On Monday 12th August, the Section held its AGM via Zoom (full details at https://aesmelbourne.org.au/2024-agm/) after which Audio Visual Consultant Alec Graham presented on the topic of:
AVIXA Audio Standards.
After a brief introduction by Section Chairman Graeme Huon of Alec and the trade association AVIXA Huon, Alec started with a brief rundown of his career, up to his current situation where he is an AV Consultant with Aurecon.
He then outlined his involvement with AVIXA right from his early days in the AV industry, involving certification exam preparation work, standards group work and serving as a conference speaker.
He then outlined the three audio standards currently in the AVIXA suite of standards – Dynamic Range in Audiovisual Systems (currently in development), Audio Coverage Uniformity (ACU), and Audio Spectral Balance Standards.
Alec described how the standards provide metrics to enable AV professionals to deliver measurable system performance to clients.
He quoted Chris Foreman – (contributor – Handbook for Sound Engineers -and- Audio Engineering for Sound Reinforcement) as posing two basic questions for designing a sound system “is it loud enough (can everyone hear & understand)” and “will it feedback”.
He commented that the Audio Coverage Uniformity (ACU) Standard’s goal is to objectively evaluate the question “can everyone hear?”
Alec then briefly described the Spectral Balance Standard, its purpose being to define the measurement and verification process for the spectral balance of a system across a frequency range defined by the system’s purpose.
He then went on to give an overview of the Dynamic Range standard, which is currently in development, describing how it will characterise the required SPL, recommended signal-to-noise ratio, and minimum idle noise level (particularly for low NC rooms). He indicated that the standard will also define a measurement procedure.
Alec then described in great detail the Audio Coverage Uniformity standard. This is the standard where he served on the Standards Task Group. He described the Standards process, and how this standard was developed.
He went on to describe a scenario for using the ACU Standard and its defined process to achieve a result for an installation.
He covered in detail the mapping of the space to identify measurement points, and the process of taking and recording those measurements to arrive at a variation figure. He also mentioned that they are time-windowed measurements using a figure of 50ms to ensure only the direct sound and early reflections are measured.
Following his presentation, Alec demonstrated typical scenarios using the ACU Field Guide to design to a specific Standard, giving a sense of the process involved in evaluating performance against the Standard.
He then fielded questions from the group covering a range of topics including dealing with spill from fill loudspeakers, sound field prediction with regard to spectral balance, modelling, and question design as part of the certification process.
The Melbourne Section thanks Alec for the time he put into the preparation and presentation of this important and interesting topic.
We also thank Member Rod Brown for lining up Alec as a speaker.
A PDF of Alec’s slides is available at:
https://aesmelbourne.org.au/wp-content/media/AlecGrahamAVIXAAug2024.pdf
Related Links:
https://www.avixa.org/standards/sound-system-spectral-balance
https://www.avixa.org/standards/audio-coverage-uniformity-in-listener-area
https://www.avixa.org/standards/dynamic-range-in-audiovisual-systems
Author: Peter Smerdon
