The Capo Elevator is a product that has developed out of a research project to improve the sustain of an acoustic guitar when using a capo.
The key premise was to try to recover some of the ringing openness of the open strings from when playing at the nut. The project focused on interventions for fingerpicked steel strung acoustic guitar.
The following challenges of existing capo designs were identified:
Most capos use a fret as a substitute for the nut. This kind of set-up can be excellent for intonation accuracy, as exemplified by Brian May’s preferred ‘zero fret’ approach. However, for finger picked arpeggios on the open strings of an acoustic instrument, they have less ‘ring’.
Many capo designs are not shaped to match the radius of the fingerboard very accurately. There have been some very welcome developments in this area, with manufacturers providing inserts for the capo arm, or complex compensation mechanisms. But these are the exception.
The use of plastics and rubber in capo design. Whilst it is accepted that rubber is very important for the protection of the instrument, and has been used to make up for inaccuracies referred to in the previous point, it is not a sonorous material and can deaden the sound.
The use of rubber was avoided when exploring design options for the reasons described above. The study focussed on the potential of sonorous materials. Hardwood handmade prototypes were developed into accurately profiled machine-cut metal parts. These were designed to sit over the fret to raise the action, and to follow the radius of the fretboard.
Designs were developed to work alongside existing capo types – it was decided that it was unnecessary to replicate the work that had gone into the development of existing clamping and binding mechanisms, many of which were already very good, and some of which were patented. Thus, the design became a device that works in conjunction with existing capo types.
Playing and listening tests identified that the prototype could be held in place by a capo’s clamping mechanism which was mounted either partially over the top of the fret, or further up the fretboard from the fret. The latter resulted in slightly less body to the sound, perhaps because the prototype wasn’t tightly bound to the fret. However, the subjective impression was that the ringing of the open strings had improved. A comparison video has been made to demonstrate this.
A slide handle was designed to prevent the metal part from falling between the strings and the fretboard when the pressure of the capo was removed. It was decided that the handle would be removable to allow the full width of the metal part to be utilised to accommodate wide fretboard widths. A simple handle was designed to avoid the possibility of rattle from more complex parts.