Report of the meeting of the SC-04-08 Working Group on Measurement and Equalization of sound systems in rooms, of the SC-04 Subcommittee on Acoustics, held in New York, 2015-10-31
The meeting was convened by interim chair E.B. Brixen.
The agenda and report of the previous meeting, held in Warsaw, Poland, 2015-05-09, were accepted as written.
Development projects
AES-X218 - "Measurement and calibration of sound systems in rooms."
The chair pointed out that the project now needs to enter the writing
process, as there already have been discussions, however, nothing has been
concluded yet.
SMPTE document: At the last meeting, it was mentioned that the SMPTE would have finished a
document on measurement techniques for cinema system calibration by this
time. However, we understand that this document has not been finished yet. A
draft version is expected to be put to a vote by next month (November 2015).
It was mentioned that it should be regarded as an interim project, until a
methodology involving more modern measurement techniques is described. In
this respect, the SMPTE is also waiting for the AES-X218 to finish.
Definition of "sound systems": The chair wanted a clarification whether the term "sound systems" includes
the frontend with live microphones. A reproduction system solely cover
B-chain. However, reinforcement systems include microphones. As the
loudspeakers are common for both systems it was agreed that it is most
appropriate to work on a document that encompasses the reproduction side of
the system, and then eventually add microphones in an addendum.
Parameters to measure: In order to move on with the project it was decided define the parameters to
measure. When decided, the group can move on to the measurement procedures.
The following parameters were proposed:
• Frequency response
• Sound pressure level (SPL)
• Coverage
• Speech Intelligibility
• Distortion
• Background Noise (acoustical)
• System noise (acoustical)
• Reverberation time
• Gain structure
• Max SPL
• Temporal response / Impulse response
Frequency response and SPL are regarded as top-level parameters that have a
fundamental influence on other parameters.
Next step: With this meeting report, all members are urged to comment on whether the list
of parameters is adequate/complete as soon as possible. Commenting on the
reflector should be finished by the end of November.
Then members (of the working group) must assign themselves to writing groups
each covering measuring procedures for one (or perhaps more) parameter to be
documented.
Phone meetings can be held at an regular basis to make things happen before
the next convention in June.
AES-X219 "Method of measurement for frequency and impulse response of sound
systems in auditoria"
This project is awaiting a detailed scope. The project is postponed until the
AES-X218 has reached some conclusions which may or may not involve impulse
response.
Liaisons
There were no new liaison issues.
New Projects
No new projects were proposed.
New Business
No new business was proposed.
The next face-to-face meeting will be schedued in conunction with the AES 140th Convention in Paris, France, 2016-06.
Virtual meetings are also planned to help progress the AES-X218 project. The first virtual meeting will be scheduled around 2015-12-01.
