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This class is going to focus extensively on live examples, so the stuff on the class page is a little more scattered than usual; fear not, there are many toys to enjoy in class (and a boatload of YouTube videos for next week).

Slicing Up the Spectrum

We talked on the first day of class about the frequency spectrum (remember, 20Hz-20kHz?). Today, we’ll be looking at different ways of portioning out that audible spectrum.

The “job” of an instrument could be thought of as grouping together particular frequencies in a particular range and playing them at will. A grand piano, for example, typically can play notes from about 27Hz to 4186Hz. Within this chunk of the audible frequency, the keys quantize to a smaller set of frequencies. Quantization is the process of taking a continuous range (like the audible spectrum) and breaking it up into steps. On the piano, you can only play the notes that have keys, and there is no note between, say, B and C; contrast that with the violin, which lets you slide freely between notes and apply vibrato to individual notes. On a piano, the notes are discrete, while notes on the violin are continuous.

Another Look at Frequency

We’ll be looking at the sounds produced by a few different instruments in class via a spectrum analyzer. (Specifically, the “Spectrum” plugin in Ableton Live. A quick googling found this free program for macs that you could use if you were interested in exploring more.) Comparing the frequencies produced by a few different instruments on the spectrum analyzer, we will see evidence of…


Timbre is defined as the distinctive features of a sound other than pitch and loudness. The difference between a C played on the piano and the same C played on the violin is timbre. Looking at the spectrum analyzer, you can see that a note played on an instrument is never purely one frequency. Instruments produce a variety of harmonics and other sounds that contribute to their overall sound. So, in addition to delivering a particular range of frequencies quantized (or not) into particular steps, an instrument also collects together other frequencies that result from its specific features. On a violin, for example, the strings will emphasize certain harmonics in certain proportions, differently from the way a bassoon would; their shapes, the ways they are played, and the materials they are made of all affect these timbral sounds.

And, there is music made based on these differences! The German word for it is klangfarbenmelodie (“tone-color melody” in English). An instructive example is Anton Webern’s arrangement of a piece by Bach. The original music looks like this:

Webern’s arrangement takes this line that was originally to be played by one instrument and distributes it to a variety of instruments:

These example images are borrowed from the Wikipedia page on klangfarbenmelodie. Even if you can’t read music, you can see how the notes move from one line to another, maintaining the rhythm and pitches of the original, varying only in the timbre of the instruments. You can hear what this piece actually sounds like here.

Microtonal Music

The standard tonal system in Western music breaks up each octave into twelve tones (including the sharps and flats). A discrete instrument like the piano can only play these notes, but there are still frequencies in between these notes! A continuous instrument like the violin could play these notes, but in typical performance, aside from vibrato and the occasional slide, they are not used.

Microtonal music is music that uses intervals smaller than the standard Western semitone. There is not just one microtonal system, there are versions that have 19, 43, and a variety of other steps in the space of the traditional octave.

Harry Partch designed his own instruments that operate outside of traditional Western tonality:

and you can see and “play” some of them online here.

and some more instruments:

This is a “phonoharp” by Walter Kitundu. These instruments combine turntables and strings, to produce a variety of sounds.

Extended Techniques, Preparation

Some artists, instead of inventing new instruments, change the way they play their traditional instruments to produce new sounds. Ways of playing an instrument that are outside of the traditional playing style are known as extended techniques. Here is a clip of a duo called Nmperign playing a saxophone and trumpet using extended techniques.

And here are two clips of prepared piano which has had various items inserted among the strings, changing the way it sounds:

and this is the chart that specifies how the piano is to be prepared:

Musics Concrète and Elektronische

From Experimental Music by Michael Nyman:

“European composers broke though the ‘sound barrier’ into two, initially quite distinct, areas of electronic music: the French variety, musique concrète, which used sounds of an everyday acoustic or environmental origin, and elektronische Musik, the German brand which used only electronically generated sounds as its raw (or rather, smooth) material.”

We heard an example of musique concrète on the first day of class: the piece with the train sounds. Here is another piece by Pierre Schaeffer, the founder of that style:

or download here

and on the elektronische side of things, Karlheinz Stockhausen's Kontakte:

We will also talk a little bit about synthesis.


some bonus vids

If you have any questions or comments,
you can email me at seaver[shift-2]mit.edu or comment below.