Section 1 - Understanding Pitch and Chroma
Pitch is a measurement of frequency that is more specifically referred to in the audible range of the electromagnetic spectrum. This range is most often measured in vibrations per second, or Hertz (Hz). The human range of hearing spans from 15 Hz to 18,000 Hz on average. This is in comparison to human vision, which ranges from approximately 375,000,000,000,000 Hz to 750,000,000,000,000 Hz.
Due to the extremely high frequencies in the visual spectrum, it is more often measured in nanometers of light wavelengths or nm. By converting Hz to nm, the visual range would fall between 800nm to 400nm in wavelength. The distance between wavelengths become closer as the speed of the vibrations increase towards the upper range; thus the smaller number of nm.
Wide as the visual range is, the upper response range is still roughly double the frequency of the lower. This almost makes the entire visual range one "octave" of the electromagnetic spectrum. The visible light in the spectrum breaks up into different colors that blend into each other (Fig. 1.1). At the low end, infrared turns into red. At the high end it looks almost as if violet is about to turn back into red, but instead it turns into ultraviolet which is invisible.
Figure 1.1 - Visual Spectrum Range
In contrast to the visual range, the hearing range has several intervals where the frequencies of pitch can double. In musical context these are called octaves. When listened to, these divisible intervals present a definite similarity in pitch pattern. For example, take the concert pitch A at 440 Hz and get another audible A at 880 Hz. Double it thirty-nine more times and, the frequency of A would be 483,785,116,220,000 Hz. Far out of our audible range that A harmonic would be a light frequency seen close to yellow.
Helmholtz transposed musical frequencies in this fashion in order to find relationships between visual colors and musical notes (Fig. 1.2). It remains never necessary to think of musical notes represented as visual colors when learning them; they each manifest as separate perceptions. Thus, no formal connection can be made between the senses in this regard, although it makes a great example of how both pitch chroma and visual colors are recognized by their differences
Figure 1.2 - Visual Spectrum with Transposed Musical Notes
Individuals are subject to personal interpretations of any chroma, be it sound or light. This results in the impossibility of describing a pitch’s chroma. Attempts have been made to describe the pitch 'A' as being bright or 'Eb' as being dark, but you can similarly describe them as happy and mellow. It would be difficult to describe the color of red to individuals who have never seen any color. Hints can be given by relating the color to commonly known examples of red, but this would mean very little to the subject who can not relate these events. The slight alteration in perception from one color to the next results in the successful naming of them.
Individuals who do perceive visual colors, might experience green slightly different from another person’s perception of that same color. In either case they would have learned to name their own perceptions to a similar label. A person could be raised calling the current classification of "red", something else like "blue", and it would not stop them from identifying it consistently. The fact that all of us identify our perceptions of color similarly makes us take much of common understanding for granted. For example, it would sound strange to us when we describe a car as being the color "red" when this other hypothetical person would describe that same car as the color "blue". Luckily the people who raised us were never that cruel.
Similarly, the perceptual differences among aural pitches are necessary in order to begin understanding their nature. The names we give musical chroma are not relevant to learning them. You can identify one pitch from another by learning the pattern similarities and differences between them. Each one of these "chroma", will always have the same pattern each time we hear them and the recognition of these chroma patterns will become clearer by constantly comparing them to one another. The individual needs to experience the perception of chroma for themselves in order to identify them.
Another beneficial effect of comparing pitches to one another is being able to recognize the interval between them. Many times this is referred to as relative pitch. Relative pitch perception has a more obvious effect in the human’s awareness. Whenever music is listened to, some sense of relative pitch is needed. The relationships in the sound give the idea of harmony and melody. Harmony is based on the distance between pitches, and melody is harmony perceived through time.
The sound itself is made up of pitch chroma, tone colors (attack and decay), and volume. The tone colors are qualities of sound that give away what the sound exactly is, like a "voice", "flute", or "truck". Volume entails the amount of amplification or how "loud" or "quiet" the sound is. In this application, pitch chroma is the main concern. Pitch is inside tone color and volume, and is often described as musical qualities like "high" or "low". As long as pitch is not distorted too much by tone color and volume, humans are able to distinguish between them.
ProLobe has a prearranged system of tests that will guide the ear towards chroma hearing. The use of relative pitch in the aid of completing this program will definitely benefit the ear in a relative way. However, using relative pitch or the interval between notes to calculate the correct answer will not aid in the development of chroma identification skills. You must focus on the pitch chroma to develop Perfect Pitch. The exact procedures in using the program are described later in sections 3, 4, and 5.