What the heck is a decibel

If you are a musician or audio engineer, it is very important to know what decibels are. Unfortunately, decibels are extremely confusing. For one thing, there are so many different kinds of decibels! You only care about two of them: the decibels you see on a noise meter, and the decibels you see on a mixer. The decibel scale is meant to reflect the subjective experience of your hearing. A change of one decibel is a just noticeable difference: if you make something one decibel louder, that is just enough for the listener to notice that it’s louder. Makes sense, right? Unfortunately, decibels are logarithmic, which makes it hard to develop an intuition for the actual sound pressure levels that they represent. Let’s dig in.

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The whole tone scale

Like diminished chords, the whole tone scale is not very widely used, but when you need that specific vibe, nothing else will do. Whole tone scales are easy to understand, because there are only two of them total. Whichever key you are in, there is a whole tone scale that includes the tonic, and another one that doesn’t. I have never seen a useful naming system for these two scales, so I call them yin and yang.

Notice that the notes not found in yin are all the notes in yang, and vice versa. Another fun thing is that when you write the whole tone scales on the circle of fifths, they look exactly the same as they do on the chromatic circle – all the yang scale tones just switch places with their counterparts a tritone away. Symmetry! Continue reading

The chromatic circle and the circle of fifths

The heart of Western tonal theory is this diagram:

It’s called the chromatic circle, and it shows all of the notes you can play with a piano keyboard or guitar fretboard. It is closely related to another extremely important diagram called the circle of fifths:

In this post, I explain where these diagrams come from and what they mean.

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Seventh chords in just intonation vs 12-TET

I enjoy listening to Jacob Collier explain his music more than I enjoy the music itself. His arrangement of “Moon River” is mostly exhausting. However, Miles Comiskey pointed me to an interesting moment in this explainer video at the 1:04:22 mark where Jacob talks about how Kontakt enables you to change your instrument tuning on the fly.

Jacob takes a dominant seventh chord and plays it in two different tuning systems: twelve-tone equal temperament, the system we’re all used to, and just intonation, which is a more “pure” harmonics-based system. The chord sounds very different in the two systems. That is a profound musical concept that is not easy to understand! Jacob buries it in his song under five thousand other ideas, but I thought it would be helpful if I built a whole track around it:

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The blues and the harmonic series – a visual guide

Does the harmony of the blues come from the natural overtone series? Is it a just intonation system that later got shoehorned into Western twelve-tone equal temperament?

Whether the blues comes from just intonation, or just intonation happens to sound like the blues, this is a rich and promising avenue of inquiry, both for understanding the blues and for creating new music inspired by it. In this post, I use MTS-ESP, Oddsound’s amazing microtonal tuning plugin, to visualize the possible harmonic basis of the blues. Continue reading

The problem with just intonation – a visual guide

Tuning is the final frontier of my musical understanding. I start reading about it, and then I hit a big table of fractions or logarithms and my eyes immediately glaze over. However, tuning is important and interesting! So I continue to struggle on. Fortunately, as with so many music theory concepts, the right computer software can open up lots of new learning avenues. I have been having a great time with MTS-ESP by Oddsound. It was designed to help you hear and play different tuning systems, but it also visualizes them in an attractive circular way. If you read this blog, you know how much I love a good circular music visualization scheme.

So here is the basic problem with tuning. An ideal system (for Western people) would be based on the natural harmonic series, because we love how harmonics sound. This kind of tuning system is called just intonation. It sounds lovely! Unfortunately, just intonation makes it impossible to change keys or tune your guitar. Let’s use MTS-ESP to figure out why that is. Continue reading

Just intonation and key changes

Western people like two things in harmony: intervals derived from the natural overtone series, and the ability to play in multiple keys. Unfortunately, it’s not possible to do both of these things within the same tuning system. If you want to use just intonation intervals derived from harmonics, then they will not work in every key. So we as a civilization have decided to use a tuning system that enables you to play in lots of different keys, even though it means that all of the keys are slightly out of tune. Fortunately, the computer makes it easy to explore alternative tuning systems. I have been experimenting with this cool tuning plugin called MTS-ESP.

I have struggled my whole life to understand how tuning works, so I made a track to demonstrate to myself how just intonation sounds when you use it in all twelve keys.

What you are hearing in my track is a tuning system that is “perfect” in C major, but not so perfect in other keys, and very not perfect in a few of them. Let’s figure out why!

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The blues and the harmonic series

In this post, I’m going to expand on an idea in my blues tonality treatise: that the distinctive scales and chords of the blues are an approximation of African-descended tuning systems based on the natural overtone series. Gerhard Kubik argues in his book Africa and the Blues that blues tonality comes from the overtone series of I and IV, and can only be approximated using instruments tuned to standard twelve-tone equal temperament (12-TET). Let’s unpack what that means!

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Circular chord charts

Being home with my kids all day is not very conducive to dissertation writing, but my fragmented attention is still up to the task of making infographics. I’ve been thinking about ways of visually representing grooves. Since circles work so well for rhythms, maybe they can work for harmonies too. Here’s a circular view of twelve bar blues in C:

Think of this as a chord chart wrapped in a circle rather than written in a line. Each cell is a measure. Start on the C7 at the top and move clockwise.

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