Tuesday, March 3, 2020

Tonality and Dissonance

These two concepts are often confused, I suspect. We learn about tonality and dissonance in theory class, but we don't think much about how they are related or if they are related. Dissonance is a fairly easy concept, but one that is historically inflected. What is considered to be dissonant varies over time. A long time ago, thirds were considered too dissonant to use in a final cadence. In common practice harmony, almost any interval can be used, as long as it is resolved correctly. In a V7 - I cadence, the dominant chord contains the very dissonant tritone, but with the leading tone resolving up and the seventh resolving down, all is well.

In 20th century music a lot of dissonances were explored including clusters of semitones and even microtones.

Tonality is harder to define, but it usually involves the concept of "functionality." I gave the example of a V7 - I cadence. This is an example of functionality. A cadence really defines tonality. The function of a cadence is to define the key, the tonal center. The function of a leading tone is to lead to the tonic. The function of a seventh is to create a dissonance that is resolved into the tonic chord. Every note and every harmony has a role and function in common practice harmony. Schoenberg even thought about his twelve-tone system as being a huge extension of tonality.

Dissonance has a function within tonality, in fact, tonality depends on the use of dissonance.

But here is the thing, we sometimes think that what led to the obsolescence of tonal music was the over-use of dissonance, but you can have music that is not functionally tonal that also does not use a lot of dissonance. So-called "modal" music is an example. Modes, typically lacking leading tones, have a lower level of dissonance than tonal music. You could have musical structures that simply avoid both tonality and dissonance. For example:

Click to enlarge
That is the opening of Petroushka by Stravinsky and while what is going on there is not nearly as simple as it looks, one thing for sure, it is neither dissonant nor tonal. What we have is an oscillation between two harmonies with a melody above that that suggests a different harmony. One of the things that weakens the notion of a tonal center is the rhythmic structure. Fundamentally, in order to define a key in common practice tonality, you have to have some kind of dominant resolving to some kind of tonic and it needs to go from an upbeat to a downbeat. Pieter van den Toorn describes what is going on here as "oscillating simultaneities." The fact that they are a whole-tone apart means we don't really hear either as a "tonic" and that is despite the leap of a fourth from A to D that would often signal a dominant-tonic relationship. Look at that cello melody: we do get a C# but it is not heard as a leading tone because it is in a metrically weak position and because it leads away, not towards the D. Everything is "up in the air" which what makes this opening so exciting.

Let's have a listen:


5 comments:

  1. Tonality and dissonance, Bach, Stravinsky, ancient literature ... I can't keep up! Especially since these are all subjects I like ...

    Well, let's start with contemporary guitar ... I've tried to follow your composer, Bryce Dessner, to his lair ... I have to say, "Sorry. I just don't see any hospitable space for the electric guitar as guest member of or innovative accompanist for orchestra." One of the hallmarks of classical composition is the maxing out of a given instrument's potentialities. Only rock n roll has been able to accommodate the electric guitar to the max, that is, humbucker pickup, with a Marshall stack turned up to 10. It may be that the major and minor pentatonic scale is the only scale that works for the electric guitar at high volume. Jazz passing tones or chords are mostly indiscernible at high volume on the electric guitar. The guitar is a troublesome instrument no matter what context it shows up in. The classical guitar is too quiet for the orchestra pit; the electric guitar, too loud. In jazz, every instrument gets to blow its back off, but there's the guitar swishing along harmless as a snare drum, not too loud, not too obtrusive, just enough to barely know it's there. Then there's the jazz guitar solo, fine as far as it goes, but the sax really steals the spotlight for jazz solos ... the guitar can't really touch it in jazz. I suppose jazz fusion incorporated loud electric guitar with John McLaughlin and friends but even there you see that subtlety must decrease as volume increases. I've often thought jazz guitar players are essentially classical guitarists with contemporary melodies (and harmonies); classical guitar is the only medium that makes use of its polyphony.

    Back to Mr. Dessner. As long as the electric guitar is just an adornment, a long sustaining hum, I don't see the point. The electric guitar could overpower the entire orchestra. So what are we offering? A quiet electric guitar? Electronic music and acoustic music don't really mix, or at least no one has found the key ... as far as Mr. Dessner's compositions I would only say, in the way that poets should probably not stray too far from music, music should not stray too far from dance ...

