Harmonix Instruments Pty. Ltd., an Australian advanced acoustic design company run by A/Prof. Dr. Neil McLachlan, was recently commissioned to complete an exciting public space installation at Point Park, Lorimer St, Docklands. The interactive installation features playable bells and gongs with an aesthetic inspired by Australian native flora.
The anodised aluminium bells, which take on shapes inspired by both the grass tree (xanthorrhoea) and grevillea, were simulated using normal modes of vibration analysis with the ADVEA software, ReSHAPE, and then mathematical methods of optimisation were used to tune the bells to harmonic overtones so they produce a clear pitch; an ongoing shared interest of ADVEA and Harmonix. The bells are excited by flicking the stamen, which are manufactured from highly flexible polyester!
The stainless steel gongs, surrounded by stainless mesh and burnished stainless frames, have been tuned by an advanced manufacturing process invented by Harmonix, with a 2-dof CNC machine designed and built by Initial Concept Engineering Industries in cooperation with ADVEA. The motor selection, metal-forming calculations and micro-controller programming were completed by ADVEA. The tuning process involves placing strategic residual stresses in the thin-walled metallic gongs with a stamping procedure, with the aim of adjusting specific modes of vibration, such that a desired frequency array can be achieved in mass-producible objects with a high degree of frequency response variance.
It’s a fantastic public space, thanks to Harmonix creative design process, and we think it will be very well received by visitors to the park.