Chair David Josephson convened the meeting, patent policy read, introduction of attendees, agenda approved, report of previous meeting held 2018-10 in New York approved.
In attendence were D Josephson, H Singleton, H Wittek, P Mapp, B Olson, J Boley, J Berryman, J Page, R Cabot, J Brito *, M Rafaelof * (* denotes by electronic link).
Subsequent to the meeting, Dr. Roland Sottek from HEAD Acoustics accepted the chair’s earlier invitation to join the working group, and we will welcome his participation. Andrew Christian and Durand Begault from NASA sent their regrets for this meeting.
David Josephson presented a summary of the reasons for using loudness metrics including examples of noises clearly audible in background despite being 14 dB lower in sound pressure level. The slides are available on the WG doc site.
Menachem Rafaelof reminded that prominent discrete tones contribute significantly to loudness and annoyance. They are addressed in ECMA 74, a copy of which is available on the WG doc site along with some relevant papers. They are also addressed in the PNL(T) metric underlying aircraft certification, BS4142, ISO 7779 and other methods.
Similar “penalty” metrics are applied for impulsivity or intermittency, such as Nordtest ACOU 112. It is hoped that a more general metric can be defined that will eliminate the need for such corrections.
Peter Mapp reported that progress was being made in the Sound Reinforcement TC on metrics to capture noise emission from outdoor events. A report from their noise pollution working group is expected soon.
Herb Singleton agreed to summarize some of the applicable standards and reference materials on loudness and sound quality metrics.
Members are encouraged to upload relevant research documents to the SC-04-09 document page. Credentials for access are granted by the AESSC Standards Manager – those wishing to join the group should notify firstname.lastname@example.org. If other standards are required for analysis and incorporation please identify them and we will try to add them to the repository. Access is a little simpler if you are already an AES member, but possible even if you are not. There is no charge for participation but companies benefiting from the work of this working group are encouraged to become AESSC Standards Sustainers, see http://www.aes.org/standards/support/
In the future there may be a liaison with the Vertical Flight Society’s eVTOL Technical Committee Noise Assessment Working Group.
There was no new business.
The next meeting will be held in Vienna, Austria 2020-05, in conjunction with the AES 148th convention.