leescottnewcombe

 

The Diapason

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Taking its name from the definition of the word meaning ‘a grand swelling burst of harmony’, it is an instrument that is an exemplar of the full range of psychoacoustic properties the 53-tone JI scale has to offer, as well as being the most suitable sound source to tune other instruments if necessary.

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The diapason is a unique instrument made from musical glasses that are configured to be sounded in two separate ways; either using the stick-slip technique of a moistened finger circling the rim, whereby the finger, when moving over the surface, encounters resistance, whilst the water counteracts that resistance allowing the finger to slide which sounds the resonant tone of the glass that can be sustained for an indefinite period of time; or struck by a semi-soft mallet or light stick approximately two centimetres below the rim, creating a percussed ‘bell-like’ timbre with a decay length dependent on the quality of glass.

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It is a variation on the design of a glass harp, but instead of fixing glasses onto a horizontal board, they are suspendedvertically with the use of clamps. This arrangement allows for the optimum accessibility to all notes whether they aresounded with the stick-slip or percussed techniques.

 

The two manufactured designs of glass that are most suitable for the instrument, due to their stem and larger size, are brandy and wine glasses. To achieve the optimum results when sounding, it is best if these designs are blown using quartzglass which allows for a clearer quality of tone and an elongated decay. To tune glasses that resonate at a frequency outside of the scale you add water to lower the pitch until you reach the desired note. The pitch range frequencies on the diapason currently commence with the fundamental G4 - 1/1 (392 Hz) ascending to the octave doubling G5 - 2/1 (783.99Hz), although this octave range can be varied by changing the glasses used. Each individual glass has its corresponding note name written on colour coded paper securely taped to the base of the glass. This aids the navigation of the instrument when performing.

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The instrument has four manuals, each constructed in a uniform manner. The stands are Yamaha CS865 boom cymbal stands, selected for their sturdy double-braced legs and step-free tilter system which allows for the attachment of a 1.5cm diameter steel rod that can be configured horizontally. Three heavy duty boss head clamps are secured to the steel rod to facilitate three vertical steel rods that create a trident formation. To these are attached light-weight boss head clamps that fix the three-pronged clamps into place, tightly grasping the stems of the glasses. Attached to the stands are percussion trays suitable for placing water bowls and/or beaters in an accessible position for performers. Finally, a clip-on musicstand is attached above the percussion tray for performers to read the score.

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Having four independent manuals allows the diapason to be set-up in multiple spatial arrangements. Configurations include a linear or arc formation. These are necessary when a piece requires the performers to sound notes that fall outside of their assigned manual simultaneously with their own. If the performer’s score features only notes within their assigned manual it can be configured as a square or spatialized to remote locations within the performance environment.

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The manuals can be adjusted and varied to suit each individual performers own height, allowing all the notes to be easily accessible. It also facilitates the performers being able to stand when playing or seated on stools.

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The configuration of notes on the diapason are modular. They can be individually moved and placed in unique formations depending on the requirements of each work. Unlike conventional instruments, having a chromatic layout would prove impractical for the performers. The works written for these instruments aim to exploit the psychoacoustic nature of close tonal interactions from the 53-tone JI system. Having the notes arranged in a chromatic formation would create unworkable spatial clusters of hands and mallets, with performers getting in each other’s way and blocking the access to notes that are required to be sounded. The solution to this problem varies. When writing for the diapason you must consider the choreography of performers.

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Dynamics of the glasses are limited but there is a small range that can be used to great effect. When maintaining a constant tone using the stick-slip technique it is possible to increase the volume by circling the finger at a faster rate. This is useful when accenting specific beating pattern rates from groupings of notes. Dynamics are not marked on the scores as I believe it important to leave the choice to the performer. This is reasoned through the tactile nature of the instrument; the sonic intensities can be absorbed not just through listening but also through touch while performing and accordingly adjusted naturally or with group discussion to obtain a sympathetic resonance with the performance environment.

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When the diapason is percussed, the dynamic range is small due to not being able to strike the glass very hard in fear of breakage, but various timbres can be obtained by using different materials to strike the glasses. Wooden sticks can be used if struck softly, creating a ‘tinkling’ sound with rapid decay. Brushes are similar but with a softer attack. The mallets can range from soft felt headed which emit a ‘dull thud’ to semi-soft felt and rubber headed which supply a sharp percussive attack and the clearest tone with extended decay. Extended techniques can also be employed, such as dampening the glass when striking to mute the note and pushing the finger down onto the rim while circling to create a ‘juddering’ effect.

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