On July 4th at Ircam in Paris, during the July 2010 Prisma meeting, I included in my presentation a few sonograms of clarinet "multiphonic" sounds, these sounds in which one can hear more than one pitch at the same time.
Sonograms
I recorded these rough multiphonic clarinet sounds in Cambridge on Friday, June 19th, 2010. The four sound files are available on freesound: Clarinet multiphonics.
bb-clarinet-01-split.aif
This is the sonogram of a rich multiphonic sound, commonly called a split tone. Here, it's played on a low fingered E (concert D), the lowest note of the Bb clarinet. The clarinet player can emphasize different harmonic regions. This is what Iannis Xenakis is calling for in his 1971 composition Charisma for clarinet and cello, when he writes Harm. Zone I, II, III, and IV. To achieve this effect, the clarinet player modulates the air pressure and changes the shape of his/her vocal cavities. We see on the sonogram that this selective reinforcement of harmonic regions consists in moving two formants.
bb-clarinet-02-isolate.aif
This second sonogram shows that on the same low E fingering, the clarinetist can choose which partials sound. This is the basic technique for producing notes in different registers. In normal clarinet playing, the selection of the register is done with the help of keys and fingerings, but the control of the air column and vocal track shape remains very important.
bb-clarinet-03-series.aif
By using special fingerings, one can transform a unique clarinet into a dual sound generator. E. Michael Richards explains the phenomenon very well. The sonogram above corresponds to the example #2 on his page Clarinet multiple sounds - you'll find there the score and fingerings.
bb-clarinet-04-octave.aif
As you may know, the clarinet's bore is mostly cylindrical, and that results in very weak even harmonics in the sound. For instance, the octave is almost absent from the analysis of a clarinet sound. But if you find a special multiphonic fingering giving you a fundamental and its octave, you can really change the timbre of the instrument. The last sonogram illustrates such a sound, here with a fade from a note to its octave.
Clarinet acoustics
Here are a few good sources on the acoustics of the clarinet.
And let me introduce two friends of mine. First, the excellent Michael Norsworthy, Boston-based clarinetist. In the following video, he demonstrates four types of multiphonics. By the way, he calls "overblowing" multiphonics the ones I call split tones.
Prisma stands for International Pedagogy and Research on Assisted Musical Systems. This summer, this group of composers, musicians, and software developers is meeting from July 2nd to 5th at Ircam in Paris.
Last year, my talk was entitled Ableton Live for Live Electronics. I compared Ableton Live to Max 5, highlighting what was easier to realize using one or the other piece of software, in the context of composing for classical instruments and live electronic music. I also talked about Logic Pro, since most of the "live electronic music" capabilities used by many composers are also implemented inside Logic Pro's environment.
This year, I'm going to present several dimensions of the Harvard course The Physics of Music & Sound:
Max 5 patches I developed for the course a generator of partials, a model of a siren, and an application to play with and understand better formants
Inharmonicity of low piano strings a homework assignment in which students have to determine which piano is the biggest through a spectral analysis of low note samples
Clarinet multiphonics I've been working on a new homework assignment studying clarinet multiphonic and subtone sounds. I'll give a glimpse of that work-in-progress.