How do you approach consonance/dissonance when making music?

Question

I used to think it was absurd to think of consonance/dissonance as anything but an objective measurement, but after doing more research and reading posts like this How does the harmonic series affect consonance? it seems to be more complicated and not so straightforward.

It’s satisfying to think that consonance can simply be described as how many harmonics two intervals share, and this works for unisons, octaves and perfect 5ths, but when it comes to other intervals like the perfect 4th, this simplistic definition doesn’t really hold up.

Although understanding the science of sound will allow me to better approach making music, my priority is still making music. So, instead of trying to make a groundbreaking discovery in science, I would rather focus on other ways to approach consonance and dissonance.

I was wondering how others approach/think about consonance and dissonance when making music. I still want to consider the things we do know/understand about the harmonic series, but I also realize that there is no ‘end all’ theory that can be directly applied to making music.

What are some ways you approach consonance and dissonance? How do you think about it when making music?

Answer 1

I always think of consonance and dissonance as representing "rest" and "motion" respectively (in the style being used.) Mostly I write short dance pieces (ballroom mostly). I tend to put dissonances in to break up longer mostly consonant phrases. Often with lyrics, one uses a slight (or big in some cases) to mark an ensuing phrase end.

Ludmilla Uhleha has a good discussion of consonance vs dissonance in various styles.

While I do know the various interval ratios, I don't think this gives a good enough explanation of consonance vs dissonance (the fourth as mentioned in the OP); composers over the years have treated dissonance variously. In Renaissance music, (Palestrina is the usual example), there are few dissonances and all have standard resolutions, however, because of the consonant texture of much of the music, what would now be considered a mild dissonance really stands out. In blues, the I7,IV7, do not act as dissonances; the V7 may act as a dissonance when used in a V7-I7 context but in others, it's just a V chord with a thick texture.

Actually, the real advice is to be cognizant of the amount of dissonance being used and decide by ear what sounds best. (Easy to say, not so easy to do.)

Answer 2

My thoughts on consonance and dissonance have kind of come full circle for me. When I first came across the terms early on in my studies, I was focused on understanding how they figured in the mix and what I needed to be aware of when I was figuring out harmonies. Eventually I came to view these characteristics of harmony in much the same manner as I view verbal expression when I speak. When I ask a question my expression is different from when I make a declaration, there is a different attitude expressed. The tools that I use to determine whether or not my statement is a question or a declaration are automatic for me. I don't stop and think about them when I'm using them. In much the same fashion, consonance and dissonance in all their varying degrees are like those tools of expression. I know the sound of each one and I can use the way they sound to duplicate the sound I hear in my head when I'm playing. At this point it is pretty much an automatic process for me.

Answer 3

The harmonic series that you describe was discovered to be related to our perception of consonance and dissonance by the German Physicist Herman Helmholtz in the late 1800s. The concept was known to us (the human race) for a lot longer than that. Helmholtz was out to provide an objective description of why some intervals are considered "unpleasant" and other harmonious. The human factor may still be subjective. You cannot force me to say I like the perfect 5th and cringe at the minor 2nd, but the opinion of the masses is at play here. My point is that the objective measure you have read about may not be the last word on the subject and just one of many ideas. It is also describing qualities of WESTERN CLASSICAL music and as such is biased by race and ethnicity. In other cultures sounds that a Westerner might consider "dissonant" are judged as beautiful and harmonious. Also, the actual frequencies of notes have changed over the centuries and the harmonic sequence may not have always been present in the intervals, and some that were present may be lost! So, in reality you can use tones any way you want to create the effect you want with your music.

You mention the 4th as an example that doesn't quite fit the paradigm. In fact many people judge the 4th to be very dissonant. The 4th is an inverted 5th and under the correct circumstances can sound consonant, and in others dissonant. I think that how we perceive things is relative to the tonal landscape.

That being said there are some "classic" uses of these ideas in western classical music that are part of the modern tradition.

Consonance: This is usually harmonious and intervals are not EITHER consonant or dissonant but have a degree of each quality. Generally 3rds and 6ths are judged to be consonant.

Dissonant: This is usually thought of as "clashing" or "tense". Seconds, sevenths and the diminished 5th are judged as dissonant.

The 5th is really quite obnoxious! We generally do NOT want 5th harmony and frequently voice chords so that it is absent or on combination with other intervals to "soften" it. The reason is that there are TOO many matching harmonics and this creates an opportunity for the interval to seem louder than one would predict by adding two incoherent sources. Some texts refer to it as a "resonant" interval.

