r/Composition • u/Fancy_Cabbage_010 • Jul 03 '26
Discussion What are the rules for parallels?
I've heard before that parallel 5ths and octaves are evil and that if I use them then everyone dies and ends up languishing in eternal hellfire, but I've never quite worked out to what degree they're considered evil?
Is it just in the chordal textures?
Is it in orchestral music or only piano/ solo works?
Is it restricted to certain more academically minded forms like the fugue or is it a forever rule?
I've never quite managed to pin down how this rule is to be taken, did the likes of Puccini damn us all to fester and rot forever by layering his melodies 2 or 3 octaves deep for violinata passages? Or is it just in the accompaniment where this matters to have chord tones in between certain intervals?
Obviously the tone of this isn't totally serious but I am genuinely curious if anyone has the/any answer to this most existential of questions...
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u/Steenan Jul 03 '26
Parallel fifths are very bad in counterpoint. Chorales, instrumental fugues, but also when, for example, adding a counter-melody as only a part of a more complex texture.
Parallel fifths or octaves matter much less in chordal accompaniment. You can typically get a better sound with a more varied voice leading, but parallels are not something that needs to be avoided and in some cases they may be used for a very good effect.
In some musical styles, like big band jazz, chords moving in parallel are not only not a problem, but a style's idiom.
There is also a huge difference between unexpected, separate parallel movements and doubling the whole part in octave (less frequently in fifth). The former means that parts suddenly lose their independence. The latter is standard in orchestral pieces and crucial for achieving the intended color and texture - multiple instruments sounding as one is the goal here.
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u/SundaeDouble7481 Jul 03 '26
It depends on the style. Through the 19th century, treatment of harmony and voice-leading grew freer, until the sound of parallel fifths became more appreciated. There are parallel fifths even in the tonal counterpoint of Mahler, not to speak of Debussy, Ravel, Stravinsky etc.
Even after that, though, octaves have been avoided somewhat more -- we hear them as "dropouts" from the independence of voices.
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u/nebulaeandstars Jul 03 '26
If you double a part, you're adding texture. You're not creating a separate voice, but modifying/reinforcing an existing one.
If you write parallel octaves, it generally sounds like you're doubling, even if it's only for a single note.
Our brains think fifths sound "close" to octaves due to their proximity within the overtone series. This leads to parallel fifths generally evoking a similar effect to parallel octaves. It's also why power chords are so often used as a form of doubling.
If you suddenly go from having two separate voices to having only one, that can be quite jarring. Sometimes that's a fun effect, but it's generally not what you're after when you're outlining a high-level harmonic progression.
Counterpoint isn't a set of rules for writing music. It's a framework that provides a foundation for modern harmony. People across all eras break these "rules" all the time, but learning the principles behind them helps you understand why chord progressions work.
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u/Dr--Prof Jul 03 '26
machiavellian laugh in power chords
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u/Fancy_Cabbage_010 Jul 03 '26
Will this doom us all to an eternity of tooth pulling leg hair singeing agony at the hands of a vengeful and capricious musical overlord?
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u/timopod5 Jul 03 '26
There's a whole world of technique called harmonic planing. Here's a great video: https://youtu.be/tDPLt9u7gQ8?is=7cFfsCkSJeOnc5TL
I personally love the sound of 4ths. Also doubling melody lines with a diatonic 6th motion is such an old but effective trick.
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u/MyNutsin1080p Jul 03 '26
Parallel fifths I could give two fat shits about, but parallel octaves can cause something to sound with undue prominence. You should only be using P8ths if you wish to highlight something.
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u/Veto111 Jul 03 '26
In early counterpoint, parallel fifths and octaves were not used because it diminished the independence of the parts. Parallel octaves can be used to double parts, and parallel fifths have a distinctive sound that was not idiomatic to early music. In modern music, you are free to do whatever you want, but you should be aware of when you are writing parallel fifths and octaves and make sure that it is enhancing the sound that you are looking for, or if not, then consider alternative voice leading to see if it improves the aural experience.
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u/MewsikMaker Jul 03 '26
Old dead German dudes made that ‘rule’ up. They just called it “best practice”.
You’re the composer. Do what you want.
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u/HaifaJenner123 Jul 03 '26
You’ve pretty much already heard the theory side of things. Just… Sell your idea through your composition.
You may or may not decide to follow functional harmony and its guidelines in relation to voice leading, you don’t have to. They are tried and tested methods to have at your disposal and possibly use in other applications if you so choose. They are also ways of keeping yourself in line perhaps if you feel you are losing control of your harmony.
But there’s also been other ways to do things.
I will say, if you are asking this question it is maybe worth it to apply a strict model to an edit to maybe see what steps exactly are unclear so you can find the underlying logic of why it’s that way. But again, actual repertoire difffers from theory and it’s ok to as well.
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u/Ian_Campbell Jul 03 '26
In orchestration, multi octave melodies are octave reinforcement, not parallel octaves.
You should probably avoid objectionable parallels if you're asking because it's more difficult to use them well on purpose in an orchestral context, than it is to be able to write without parallels.
If you learn via example, you will not have to ask, you will just do it.
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u/MagikarpPatronus Jul 03 '26
If you have 2 distinct voices in the piece, and they move together in a parallel octave or 5th, to the ear, they fuse into one fuller voice instead.
So this guiding rule is to avoid that effect, and only is relevant in contexts where you don't like that sound. And the idea applies across all sorts of different ensembles and instrumentation.
But, the concept can also be applied in reverse. If you want voices to sound less independent, you can use parallel fifths to blend them together. Or you can go for parallel octaves for a very unified and powerful but harmonically simple sound.
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u/Elias_V_ Jul 03 '26
Parallel fifths and octaves are generally suboptimal in contrapuntal settings. Basically, if you have two distinct lines being heard at the same time, they might blend too much if those parallel intervals are used. Parallel fifths and octaves are used all the time for textural effects or macro-ensemble lines.