Latin American Electroacoustic Music Collection

Manuel Rocha Iturbide, Frost clear, 1991
[Frost clear energy saver]

Recording time: 17 min 18 s.
Instruments: Electroacoustic composition for refrigerator, double bass and digital tape

Other resources available:
- About Manuel Rocha Iturbide
- Compositions by Manuel Rocha Iturbide

About this composition:

For: Digital tape, double bass, amplified refrigerator.

Technique: The sounds of the piece were analyzed in computer by FFT and transformed with digital audio software Turbosynth and Sound designer (Digidesign). They were mixed down in a 24 track studio at the Center of Contemporary Music of Mills College.

By unfolding a sound object, I am trying to show different perspectives of one same sound. Metaphorically, this could be equivalent to visualizing a sound in three dimensions, being able in this way to perceive its different characteristics. This is like walking around a sculpture in a museum. It changes every time, but in fact it is always the same sculpture. I used this idea in "Frost Clear energy saver", which is made from digital manipulation of a sample recorded from the motor of my refrigerator. Now, why did I ever think about making music with such a sound?. I used to hate refrigerator sounds because every time I was near one of them, I felt bothered without knowing why. Suddenly, when the refrigerator motor stopped, I realized that my problem had originated from its intermittent sound. It wasn't until later in Oakland California that I discovered that refrigerators could make interesting sounds. The sound of my refrigerator's motor seemed to be like a singing voice because the overtones changed constantly and regularly, and by listening carefully I discovered that the spectral structure of the sound was very rich due to the combination of natural harmonics and inharmonics. There was also a fundamental "hum", as there is a fundamental note for a chord structure. The micro-spectral changes of the refrigerator are generally unnoticed in daily life because in order to listen to them we have to get very near the motor, or to amplify it. I tried then to use the refrigerator's motor sound structure in a composition, in order to discover its richness. To accomplish this, I created different sounds by manipulating a refrigerator sample which I recorded with a contact microphone. Every sound was transformed by reverberating a different portion of the original sound's spectrum (digital reverberation band-filters), then they were mixed down, having as a result a continuous process where we could listen to the whole spectrum being unfolded through time. As this process is texture-like and has no gesture, we make an effort to distinguish it's different components and listen with care to all the micro modulations taking place. As a result, this listening attitude allows us to find the hidden qualities in the motor sound which in real life seemed to be just an uniform and static noise. Using digital sound technology was fundamental to accomplish this, in order to analyze and transform the sound spectrum with detailed accuracy. To reinforce the idea of listening to the spectral change of one sound object, I introduced a live double bass to the piece that only plays its low open string tuned to the same pitch as the refrigerator "hum". The double bass has instructions to play on different parts of the string, so when the refrigerator overtones are high, the performer plays "sul ponticello" in order to bring out high overtones as well. In this way there is an analogous continuous transformation of timbre in the double bass sound that follows the process of the refrigerators spectrum and which interacts with it, creating in this way other inharmonic sounds.

In the second section of the piece I introduce a new element which is a transformation of the original sound object, but which breaks with its essence. I bring up discontinuity by fragmenting the different transformed sounds of the beginning, and creating melodies extracted from the frequencies of the original overtones. The shape of the first melodies are constructed with the frequencies of the natural harmonics belonging to the spectrum. Later on, I introduce melodies made out from the inharmonic portion of it, so they become dissonant in relation to the first ones. At the same time, the long sounds from the beginning continue, but new ones appear in the register of the refrigerator's highest overtones, becoming almost sinusoidal and very piercing to the ear. By fragmenting and using the original sound as musical notes in this section, I render it unreal and artificial. My intention was to create note sequences that resemble to the LFO function of a synthesizer, and which make us imagine a machine that is going crazy. You can see how by changing the morphology of the original sound I also changed its signification and was able to create a metaphor with which I described a sort of travel into the refrigerator's entrails, playing in this way with the idea of machines as being dangerous living entities".