In any case one classic use of dissonance and consonance in classical and modern western music is the authentic cadence or resolution. We commonly use the chord change V7 --> I at the end of musical phrases. The V7 chord has a diminished 5th from the two notes (Ti, Fa), or (7, 4), of the key and the I has the interval M3 from (1, 3). There is a natural movement (7, 4) --> (1, 3), 7-->8(1) and 4-->3 or dim5 --> M3. The dim5 is sometimes referred to as the most tense interval and M3 the most harmonious. The idea is to create harmonic tension and release it. This "feels good" or is an aural representation of other types of tension --> release. It could represent a fight that resolves, a sickness that is cured, being lost then found (reference to Amazing Grace, and Mahler's 4th symphony) or whatever you think of.

In terms of "approaching" consonance and/or dissonance this is it's classic use. In Jazz we see this idea hyper extended. A lot of classical music just moves diatonically from I-->V and back, or I-->IV and I-->V but ends on V7-->I. Jazz player will often treat each chord as a temporary I and insert its V7 thus create the sound and feel of resolution more often (I'm glossing over this quite a bit). For example the simple set of changes I-->IV-->V for any rock tune (or country, or classical, ...) might by augmented to read, I-->I7-->IV-->#IV-dim-->V9-->V7-->I or some other variant. Each place is "walked into" from an appropriate chord that emphasizes the cadence, or the tension release feel produced by moving dissonant intervals into consonant intervals.

Once you realize this you can really go hog wild with deepening the dissonance in the chord stream and some players (myself included) become fascinated with the tension to the point where you don't want to release it. In Jazz this could be what is described as being "Out" harmonically. One can create this tension to a lesser degree by simply using modified chords that have embellishments. The two features of the V7-->I movement are the D5-->M3 and the chromatic movement of 7->8 and 4->3. So introducing any new chromaticism will generate this tension -> release feel to a lesser degree. Again you hear this played with a lot in Jazz.

Going even deeper it stands to reason that if you used an interval smaller than a half step you could create even MORE dissonance. On instruments like the guitar where we can bend strings it is very common to bend slightly out of tune (1/4 tone or 1/2 of a 1/2 step) and bring the note back in tune. This can sound very haunting and when done right really lave a mark on the listener. One player who comes to mind as a master of this is Jeff Beck. But all blues players make use of this to some degree.

Last point I'd make is that "dissonance" and "consonance" of intervals are somewhat frequency dependent. So a M2 played by a Bass will sound muddy and you may even hear rapid beating of the fundamentals which is a physic based cause of "dissonance" according to Helmholtz. However the same interval played by a violin in the higher register will not be that dissonant.

People love playing with this phenomenon and I'll leave you with an example I use when playing the classical guitar. When I play the A on the second fret of the G string it will excite the n = 2 harmonic of the open A string (this is the same note). The excitation can be so great as to make the harmonic as loud as the plucked note after a short time. I then bend the plucked note slightly until I hear the beat frequency and try to match an 8th note or 16th note tremolo in the tempo of the tune I'm playing. This is not an attempt to replace the tremolo technique but it sound really cool, almost etheric. And even though it's horribly out of tune by matching tempo it sound "correct". This is a way of manipulating what the audience hears and feels by manipulating the physics of the instrument. I will eventually drop the bent note down which creates the classic feel of tension release.

Answer 4

I usually think in Consonances/Dissonances as Hindemith (et al.) approached this matter. He ranked intervals from most consonant to most dissonant, and in every melody, chord or sound mass I write I'm always thinking of these intervals and how every pitch is relating to others (as one normally would do in counterpoint thinking).

In his system (somewhat explained in his The Craft of Musical Composition [spoiler alert: dense and in many ways nonsense book, but it stills a cool reading]), he related every chromatic pitch class to the first one (0 or C, for example) without harmonic series considerations - his system is tonal but not diatonic. He also classifies chords, but I don't use this very often. Guerra-Peixe called this as "Acoustic Harmony" and, along with neo-Rieammanian theory, is useful to create and conduct voices in non-diatonic contexts.

One may think as consonance-dissonance spectrum as a sound analogy to light-dark dichotomy from visual arts. This helped me when creating centerless music - I'd construct music on free pitch movement, but the density of each chord is based on how light or dark it was and what I'd like in a given moment.

This is a rather important discussion, not only at composition topics, but also in performance studies. As an example: we can sense chords more or less tense based on how the conductor communicate tension to his group.