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  2. Thanks for the comment, Dex! I have to say that while I have been noticing Bryce Dessner more and more drifting into contemporary composition, I have not heard anything yet that really caught my attention and made me want to listen more. There are a lot of attempts to use the electric guitar in a classical context, this piece by Steve Reich for example:

    https://www.youtube.com/watch?v=wRN_jUrJSnE&t=1010s

    And there is that Spanish group that play Vivaldi concertos on electric guitars and pieces for large numbers of electric guitars by a couple of New York composers whose names I forget. On the whole, I suspect that the rock and blues roots of the guitar either are a hindrance or have not been successfully integrated or absorbed. Let's wait fifty years and see what happens!

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  3. I think the issue with electric guitar is the rather chaotic overtone structure of the amplified notes even when not grossly distorted. They sort of resemble bell overtones which themselves are rather immiscible with the orchestra. Also the sound is heavily dependent on both the instrument and the amplifier combination even without any signal processors. I really cannot see how amplified instruments can be successfully integrated into the conventional orchestra. Synthesizers on the other hand have some advantages since the sound envelope is programmable.

    The issue with the current orchestra is that it was created for 19th C tonal music and is not particularly well suited to either modal or atonal music IMO. The instrument families are very inhomogeneous apart from the strings.

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  4. Maury, I'm not sure I would describe the overtone structure of the electric guitar as "chaotic" exactly, though it certainly can be depending on the effects used. The fuzztone pedal, for example, makes for a very chaotic sound. There is a huge range of timbres available for the electric guitar. George Harrison often used a really bright, brilliant tone while Eric Clapton sometimes used a very mellow one without a lot of high partials.

    I had an interesting experience as a performer once. Donald Steven, at the time head of composition at McGill, wrote a piece for soprano and orchestra with an obbligato guitar part. The guitarist had to double on classical and electric guitar. For the occasion they had rented for me a Stratocaster and a big Marshall amp. The viola section looked rather apprehensive when I wheeled the latter up behind them. I have to say that I never got the volume control up above 1! No need to go to 11. At that level, a Marshall amp does not distort to any significant extent, so it is a "clean" sound. I didn't notice any difficulty blending with the orchestral sound. In fact, the orchestra has been expanding and absorbing such a host of new instruments that it is now rather a universe in itself.

    In the 18th century several wind instrument sections were added: flutes, oboes, trumpets and horns. The percussion section was pretty much limited to tympani, but Beethoven added some cymbals in the Turkish March of the 9th. Things really went wild in the 19th century with a lot of new low winds like the tuba, contrabassoons and a lot of percussion like snare drums, triangles, gongs and others. The 20th century has seen a riot of new instruments from the celeste and piano (both used in the 19th century as well), and a gazillion new percussion instruments. Messiaen even invented a couple. Then there was the Ondes martenot and the theremin, early electronic instruments.

    The core orchestra of the strings plus a few winds and percussion is still the core, but it has a lot of auxiliary wings now.

    Extra points for use of the word "immiscible."

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  5. Bryan,
    thanks for the recounting of your experience using the electric guitar. Yes I thought about hedging my statement exactly along the lines of how you used the instrument, but realistically it is very dicey. The choice of guitar, amp, use of plectrum and position of amp can all play a role in the sound. Also an amp tied to an open mic ie the guitar pickups can make little noises. In passing I would think a semi hollow body electric would produce a better tone for accompaniment than a Strat but I don't know if that was intentional on the composer's part or just unfamiliarity.

    Regarding the orchestra I am having trouble keeping my thoughts to a reasonable length so I'll just say to me the orchestral additions in the 20th C were mostly of the ear candy variety. It was in chamber music where more radical groupings were used for obvious economic reasons. Composers even as radical as Varese have been mostly forced into using the standard orchestra with extra percussion, and piano is used as percussion. The current economic situation for orchestras bodes ill however for more fundamental restructurings that are genre or style specific.

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