them all the time in masterworks.

You can avoid hidden fifths or octaves with

(a) Unusual doublings, e.g. omit the fifth in one of the chords and double the third, or

(b) Contrary motion. If the consonant passing tone results in an antiparallel octave or fifth, it is OK. When moving, for example, from IV to V, it is common for the bass to ascend and all other voices to descend.

You could also avoid them by using an anticipation or suspension. This is sort of cheating, but there are examples of Bach doing it so it must be OK, right?

  • By "consonant" you mean "diatonic", right? Commented Feb 17, 2023 at 17:40

It depends! Your fourth up in the bass and second up in the alto could be a permitted "horn fifth" or may be absolutely forbidden, depending on the style of counterpoint. Here's Schoenberg on the topic, from "Theory of Harmony" page 61 and following:

Not kennt kein Verbot! - Necessity knows no law!


Hence, exceptions were established, declaring: Hidden octaves and fifths are permissible provided they occur between two middle voices, or at most between a middle and an outer voice, so that they attract less attention. And: hidden octaves are better when one of the two voices moves by step and the other leaps a fifth or a fourth. Or: it is 'least objectionable' when the upper voice is the one that moves by step, say, from the seventh to the octave, or from the third to the fourth.

(There is also the "Mozart fifth" but Mozart apparently mostly used parallel fourths instead of parallel fifths for those...)

  • It should be treated as the same level of issue regardless of style as counter point is the study of Independence between voices. So hidden octaves and horn 5ths will weaken the independence of the lines which is sometimes desired, but specifically not in the study of counterpoint. While hidden octaves aren't necessarily a show stopper in every case, the do weaken the Independence noticeably.
    – Dom
    Commented Jun 22, 2017 at 15:41

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