Pieces of foam may be wedged in between the strings and the fingerboard of bowed string instruments, altering the pitch and timbre of the strings. When wedged at harmonic nodes, the foam may activate the nodes, making otherwise impossible hand positions available.
It is possible that this preparation has been explored on modern string instruments in 21st-century repertoire and experimental improvisation.
Foam on the baroque violin:
Foam preparations function well as a means of altering the timbre of the baroque violin, as the gut strings require little interference in order to distort. If a foam preparation is being used at harmonic node points, extra care must be taken to find the exact placement, which elicits the clearest tone. This can potentially vary slightly from string to string, especially between the thickest raw-gut D string and the adjacent metal-wound G string.
The following is an example of foam preparations on the baroque violin both on open strings and with stopped options.
Video example 27.1 – foam preparation
Figure 27.1 – foam preparation under the strings of baroque violin
The following is an example of foam preparations in an excerpt from the violin part of Curious Animals by Paddy Mann (2016, p. 1).
Video example 27.2 – foam preparation in violin part of Curious Animals by Paddy Mann (2016, p. 1), bars 1–2
Figure 27.2 – foam preparation notation in violin part of Curious Animals by Paddy Mann (2016, p. 1), bars 1–2
A text box above the stave, including “Foam on”, and “Foam off” to indicate passages which should have the preparation applied, as in Figure 27.2 above.