WHAT IS THE ONE-HANDED VIOLIN?

The One-Handed Violin is a concept for a violin that can be used to perform classical violin repertoire with the use of only one hand. This one-handed violin concept was designed by me in collaboration with The OHMI Trust and Augmented Instruments Laboratory between April and September 2018. The project was supervised by Dr Andrew McPherson (Augmented Instruments Laboratory) and Rachel Wolffsohn (OHMI Trust), and the software was developed in collaboration with Dr Laurel Pardue (Augmented Instruments Laboratory). In this blog post I explain how this project began and where we plan to take it in the future. 

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WHY DESIGN A ONE-HANDED VIOLIN?

The UK government requires primary school curriculum to meet a quota of music lessons. To do so many schools participate in a programme called the WCET (Whole Class Ensemble Teaching), which involves teaching an entire class (usually year 5 students) the same instrument during weekly lessons. Schools often choose which instrument to teach without considering whether students have a disability that affects an upper limb. As a result many children across the UK are excluded from equal participation in these compulsory classes. The most common instrument taught on the WCET programme is the violin.

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The OHMI Trust (One-Handed Musical Instrument Trust) are a Birmingham based charity pioneering the development of accessible musical instruments. Through a yearly instrument design competition, OHMI Trust encourages the development of one-handed versions of traditional two-handed instruments with the goal that the one-handed version fully matches the performance of the traditional version. It is a complex engineering problem to convert an orchestral instrument into a one-handed version and the violin is yet to be adequately converted.

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PREVIOUS ONE-HANDED VIOLIN DESIGNS

Previous attempts at one-handed violin designs include mounting the bow to a pole and brushing the fiddle against it (or a similar adaptive performance technique of holding the bow between crossed legs), Luther Caldwell’s one-armed fiddle featuring a foot controlled mechanical bow, and Tom Fox's circular robotic bow secured to the violin bridge. While some of these designs function for specific users or repertoire, they do not meet the OHMI Trust's requirements of the one-handed version to fully perform classical repertoire. 

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DECISION TO RETAIN THE BOWING HAND 

All the aforementioned designs replace the bowing hand with another technology to perform the bow. However it is very difficult to create a new technology that can perform all the functions of hand controlling a bow. There are seven functions of bow performance including pressure, tilt, skew and bow-bridge distance that must be mastered for correct bow technique. Therefore for this one-handed violin concept it was decided early on that the hand that would be retained would be the hand that controls the bow, and the performance of the hand that controls the strings would be replaced with a controller for the selection of notes and positions, as well as advanced performance techniques such as vibrato and glissandi, and a stand for supporting the weight of the violin.

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DESIGN REQUIREMENTS

When designing a controller to replace the string performance, it was important to consider designing an accessible controller that could be operated by someone with an upper limb disability. This ruled out interfaces controlled by the feet because some disabilities affecting an upper limb also affect a lower limb, and interfaces controlled by the eyes or head because they are not fast enough to perform violin repertoire. 

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DESIGN CONCEPT

After considering the design constraints and problems associated with the creation of a one-handed violin, the concept was created. The concept relies on the performer bowing on the open strings of an electric violin, and using their voice as the controller to pitch-shift the audio of the bowed strings, essentially singing to control the note selection and string performance styles (eg vibrato, glissando etc). 

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Parts:

quadraphonic violin

• regular violin bow

• throat microphone

• BELA micro-computer

• bespoke violin stand (optionally chest-mounted)

• bespoke speaker box

• optional headphones

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How it works:

The performer bows the open strings of a quadrophonic electric violin and uses their voice as a pitch selection controller. The audio created by bowing the string is captured on the string pickup, and is input to the BELA micro-computer. The audio is then pitch-shifted in real-time to the desired pitch as selected via the voice control and output to a speaker. To select the desired pitch, the performer wears a throat microphone and hums the note they wish to perform. 

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DOES IT WORK? 

A series of experiments were run to reveal the efficacy of this concept. We found that the use of voice control as a method of pitch selection is functional when bowing on only one open string at a time, and when selecting a tone within the range of the first octave of a scale, starting on the tone of the open string, and ending just short of the octave tone.  Within this tone range we found that vibrato and glissando are performable without any perceivable latency.

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The performer's voice can be pitch corrected or even transposed into the range of each string once the voice enters the system. However the note selection is limited to the speed of the vocal ability of the performer. Other limitations include that on this current design only one string can be performed at any given time, only the first position can be performed. However these limitations could be addressed in future iterations.

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The throat microphone sometimes moves to an area of the throat that picks up less of the voice and more noise, resulting in a noisier signal. For a while I thought there was a big issue in the pitch-shifting of the strings causing glitches but really it was the microphone placement.

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The biggest limitation on the design is the sound-bleed from bowing on the open strings. To create the desired amplified sound of the electric violin as controlled by the voice controller, the current concept requires the creation of two additional acoustic sounds: the sound of the performer humming and the acoustic sound of the bowed string. The sound of the performer humming is relatively quiet compared to the amplified violin, and is not very distracting to the performer and audience. However on a regular quadraphonic electric violin and playing through the small speaker embedded in the speaker box the acoustic sound of the bowed string is almost as loud as the amplified signal. Therefore while this design is suitable for use through a PA that could mask the sound of the open bowed string, or for use in recording that could use only the direct signal, the current instrument design is not suitable for use acoustically. 

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RECEPTION

I informally showed the One-Handed Violin concept at the OHMI Trust Conference in Birmingham in September 2018. I was overwhelmed by the enthusiasm of the conference attendees . This hugely positive response, as well as the topics discussed over the weekend, made me realise that there is a real need more developments towards the goal of inclusion in music. 

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