Chime
The strike note is a perceived pitch impression. It is used to designate the pitch of a bell , which is why the newer term nominal or nominal tone is increasingly used in campanology .
In the sound spectrum of a bell, the strike tone is usually not present as a physically measurable individual frequency, but is formed by the human ear from the harmony of those partials of a bell that correspond to the overtone series ( residual tone ).
Naming of the partials
In campanology , the naming of partials after today's standard bell , the pure octave bell , has established itself. Starting from the lowest partial tone, the undertone (one octave below the strike note in the case of the octave bell), the higher partials follow, which are designated by the name of the interval by which they are above the strike note:
This terminology is retained with old bells, although some of the partials do not correspond to the interval that characterizes them. For example, the fifth can be deepened to the fourth , or the prime can deviate from the strike note by up to a whole tone . Tolerance limits for these deviations in new bells are defined in the Limburg guidelines of 1951, an agreement between the Advisory Committee for the German Bell System and the Association of German Bell Founders .
The typical deviations for bells from the tones of the equally tempered tuning are given in sixteenths of a semitone . The reference tone is a 1 = 435 Hz .
Overtone series
Only those partials of the bell, the frequencies of which form roughly an overtone series from integer multiples of a non-existent, only aurally detectable fundamental tone , i.e .:
contribute to the formation of the striking note as precisely this fundamental note. They are also known as beat tone builders.
The frequency ratios of the overtones do not have to be very exact in order to form a clearly pronounced strike tone. However, if they are too much out of tune with one another, such as B. with some beehive and sugar loaf bells , no clear sound is heard.
Striking sound with small bells
In the case of very small bells, the partial tones that otherwise form a striking tone are in a frequency range for which the hearing is less sensitive, while the lowest partials are in a more favorable range and are easier to hear. For small bells, therefore, a strike note consisting of undertone , prime and octave is perceived that is in the range of the undertone, i.e. about an octave lower than usual.
Striking sound for large bells
Secondary tones are also residual tones, which are formed from other partial tones of the bell.
The most important of these is the fourth minor note , which is about a fourth above the strike note, sometimes only about a major third . It is formed from the partials
- Undezime (double frequency)
- Double octave (triple frequency) as well
- further higher partials.
This sidelong occurs particularly with large and deep bells, as the high partials that contribute to the formation of residuals lie in a frequency range to which the hearing is particularly sensitive.
calculation
The striking tone calculation according to JF Schouten is now considered obsolete because it does not take into account the partial tone amplitudes or the physiology of the human ear . As a first approximation, however, the strike note is almost always - with the exception of very small bells - at octave intervals below the octave partial tone (Rayleigh's rule) .
See also
literature
- Gothard Bruhn: About the audibility of bell tones. Bosse, Regensburg 1980.
- William A. Hibbert: The Quantification of Strike Pitch and Pitch Shifts in Church Bells. (Dissertation), 2008. ( online )
- André Lehr: De betekenis van de duodeciem voor de vorming van de slagtoon. ( online ( Memento from November 1, 2007 in the Internet Archive ))
Web links
- Special features in the sound structure and in the perception of bell sounds ( memento from March 13, 2007 in the Internet Archive )
Individual evidence
- ^ A b Claus Peter: Bells, chimes and tower clocks in Bamberg . Heinrichs-Verlag, Bamberg 2008, p. 351.
- ^ Limburg guidelines for the sound assessment of new bells , Limburg 1951. Reproduced in: Kurt Kramer , Advisory Committee for the German Bell System (ed.): Bells in history and present. Contributions to bells , vol. 1. Badenia-Verlag, Karlsruhe 1986.
- ^ Gerhard D. Wagner: The strike tone calculation after Schouten . In: Kurt Kramer , Advisory Committee for the German Bell System (Hrsg.): Bells in past and present. Contributions to bells , vol. 1. Badenia-Verlag, Karlsruhe 1986.
- ↑ a b c Jörg Wernisch: Bell customer of Austria . Journal-Verlag, Lienz 2006.