Four bars of Mozart explains everything humans like in music

I’m not arguing here that everyone loves Mozart, or that I’m about to explain what all humans enjoy all the time. But I can say with confidence that this little bit of Mozart goes a long way toward explaining what most humans enjoy most of the time. The four bars I’m talking about are these, from “Eine Kleine Nachtmusik.”

What these four bars of music demonstrate is that humans like:

  1. Repetition
  2. Breaks in the repetition
  3. Repetition of the breaks in the repetition
  4. Breaks in the repetition of the breaks in the repetition
  5. Recursive layers of patterns of breaks and repetitions

In order to prove this to you, I’m going to talk you through these eighteen notes one at a time.

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The Vocoder, Auto-Tune, Pitch Standardization and Vocal Virtuosity

Writing assignment for History of Science and Technology class with Myles Jackson. See a more informal introduction to the vocoder here.

Casual music listeners know the vocoder best as the robotic voice effect popular in disco and early hip-hop. Anyone who has heard pop music of the last two decades has heard Auto-Tune. The two effects are frequently mistaken for one another, and for good reason—they share the same mathematical and technological basis. Auto-Tune has become ubiquitous in recording studios, in two very different incarnations. There is its intended use, as an expedient way to correct out-of-tune notes, replacing various tedious and labor-intensive manual methods. Pop, hip-hop and electronic dance music producers have also found an unintended use for Auto-Tune, as a special effect that quantizes pitches to a conspicuously excessive degree, giving the voice a synthetic, otherworldly quality. In this paper, I discuss the history of the vocoder and Auto-Tune, in the context of broader efforts to use science and technology to mathematically analyze and standardize music. I also explore how such technologies problematize our ideas of virtuosity.

Ableton vocoder

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The vocoder and Auto-Tune

This post documents a presentation I’m giving in my History of Science and Technology class with Myles Jackson. See also a more formal history of the vocoder.

The vocoder is one of those mysterious technologies that’s far more widely used than understood. Here I explain what it is, how it works, and why you should care. A casual music listener knows the vocoder best as a way to make that robot voice effect that Daft Punk uses all the time.

Here’s Huston Singletary demonstrating the vocoder in Ableton Live.

This is a nifty effect, but why should you care? For one thing, you use this technology every time you talk on your cell phone. For another, this effect gave rise to Auto-Tune, which, love it or hate it, is the defining sound of contemporary popular music. Let’s dive in!

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What the heck is the LIGO chirp?

I recently posted a track on SoundCloud that included the sonification of LIGO’s gravitational wave data. A student asked me what that meant. Since today is Albert Einstein’s birthday, what better time to try to formulate an answer?

First, some context: 1.3 billion years ago, two black holes collided. Each was about thirty times as heavy as the sun. The collision took a tenth of a second and released fifty times more energy than all the stars in the observable universe. Here’s how it looked:

Black holes collide

Of course, black holes being black, you can’t see them; the graphic shows the way that they would warp the appearance of stars behind them.

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Defining harmonic relatedness

Linear music notation is good for reading, but it doesn’t tell you everything you want to know about underlying musical structure. Notes that are close to each vertically are not necessarily the most closely related. The concept of harmonic relatedness is a complex one, but there’s an excellent tool for beginning to get a handle on it: the circle of fifths.

The chromatic circle and the circle of fifths

The left circle above shows the chromatic circle, the pitch sequence you find on the piano. The right circle shows the circle of fifths. Each note is a fifth higher or a fourth lower than its counterclockwise neighbor, and each note is also a fourth higher or a fifth lower than its clockwise neighbor.

Unlike a lot of music theory you learn in school, the circle of fifths is not some arbitrary Western European cultural convention. There’s actual science behind it. If two notes are adjacent on the circle of fifths, it means they have a lot of overtones in common. If you know what overtones are, you can skip the next few paragraphs. Otherwise, read on.

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Digital audio basics

Before you can understand how digital audio works, you need to know a few things about the physics of sound. This animation shows a sound wave emanating through the air from a circular source — imagine that it’s a drum or cymbal.

Spherical pressure waves

As you can see, sound is a wave, like a ripple in a pond. Imagine that your ear is at the bottom center of this image. The air pressure against your inner ear is rhythmically increasing and decreasing. Your brain senses how wide those swings in air pressure are and how often they’re happening, and you experience the result as a sound.

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Can science make a better music theory?

My last post discussed how we should be deriving music theory from empirical observation of what people like using ethnomusicology. Another good strategy would be to derive music theory from observation of what’s going on between our ears. Daniel Shawcross Wilkerson has attempted just that in his essay, Harmony Explained: Progress Towards A Scientific Theory of Music. The essay has an endearingly old-timey subtitle:

The Major Scale, The Standard Chord Dictionary, and The Difference of Feeling Between The Major and Minor Triads Explained from the First Principles of Physics and Computation; The Theory of Helmholtz Shown To Be Incomplete and The Theory of Terhardt and Some Others Considered

Wilkerson begins with the observation that music theory books read like medical texts from the middle ages: “they contain unjustified superstition, non-reasoning, and funny symbols glorified by Latin phrases.” We can do better.

Standing waves on a string

Wilkerson proposes that we derive a theory of harmony from first principles drawn from our understanding of how the brain processes audio signals. We evolved to be able to detect sounds with natural harmonics, because those usually come from significant sources, like the throats of other animals. Musical harmony is our way of gratifying our harmonic-series detectors.

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Toward a better music theory

Update: a version of this post appeared on Slate.com.

I seem to have touched a nerve with my rant about the conventional teaching of music theory and how poorly it serves practicing musicians. I thought it would be a good idea to follow that up with some ideas for how to make music theory more useful and relevant.

The goal of music theory should be to explain common practice music. I don’t mean “common practice” in its present pedagogical sense. I mean the musical practices that are most prevalent in a given time and place, like America in 2013. Rather than trying to identify a canonical body of works and a bounded set of rules defined by that canon, we should take an ethnomusicological approach. We should be asking: what is it that musicians are doing that sounds good? What patterns can we detect in the broad mass of music being made and enjoyed out there in the world?

I have my own set of ideas about what constitutes common practice music in America in 2013, but I also come with my set of biases and preferences. It would be better to have some hard data on what we all collectively think makes for valid music. Trevor de Clerq and David Temperley have bravely attempted to build just such a data set, at least within one specific area: the harmonic practices used in rock, as defined by Rolling Stone magazine’s list of the 500 Greatest Songs of All Time. Temperley and de Clerq transcribed the top 20 songs from each decade between 1950 and 2000. You can see the results in their paper, “A corpus analysis of rock harmony.” They also have a web site where you can download their raw data and analyze it yourself. The whole project is a masterpiece of descriptivist music theory, as opposed to the bad prescriptivist kind.

Jimi Hendrix, common practice musician

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Music theory and quantum mechanics

In high school science class, you probably saw a picture of an atom that looked like this:

Stylized Bohr atom

The picture shows a stylized nucleus with red protons and blue neutrons, surrounded by three grey electrons. It’s an attractive and iconic image. It makes a nice logo. Unfortunately, it’s also totally wrong. There’s an extent to which subatomic particles are like little marbles, but it’s a limited extent. Electrons do move around the nucleus, but they don’t do it in elliptical paths as if they’re little moons orbiting a planet. The true nature of electrons in atoms is way weirder and cooler.

Pictures are a terrible way to understand the nature of quantum particles. Music theory is much better.

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