Meeting Topic: Acoustics Made Easy
Moderator Name: Graeme Huon
Speaker Name: Matt Harders - Amber Technology
Other business or activities at the meeting:
The Section's Annual General Meeting was held prior to the technical session with reports from the Chairman on Section activities, and the Treasurer on the Section's financial position.
Elections were held for the Section Committee, with the following results:
Graeme Huon — Chairman
Paolo Menolotto — Vice-Chairman
Graham Haynes — Treasurer
Peter Smerdon — Secretary
Rod Staples — Committee Member
Greg Segal — Committee Member
David Hudson — Committee Member
Fabio Marraccini — Committee Member
Lilith Lane — Committee Member
Meeting Location: Virtual meeting via Zoom
In these days of lockdowns, it was yet another meeting via Zoom.
Chairman Graeme Huon introduced Matt Harders, Amber Technologies Brand Manager for Radial/Primacoustic (amongst other brands) to present to us on the topic of Acoustics Made Easy.
Following a brief history of Radial Engineering and how they came to develop the Primacoustic products, Matt fired up the slide show covering his topic.
He started with the issues that drive the need for acoustic treatment — noise pollution, safety, communications, voice intelligibility for messaging in public spaces, comfort, enjoyment, and finally professional entertainment workspaces like recording studios, film stages and broadcast studios.
Matt then identified the situations when engaging an acoustic engineer might be necessary — scenarios like soundproofing, mission critical environments (recording studio, emergency services control rooms etc.), as well as the times when the scope and budget of the project demands a next-level professional approach for a highly predictable result.
He described what can be done to improve acoustic performance by the control of the sound via absorption — citing as the example of absorption affecting the sound the harsh reverberant sound of an empty living room, compared to the same room after the furniture and soft furnishings have been installed.
He introduced and described primary reflections, standing waves, and flutter echo.
With graphics he showed how absorbing primary reflections can reduce the energy, and the effect of these undesirable characteristics.
Responding to an audience question he indicated that the percentage coverage recommendations was between 25-30% of wall area, depending on the use-case for the space. He commented that it does not all need to be on the walls - for example, some could be on the ceiling.
Matt then discussed panel thickness vs efficiency of the panel across the frequency range, showing graphs of the absorption coefficients. These demonstrated that the thicker panels maintain absorption to much lower frequencies.
Matt also compared fibreglass panels to foam absorbers — suggesting that the fibreglass ones were superior at mid and low frequencies due to their higher density, as well as offering practical considerations like being easier to mount, remove, and reuse with their reusable fastener system compared to the glue-on approach typically used with foam.
He then went on to describe some panel designs, and packaged kits suitable for different types and sizes of rooms, and their use-cases.
At the conclusion of the slide presentation Matt opened the floor to questions, where questions covered ceiling panel grid sizes (Imperial and Metric sizes available for many panels) and determining the optimum placement of panels (by establishing the location of sound sources).
Matt then demonstrated the use of the Primacoustic Room Calculator spreadsheet for optimizing the panel configuration for a particular room size and application as well as the use of the online Room Designer CAD package for designing the layout of the panels in the room.
The session concluded with further questions covering performance validation by on site measurement, staggering of panel positioning, and ad-hoc addition of panels to improve an already traditionally treated room.
We thank Matt for his excellent presentation.
A more detailed Report, with links to the resources mentioned, as well as a video recording of the presentation and a PDF version of Matt's slides is available on the AES Melbourne Section website at:
Written By: Peter Smerdon