R&D Stories: Measuring the Performance of Diaphragm Absorbers

November 28 2018, 05:10
Article by Bruno Fazenda, Kelvin Griffiths, Jorge Castro, and Nathaniel Bailey

In August 2018, as part of its Focus on Acoustics edition, audioXpress published an article documenting the cutting-edge research by leading acoustic experts, Jorge Castro, Nathaniel Bailey (Artnovion) Bruno Fazenda, Kelvin Griffiths (Sense Research, Electroacoustic Design) to determine improvements on precise low-frequency absorption. The tests, performed at Electroacoustic Design, in Porthcawl, South Wales, UK, determined a method to predict finite element analysis of the performance of weighted diaphragmatic membrane absorbers, the predominant acoustic core now employed in Artnovion's latest Eiger Sub Trap range of acoustic panels.

The article we are now making available online aims to describe the technology developed to address the market demand for precise low-frequency absorption. Mid-high frequency absorption is easily achieved through broadband porous absorbers and is readily available on the market—solutions for frequencies from 60 Hz to 120 Hz are considerably rarer and require distinct absorption techniques. Treating even lower frequencies usually involves either vast custom-built solutions or structural alterations to the space. The goal was to create a high-performance absorber with a tunable resonant frequency that could effectively work down to 40 Hz. The tunable element is essential, so a mass-produced product could be adapted to target each rooms’ characteristic resonant frequencies. To tackle these criteria, a novel approach to low-frequency absorber design was required and involved using diaphragm (or membrane) absorbers, a common tool utilized to attenuate standing waves as part of an acoustic treatment. They achieve a high absorption coefficient utilizing a relatively small volume. When paired with a porous acoustic core they present a wider, more linear absorption coefficient, making them a preferred option.

Read the complete article now available here.
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