Helmholtz air resonance of the cello and baritone
Carleen Maley Hutchins · The Journal of the Acoustical Society of America · 1980
The so-called Helmholtz air resonance of the cello lies approximately an octave below its main wood resonance. This relationship causes the frequency range of the Helmholtz resonance to be extremely powerful because of second harmonic reinforcement when bowing. The original concept for the new violin family instruments (NVF) was to have these two main resonances in each instrument near the frequency of its two open middle strings, about a musical fifth apart. In designing the large cello, baritone of the NVF, it was found that musicians, accustomed to the power and tone quality of the cello's low C string range, liked the baritone when its Helmholtz resonance was more than the fifth below its main wood resonance. However, in the musical evaluation of the NVF at the Royal College of Music, London, the low C string range of the baritone seemed to overbalance the other instruments, particularly the higher ones. Therefore a baritone with shallower ribs was built with its Helmholtz resonance at 89 Hz and its main wood resonance at 157 Hz. Construction parameters and musical evaluation of these instruments will be discussed.