Tubular bells - A comparison between bells and tubular bells (chimes)
Characteristics of the structure and perception of the bell sound
As with all idiophones the sound of bells consists of two components: the strike note (attack) and the resonance. The composition of the sound of ”real” (i.e. church) bells is especially complicated. It consists of a mixture of a great many individual tones that sound at different pitches and different volumes and resonate for different lengths of time; in other words, it is a tone mixture. Many of these individual tones (partials) are inharmonic, i.e. they are not in a whole number ratio to the fundamental. The ear perceives them as a fluctuating sound, in other words, it has problems picking out a definite pitch from the various different sounds it hears. To compound matters, the intensity of the overtones can far exceed that of the fundamental pitch.
In our perception of ringing bells, two different impressions predominate: the strike note (attack), a short, forceful, metallic sound at a single pitch; and the resonance, long, resounding tones at various pitches (the fundamental). The pitch of the bell is determined by the strike note, which lies an octave above the fundamental. Along with the major or minor third it is the fundamental that dominates the resounding note as it is perceived. It is for this reason that we speak of minor third or major third bells. Minor third bells are more common.
In contrast, the perceived pitch of a musical instrument is clearly identifiable and usually corresponds to the frequency of the lowest (1st) partial.
Strictly speaking, then, bells occupy a position somewhere between percussion instruments with definite pitch and those with indefinite pitch.
Tubular bells share only some of the sound characteristics of bells and the structure of their sound differs from that of church bells on which they were modeled. These differences are due to the fact that tubular bells have always been made to meet musical requirements as well. Their manufacture pursued one of two main aims: either to duplicate the richness of overtones of church bells, or to make tubes with a clear pitch in the musical sense. The latter aim proved the more popular since it served to establish the chimes as an orchestral instrument in their own right.
One of the main differences between the way bells and chimes are made is the fact that the top and bottom of the latter are identical. This favors a relatively harmonic structure of partials which is suitable for musical purposes and aids combinations with other orchestra instruments. Church bells contain a large number of inharmonic partials.
Strike note and resonance
The strike note is a short, forceful, metallic sound impression at a single pitch, an octave above the fundamental; the resonance is a long, resounding note rich in overtones which is dominated by two pitches, the strike note and the fundamental, which sounds an octave lower. This has led to disagreement on which octave tubular bells are really in. Some people contend that the resonance (which is an octave lower than the strike note) is the actual pitch. However, studies have shown that the strike note (an octave above the fundamental of the resounding note) is the actual pitch. The pitches of the strike notes, which are those written in the score, therefore range from C4 to F5, or from F3 to F5 on a two-octave instrument.
Like all metal idiophones (metallophones) tubular bells’ notes decay only slowly, in other words their resonance is relatively long.
Unlike (church) bells, the resonance of which is dominated by the third, tubular bells are made so that the fifth (above the strike note) is also audible beside the fundamental (an octave below the strike note). This makes the instrument more suitable for playing together with other musical instruments.